Publications

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Publications

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Ramamurthy, B., Rouskas, G. & Sivalingam(eds.), K. (2011), "Next-Generation Internet Architectures and Protocols", February, 2011. Cambridge University Press.
BibTeX:
@book{RaRS10,
  author = {Byrav Ramamurthy and George Rouskas and Krishna Sivalingam(eds.)},
  title = {Next-Generation Internet Architectures and Protocols},
  publisher = {Cambridge University Press},
  year = {2011},
  note = {(under preparation)},
  url = {http://www.cambridge.org/us/catalogue/catalogue.asp?isbn=9780521113687},
  doi = {ISBN 9780521113687}
}
Y. Wang, Ramamurthy, B. & Y. Xue (2010), "A Key Management Protocol for Wireless Sensor Networks with Multiple Base Stations", In Handbook on Sensor Networks. World Scientific Publishing Co..
BibTeX:
@incollection{WaRX09--BookChapter,
  author = {Y. Wang and Byrav Ramamurthy and Y. Xue},
  title = {A Key Management Protocol for Wireless Sensor Networks with Multiple Base Stations},
  booktitle = {Handbook on Sensor Networks},
  publisher = {World Scientific Publishing Co.},
  year = {2010},
  note = {(to appear)},
  doi = {ISBN 978-981-283-730-1}
}
C. Cavdar, S. Rai, Gencata, A., Ramamurthy, B. & Mukherjee, B. (2010), "Logical-Topology Design and Optimization", In The Handbook of Graph Algorithms and Applications, Volume II: Applications. New York, NY Chapman & Hall/CRC Computer & Information Science Series.
BibTeX:
@incollection{InThSo07-Logical--NSTD,
  author = {C. Cavdar and S. Rai and Aysegul Gencata and Byrav Ramamurthy and Biswanath Mukherjee},
  title = {Logical-Topology Design and Optimization},
  booktitle = {The Handbook of Graph Algorithms and Applications, Volume II: Applications},
  publisher = {Chapman & Hall/CRC Computer & Information Science Series},
  year = {2010},
  note = {ISBN: 9781584885979},
  url = {http://www.crcpress.com/product/isbn/9781584885979}
}
P. Angu & Ramamurthy, B. (2010), "Continuous and Parallel Optimization of Dynamic Bandwidth Scheduling for WDM Networks", In GLOBECOM '10. IEEE Global Telecommunications Conference. December 2010.
Abstract: Many scientific and Grid applications require high-speed circuits of guaranteed bandwidth for scheduled transfers. Offline optimization of dynamic scheduled bandwidth demands is an efficient way of finding the near-optimal solution to the bandwidth scheduling problem. In this paper, we propose a continuous and parallel optimization method to address the dynamic and deterministic bandwidth scheduling problem in next generation wavelength-division multiplexing (WDM) networks. In this method a greedy algorithm and genetic algorithm are run in parallel in separate threads and both of them take the Dynamic Scheduled Bandwidth Demand (D-SBD) as their input. The user gets his response only from the greedy algorithm and hence he will get a deterministic answer in a short amount of time. The genetic algorithm takes as one of its inputs the output of the greedy algorithm and does the optimization of the D-SBDs with minimizing blocking probability as its fitness function. The greedy algorithm copies the optimized reservation database of the genetic algorithm at regular intervals. The user submitting a D-SBD request is unaware of the optimization done by the genetic algorithm. This method is evaluated using both trace driven simulation of real network traffic from the DOE ESnet network and stochastic traffic in ESnet network topology and a 24 node network topology. We also compare our approach with an earlier proposed method called re-optimization at blocking. Adding the genetic algorithm improves the performance of the network (in terms of blocking probability) compared to using only the greedy approach or the re-optimization at blocking method.
BibTeX:
@inproceedings{AnRa10-gcom,
  author = {P. Angu and Byrav Ramamurthy},
  title = {Continuous and Parallel Optimization of Dynamic Bandwidth Scheduling for WDM Networks},
  booktitle = {GLOBECOM '10. IEEE Global Telecommunications Conference},
  year = {2010},
  note = {(to appear)}
}
A. Ravula & Ramamurthy, B. (2010), "A Tabu Search Approach for Joint Scheduling of Resources in a Lambda Grid Network", In GLOBECOM '10. IEEE Global Telecommunications Conference. Miami, FL, USA. December 2010.
Abstract: Advanced distributed applications in engineering, scientific and

business domains that are highly data-intensive demand

high-performance computing platforms. Grid networks based on optical

technology provide a promising approach to create efficient

infrastructure to support such applications. These networks, termed in

general as Lambda Grid networks, are based on optical circuit

switching and employ wavelength division multiplexing and optical

lightpaths. In this paper, we propose an approach based on Tabu Search

heuristic for joint scheduling of computing, network and storage

resources in a Lambda Grid network. The objectives are to minimize

cost by efficient usage of resources and to minimize total completion

time of job execution. The results are compared to a Greedy

approach. Simulation results from both the methods show that the Tabu

search heuristic performed better than the greedy approach in

optimizing both the cost and completion time objectives.

BibTeX:
@inproceedings{RaRa10-gcom,
  author = {A. Ravula and Byrav Ramamurthy},
  title = {A Tabu Search Approach for Joint Scheduling of Resources in a Lambda Grid Network},
  booktitle = {GLOBECOM '10. IEEE Global Telecommunications Conference},
  year = {2010},
  note = {(to appear)}
}
Z. Ouyang, Xu, L. & Ramamurthy, B. (2010), "Diverse Community: Demand differentiation in P2P Live Streaming", December, 2010.
BibTeX:
@article{OuXR09--NSTD,
  author = {Z. Ouyang and Lisong Xu and Byrav Ramamurthy},
  title = {Diverse Community: Demand differentiation in P2P Live Streaming},
  year = {2010},
  note = {(to appear)}
}
Y. Xue, Ramamurthy, B. & Burbach, M. (2010), "A Two-Tier Wireless Sensor Network Infrastructure for Large-Scale Real-Time Groundwater Monitoring", In Proceedings, 5th IEEE International Workshop on Practical Issues in Building Sensor Network Applications (SenseApp 2010). October 2010.
Abstract: In this paper, we describe the design, implementation and deployment details of a two-tier real-time environmental monitoring network in Nebraska. Our state-wide sensor network infrastructure uses typical Wireless Sensor Network (WSN) structure at tier-two to conduct dynamic sensing tasks with high resolution and flexibility. The satellite communication technology is used at tier-one to provide reliable and low-cost long-haul connectivity between each local WSN and the central base station. By the end of 2009, the entire tier-one infrastructure has been designed and deployed to provide state-wide wireless connectivity for 54 monitoring sites equipped with 1-4 water level transducers. A data and network management framework has also been developed to enable the remote network re-tasking and network performance analysis from a central base station. The network web portal offers integrated real-time and historical groundwater data to worldwide users. The deployed infrastructure will serve as the prototype network to expedite the commercial adoption of large-scale WSN design for long-term environmental monitoring applications.
BibTeX:
@inproceedings{XuRB10-senseapp,
  author = {Y. Xue and Byrav Ramamurthy and Mark Burbach},
  title = {A Two-Tier Wireless Sensor Network Infrastructure for Large-Scale Real-Time Groundwater Monitoring},
  booktitle = {Proceedings, 5th IEEE International Workshop on Practical Issues in Building Sensor Network Applications (SenseApp 2010)},
  year = {2010},
  note = {(to appear)}
}
M. Subedee, P. Angu, Ramamurthy, B. & Christensen, K. (2010), "GpENI@UNL: UNL Contributions to a Regional Network Testbed". July, 2010.
BibTeX:
@misc{SARC-gpn2010,
  author = {M. Subedee and P. Angu and Byrav Ramamurthy and Kent Christensen},
  title = {GpENI@UNL: UNL Contributions to a Regional Network Testbed},
  year = {2010},
  note = {(poster)}
}
Y. Xue, Vuran, M.C. & Ramamurthy, B. (2010), "Cost-Efficiency of Anycast-Based Forwarding in Duty-Cycled WSNs with Lossy Channel", In IEEE Conference on Sensor, Mesh and Ad Hoc Communications and Networks (SECON). June 2010., pp. 1-9.
BibTeX:
@inproceedings{XuVR10-SECON,
  author = {Y. Xue and M. Can Vuran and Byrav Ramamurthy},
  title = {Cost-Efficiency of Anycast-Based Forwarding in Duty-Cycled WSNs with Lossy Channel},
  booktitle = {IEEE Conference on Sensor, Mesh and Ad Hoc Communications and Networks (SECON)},
  year = {2010},
  pages = {1--9},
  url = {http://dx.doi.org/10.1109/SECON.2010.5508263},
  doi = {http://dx.doi.org/10.1109/SECON.2010.5508263}
}
M. Wang, Xu, L. & Ramamurthy, B. (2010), "Comparing Multi-Channel Peer-to-Peer Video Streaming System Designs", In LANMAN 2010. The 17th IEEE Workshop on Local and Metropolitan Area Networks. May 2010., pp. 1-6.
BibTeX:
@inproceedings{WaXR10-LANMAN,
  author = {M. Wang and Lisong Xu and Byrav Ramamurthy},
  title = {Comparing Multi-Channel Peer-to-Peer Video Streaming System Designs},
  booktitle = {LANMAN 2010. The 17th IEEE Workshop on Local and Metropolitan Area Networks},
  year = {2010},
  pages = {1--6},
  url = {http://dx.doi.org/10.1109/LANMAN.2010.5507144},
  doi = {http://dx.doi.org/10.1109/LANMAN.2010.5507144}
}
Sterbenz, J.P., Medhi, D., Ramamurthy, B., Scoglio, C., Hutchison, D., Plattner, B., Anjali, T., Scott, A., Buffington, C., Monaco, G.E., Gruenbacher, D., McMullen, R., Rohrer, J.P., Sherrell, J., Angu, P., Cherukuri, R., Qian, H. & Tare, N. (2010), "The Great Plains Environment for Network Innovation (GpENI): A Programmable Testbed for Future Internet Architecture Research", In Proceedings of the 6th International Conference on Testbeds and Research Infrastructures for the Development of Networks & Communities (TridentCom). Berlin, Germany. May 2010., pp. 1-14.
Abstract: The Great Plains Environment for Network Innovation Ð

GpENI is an international programmable network testbed centered on

a regional optical network in the Midwest US, providing ßexible

infrastructure across the entire protocol stack. The goal of GpENI is to build a

collaborative research infrastructure enabling the community to conduct

experiments in future Internet architecture. GpENI is funded in part by

the US National Science Foundation GENI (Global Environments for

Network Innovation) program and by the EU FIRE (Future Internet

Research and Experimentation) Programme, and is affiliated with a project

funded by the NSF FIND (Future Internet Design) Program.

BibTeX:
@inproceedings{Ster10-tri,
  author = {James P.G. Sterbenz and Deep Medhi and Byrav Ramamurthy and Caterina Scoglio and David Hutchison and Bernhard Plattner and Tricha Anjali and Andrew Scott and Cort Buffington and Gregory E. Monaco and Don Gruenbacher and Rick McMullen and Justin P. Rohrer and John Sherrell and Pragatheeswaran Angu and Ramkumar Cherukuri and Haiyang Qian and Nidhi Tare},
  title = {The Great Plains Environment for Network Innovation (GpENI): A Programmable Testbed for Future Internet Architecture Research},
  booktitle = {Proceedings of the 6th International Conference on Testbeds and Research Infrastructures for the Development of Networks & Communities (TridentCom)},
  year = {2010},
  pages = {1--14},
  url = {http://cse.unl.edu/~pangu/paper/trident2010.pdf}
}
Z. Ouyang, Xu, L. & Ramamurthy, B. (2010), "On Demand Heterogeneity in P2P Live Streaming", In ICC '10. IEEE International Conference on Communications. Cape Town, South Africa. May 2010.
Abstract: Peer-to-peer (P2P) technology has become an attractive approach for enabling large-scale video streaming applications, but the factor of usersÕ subjective preferences is usually ignored in such networks. As users have different demands on video quality, adaptive streaming has been proposed to improve bandwidth efficiency while still maintaining usersÕ satisfaction. However, in providing adaptive streaming rate services, P2P live streaming design faces the following challenge: how to provide all users uninterrupted video with their desired qualities in case their demands change dynamically? To shed more light on providing adaptive streaming rates according to usersÕ demands in P2P live streaming systems, we model the problem as a resource demand and supply problem. We propose an optimization method to improve bandwidth efficiency through efficient bandwidth allocation. We develop a tiered overlay and a price-rated mechanism to implement cooperation among peers, and present a framework to address the challenge via efficient bandwidth allocation and group cooperation. Through complementary simulations, we evaluate the effectiveness of the proposed framework, and show that it effectively helps existing solutions, such as the Partial Participation Scheme (PPS), achieve better performance.
BibTeX:
@inproceedings{OuXR10-icc,
  author = {Z. Ouyang and Lisong Xu and Byrav Ramamurthy},
  title = {On Demand Heterogeneity in P2P Live Streaming},
  booktitle = {ICC '10. IEEE International Conference on Communications},
  year = {2010},
  url = {http://dx.doi.org/10.1109/ICC.2010.5502423},
  doi = {http://dx.doi.org/10.1109/ICC.2010.5502423}
}
M. Wang, Xu, L. & Ramamurthy, B. (2010), "Linear programming models for multi-channel P2P streaming systems", In IEEE INFOCOM 2010 Mini-Conference Program. March 2010., pp. 1-5.
Abstract: Most of the commercial P2P video streaming deployments

support hundreds of channels and are referred to as multichannel

systems. Measurement studies show that bandwidth

resources of different channels are highly unbalanced and thus recent

research studies have proposed various protocols to improve

the streaming qualities for all channels by enabling cross-channel

cooperation among multiple channels. However, there is no general

framework for comparing existing and potential designs for

multi-channel P2P systems. The goal of this paper is to establish

tractable models for answering the fundamental question in

multi-channel system designs: Under what circumstances, should

a particular design be used to achieve the desired streaming

quality with the lowest implementation complexity? To achieve

this goal, we first classify existing and potential designs into

three categories, namely Naive Bandwidth allocation Approach

(NBA), Passive Channel-aware bandwidth allocation Approach

(PCA) and Active Channel-aware bandwidth allocation Approach

(ACA). Then, we define the bandwidth satisfaction ratio as

a performance metric to develop linear programming models

for the three designs. The proposed models are independent of

implementations and can be efficiently solved due to the linear

property, which provides a way of numerically exploring the

design space of multi-channel systems and developing closed-form

solutions for special systems.

BibTeX:
@inproceedings{WaXR10INF,
  author = {M. Wang and Lisong Xu and Byrav Ramamurthy},
  title = {Linear programming models for multi-channel P2P streaming systems},
  booktitle = {IEEE INFOCOM 2010 Mini-Conference Program},
  year = {2010},
  pages = {1--5},
  note = {(Acceptance Rate: 24%)},
  url = {http://dx.doi.org/10.1109/INFCOM.2010.5462230},
  doi = {http://dx.doi.org/10.1109/INFCOM.2010.5462230}
}
Y. Wang, Ramamurthy, B., X. Zou & Y. Xue (2009), "An Efficient Scheme for Removing Compromised Sensor Nodes from Wireless Sensor Networks", Wiley Security and Communication Networks.
Abstract: The goal of key management is to establish the required keys between sensor nodes which exchange data. A key management protocol includes two aspects: key distribution and key revocation. Key distribution has been extensively studied in the context of sensor networks. However, key revocation has received relatively little attention. In this paper, we first review and summarize the current key revocation schemes for sensor networks. Then, we present an efficient scheme, KeyRev, for removing compromised sensor nodes from a wireless sensor network (WSN). Unlike most proposed key revocation schemes focusing on removing the compromised keys on the sensor nodes, the KeyRev scheme uses key update techniques to obsolesce the keys owned by the compromised sensor nodes and thus remove the nodes from the network. We analyze the security of the KeyRev scheme and compare its performance against another centralized key revocation scheme and a distributed key revocation scheme. Our analyses show that the KeyRev scheme is secure in spite of not removing the pre-distributed key materials at compromised sensor nodes. Simulation results also indicate that the KeyRev scheme is scalable and performs very well compared with other key revocation schemes in WSNs.
BibTeX:
@article{WRZX08-jscn,
  author = {Y. Wang and Byrav Ramamurthy and X. Zou and Y. Xue},
  title = {An Efficient Scheme for Removing Compromised Sensor Nodes from Wireless Sensor Networks},
  journal = {Wiley Security and Communication Networks},
  year = {2009},
  note = {appeared online December 2008},
  url = {http://dx.doi.org/10.1002/sec.89},
  doi = {http://dx.doi.org/10.1002/sec.89}
}
R. Tewari & Ramamurthy, B. (2009), "Optimal Segment Size for Fixed-sized Segment Protection in Wavelength-routed Optical Networks", In IEEE International Symposium on Advanced Networks and Telecommunication Systems (ANTS). December 2009., pp. 1-3.
Abstract: Protecting a network against link failures is a major challenge faced by network operators. The protection scheme has to address two important objectives - fast recovery and minimizing the amount of backup resources needed. Every protection algorithm is a tradeoff between these two objectives. In this paper, we study the problem of segment protection. In particular, we investigate what is the optimal segment size that obtains the best tradeoff between the time taken for recovery and minimizing the bandwidth used by the backup segments. We focus on the uniform fixed-length segment protection method, where each primary path is divided into fixed-length segments, with the exception of the last segment in the path. We observe that the optimal segment size for a given network depends on several factors such as the topology and the ratio of the costs involved.
BibTeX:
@inproceedings{TeRa09,
  author = {R. Tewari and Byrav Ramamurthy},
  title = {Optimal Segment Size for Fixed-sized Segment Protection in Wavelength-routed Optical Networks},
  booktitle = {IEEE International Symposium on Advanced Networks and Telecommunication Systems (ANTS)},
  year = {2009},
  pages = {1--3},
  url = {http://dx.doi.org/10.1109/ANTS.2009.5409857},
  doi = {http://dx.doi.org/10.1109/ANTS.2009.5409857}
}
M. Wang, Xu, L. & Ramamurthy, B. (2009), "A Flexible Divide-And-Conquer Protocol for Multi-View Peer-to-Peer Live Streaming", In IEEE P2P '09: Ninth International Conference on Peer-to-Peer Computing. Seattle, WA. September 2009., pp. 291-300.
Abstract: Multi-view peer-to-peer (P2P) live streaming systems have recently emerged, where a user can simultaneously watch multiple channels. Previous work on multi-view P2P streaming solves the fundamental inter-channel bandwidth competition problem at the individual user level, and thus can be used with very limited types of streaming protocols. In this paper, we propose a new protocol for multi-view P2P streaming, called Divide-and-Conquer (DAC), which efficiently solves the inter-channel bandwidth competition problem using a divide-and-conquer strategy at the channel level, and thus is flexible to work with various streaming protocols. This makes DAC more suitable for upgrading current single-view P2P live streaming systems to multi-view P2P live streaming systems. Our extensive packet-level simulations show that DAC is efficient in allocating the overall system bandwidth among competing channels, is flexible in working with various streaming protocols, and is scalable in supporting a large number of users and channels.
BibTeX:
@inproceedings{WaXR09-p2p09,
  author = {M. Wang and Lisong Xu and Byrav Ramamurthy},
  title = {A Flexible Divide-And-Conquer Protocol for Multi-View Peer-to-Peer Live Streaming},
  booktitle = {IEEE P2P '09: Ninth International Conference on Peer-to-Peer Computing},
  year = {2009},
  pages = {291--300},
  note = {(Acceptance Rate: 19%)},
  url = {http://dx.doi.org/10.1109/P2P.2009.5284541},
  doi = {http://dx.doi.org/10.1109/P2P.2009.5284541}
}
Y. Xue, Ramamurthy, B. & Y. Wang (2009), "LTRES: A Loss-Tolerant Reliable Event Sensing Protocol for Wireless Sensor Networks", Computer Communications., September, 2009. Vol. 32, pp. 1666-1676.
Abstract: Many Wireless Sensor Network (WSN) transport protocols proposed in recent studies focus on providing end-to-end reliability as in TCP. However, traditional end-to-end reliability enforcement is energy and time consuming for common loss-tolerant applications in WSNs. In this paper, a Loss-Tolerant Reliable Event Sensing protocol (LTRES) is proposed based on the particular reliability requirements for dynamic event observation in WSNs. According to the application-specific requirements, a reliable event sensing threshold at the transport layer is determined by the sink. A distributed source rate adaptation mechanism is designed, incorporating a loss rate based lightweight congestion control mechanism, to regulate the data traffic injected into the network so that the reliability requirements can be satisfied. An equation based fair rate control algorithm is designed to improve the fairness among the traffic flows sharing the congestion path. The performance evaluations show that LTRES can provide event-based loss-tolerant reliable data transport service for multiple events with short convergence time, low loss rate and high overall bandwidth utilization.
BibTeX:
@article{XuRW09-comcom,
  author = {Y. Xue and Byrav Ramamurthy and Y. Wang},
  title = {LTRES: A Loss-Tolerant Reliable Event Sensing Protocol for Wireless Sensor Networks},
  journal = {Computer Communications},
  year = {2009},
  volume = {32},
  pages = {1666-1676},
  url = {http://dx.doi.org/10.1016/j.comcom.2009.06.006},
  doi = {http://dx.doi.org/10.1016/j.comcom.2009.06.006}
}
Ramamurthy, B. & Katsaggelos, A. (2009), "Message from the General Chairs", In ICCCN 2009. The 18th International Conference on Computer Communications and Networks. August 2009.
BibTeX:
@inproceedings{ICCCN09,
  author = {Ramamurthy, Byrav and Aggelos Katsaggelos},
  title = {Message from the General Chairs},
  booktitle = {ICCCN 2009. The 18th International Conference on Computer Communications and Networks},
  journal = {Proceedings, ICCCN 2009 Conference. The 18th International Conference on Computer Communications and Networks},
  year = {2009},
  url = {http://dx.doi.org/10.1109/ICCCN.2009.5235412},
  doi = {http://dx.doi.org/10.1109/ICCCN.2009.5235412}
}
M. Wang, Xu, L. & Ramamurthy, B. (2009), "Providing Statistically Guaranteed Streaming Quality for Peer-to-Peer Live Streaming", In The 19th ACM International Workshop on Network and Operating Systems Support for Digital Audio and Video (NOSSDAV). Williamsburg, VA. June 2009., pp. 127-132.
Abstract: Most of the literature on peer-to-peer (P2P) live streaming focuses on how to provide best-effort streaming quality by efficiently using the system bandwidth; however, there is no guarantee about the provided streaming quality. This paper considers how to provide statistically guaranteed streaming quality to a P2P live streaming system. We study a class of admission control algorithms which statistically guarantee that a P2P live streaming system has sufficient overall bandwidth. Our results show that there is a tradeoff between the user blocking rate and user-behavior insensitivity (i.e., whether the system performance is insensitive to the fine statistics of user behaviors). We also find that the system performance is more sensitive to the distribution change of user inter-arrival times than to that of user lifetimes.
BibTeX:
@inproceedings{WaXR09-nossdav09,
  author = {M. Wang and Lisong Xu and Byrav Ramamurthy},
  title = {Providing Statistically Guaranteed Streaming Quality for Peer-to-Peer Live Streaming},
  booktitle = {The 19th ACM International Workshop on Network and Operating Systems Support for Digital Audio and Video (NOSSDAV)},
  year = {2009},
  pages = {127--132},
  note = {(Acceptance Rate: 25%)},
  url = {http://dx.doi.org/10.1145/1542245.1542274},
  doi = {http://dx.doi.org/10.1145/1542245.1542274}
}
V. Lakshmiraman & Ramamurthy, B. (2009), "Joint Computing and Network Resource Scheduling in a Lambda Grid Network", In ICC '09. IEEE International Conference on Communications. Dresden, Germany. June 2009., pp. 1-5.
Abstract: Data-intensive grid applications require huge data transfers between grid computing nodes. These computing nodes, where computing jobs are executed, are usually geographically separated. A grid network that employs optical wavelength division multiplexing (WDM) technology and optical switches to interconnect computing resources with dynamically provisioned multigigabit rate bandwidth lightpath is called a lambda grid network. A computing task may be executed on any one of several computing nodes which possesses the necessary resources. In order to reflect the reality in job scheduling, allocation of network resources for data transfer should be taken into consideration. However, few scheduling methods consider the communication contention on lambda grids. In this paper, we investigate the joint scheduling problem while considering both optical network and computing resources in a lambda grid network. The objective of our work is to maximize the total number of jobs that can be scheduled in a lambda grid network. An adaptive routing algorithm is proposed and implemented for accomplishing the communication tasks for every job submitted in the network. Four heuristics (FIFO, ESTF, LJF, RS) are implemented for job scheduling of the computational tasks. Simulation results prove the feasibility and efficiency of the proposed solution.
BibTeX:
@inproceedings{LaRa09-icc09,
  author = {V. Lakshmiraman and Byrav Ramamurthy},
  title = {Joint Computing and Network Resource Scheduling in a Lambda Grid Network},
  booktitle = {ICC '09. IEEE International Conference on Communications},
  year = {2009},
  pages = {1--5},
  url = {http://dx.doi.org/10.1109/ICC.2009.5199110},
  doi = {http://dx.doi.org/10.1109/ICC.2009.5199110}
}
Z. Ouyang, Xu, L. & Ramamurthy, B. (2009), "A Cooperative Scheme for Dynamic Window Resizing in P2P Live Streaming", In ICC '09. IEEE International Conference on Communications. Dresden, Germany. June 2009., pp. 1-5.
Abstract: Due to their widespread popularity, peer-to-peer (P2P) live streaming systems have become a great challenge for Internet service providers (ISPs) as they consume huge amount of Internet bandwidth. By observing that different users may watch a channel with different window sizes, we propose a cooperative scheme called partial participation scheme (PPS) in which different peers request a video stream at different rates based on their window sizes, and a subset of peers viewing the video stream using a small window work as helpers to forward extra data to help other peers using a large window. By reducing streaming rate received by small-window peers, the total amount of consumed bandwidth decreases without sacrificing users' satisfaction. PPS includes peer cooperative bandwidth allocation algorithms and neighbor maintenance mechanisms to achieve short resizing delay when a peer changes its window between different sizes. We evaluate the performance of PPS via a comprehensive set of metrics generated from extensive simulations. Our simulation results show that PPS greatly reduces the bandwidth consumption, achieves short resizing delay, and maintains high and stable streaming quality.
BibTeX:
@inproceedings{OuXR09-icc09,
  author = {Z. Ouyang and Lisong Xu and Byrav Ramamurthy},
  title = {A Cooperative Scheme for Dynamic Window Resizing in P2P Live Streaming},
  booktitle = {ICC '09. IEEE International Conference on Communications},
  year = {2009},
  pages = {1-5},
  url = {http://dx.doi.org/10.1109/ICC.2009.5198585},
  doi = {http://dx.doi.org/10.1109/ICC.2009.5198585}
}
Z. Ouyang, Xu, L. & Ramamurthy, B. (2009), "A Cooperative Scheme for Dynamic Window Resizing in P2P Live Streaming", In ICC '09: IEEE International Conference on Communications. Beijing, P.R. China. June 2009., pp. 1-5.
Abstract: Due to their widespread popularity, peer-to-peer (P2P) live streaming systems have become a great challenge for Internet service providers (ISPs) as they consume huge amount of Internet bandwidth. By observing that different users may watch a channel with different window sizes, we propose a cooperative scheme called partial participation scheme (PPS) in which different peers request a video stream at different rates based on their window sizes, and a subset of peers viewing the video stream using a small window work as helpers to forward extra data to help other peers using a large window. By reducing streaming rate received by small-window peers, the total amount of consumed bandwidth decreases without sacrificing users' satisfaction. PPS includes peer cooperative bandwidth allocation algorithms and neighbor maintenance mechanisms to achieve short resizing delay when a peer changes its window between different sizes. We evaluate the performance of PPS via a comprehensive set of metrics generated from extensive simulations. Our simulation results show that PPS greatly reduces the bandwidth consumption, achieves short resizing delay, and maintains high and stable streaming quality.
BibTeX:
@inproceedings{OuXR09-ICC,
  author = {Z. Ouyang and Lisong Xu and Byrav Ramamurthy},
  title = {A Cooperative Scheme for Dynamic Window Resizing in P2P Live Streaming},
  booktitle = {ICC '09: IEEE International Conference on Communications},
  year = {2009},
  pages = {1--5},
  url = {http://dx.doi.org/10.1109/ICC.2009.5198585},
  doi = {http://dx.doi.org/10.1109/ICC.2009.5198585}
}
J. Feng, K. Kothamachu, Xu, L. & Ramamurthy, B. (2009), "Overlay construction in mobile peer-to-peer networks", In Mobile Peer-to-Peer Computing for Next Generation Distributed Environments: Advancing Conceptual and Algorithmic Applications., Hardcover., May, 2009. IGI Global.
BibTeX:
@incollection{FKXR09--BookChapter,
  author = {J. Feng and K. Kothamachu and L. Xu and B. Ramamurthy},
  title = {Overlay construction in mobile peer-to-peer networks},
  booktitle = {Mobile Peer-to-Peer Computing for Next Generation Distributed Environments: Advancing Conceptual and Algorithmic Applications},
  publisher = {IGI Global},
  year = {2009},
  note = {ISBN: 9781605667157},
  url = {http://www.igi-global.com/reference/details.asp?id=34281},
  doi = {http://dx.doi.org/10.4018/978-1-60566-715-7}
}
J. Feng, Z. Ouyang, Xu, L. & Ramamurthy, B. (2009), "Packet Reordering in High-Speed Networks and Its Impact on High-Speed TCP Variants", Computer Communications., January, 2009. Vol. 32(1), pp. 62-68.
Abstract: Several recent Internet measurement studies show that the higher the packet sending rate, the higher the packet-reordering probability. This implies that recently proposed high-speed TCP variants are more likely to experience packet reordering than regular TCP in high-speed networks, since they are designed to achieve much higher throughput than regular TCP in these networks. In this paper, we first study the characteristics of packet reordering in high speed networks. Second, we verify the impact of packet reordering on high speed TCP variants and evaluate the effectiveness of the existing reordering-tolerant TCP enhancements using simulations. Our simulation results demonstrate that high-speed TCP variants perform poorly in the presence of packet reordering, and existing reordering-tolerant algorithms can significantly improve the performance of high-speed TCP variants.
BibTeX:
@article{FOXR08-comcom,
  author = {J. Feng and Z. Ouyang and Lisong Xu and Byrav Ramamurthy},
  title = {Packet Reordering in High-Speed Networks and Its Impact on High-Speed TCP Variants},
  journal = {Computer Communications},
  year = {2009},
  volume = {32},
  number = {1},
  pages = {62-68},
  url = {http://dx.doi.org/10.1016/j.comcom.2008.09.022},
  doi = {http://dx.doi.org/10.1016/j.comcom.2008.09.022}
}
W. Yao, Sahin, G., M. Li & Ramamurthy, B. (2009), "Analysis of Multi-Hop Traffic Grooming in WDM Mesh Networks", Optical Switching and Networking., January, 2009. Vol. 6(1), pp. 64-75.
Abstract: Traffic grooming is an essential functionality of WDM optical networks to provision multi-granularity subwavelength connections. Depending on the number of lightpaths allowed in a connection route, traffic grooming can be classified as single-hop traffic grooming (SH-TG) and multi-hop traffic grooming (MH-TG). MH-TG is more general and resource-efficient than SH-TG, because it allows connections from different source-destination pairs to share the bandwidth of a lightpath. In this paper, we propose a MH-TG algorithm, namely the fixed-order multi-hop (FOMH) grooming algorithm, based on the fixed-alternate routing approach. We introduce the grooming node selection (GNS) problem in MH-TG and propose three grooming policies, namely exhaustive sequential (ES), limited-hop sequential (LHS) and load sharing (LS) policies, to address the GNS problem. These policies represent different trade-offs among blocking probability, computational complexity and transceiver requirements. Given that the analysis of MH-TG is a relatively unexplored area, we propose an analytical model to evaluate the blocking performance of MH-TG using FOMH and the LS grooming policy. To address the multi-layered routing and multi-rate connection characteristics of traffic grooming, we introduce a novel multi-level decomposition approach in our analytical model which decomposes traffic at four different levels, namely alternate path, connection route, lightpath and link levels. The model also addresses various factors that affect connection blocking probability. These factors include wavelength continuity constraint, channel continuity constraint and route dependence. The Erlang fixed-point approximation method is used to solve the analytical model. Numerical results show that analytical results match well with simulation results. We also evaluate the effect of the grooming policies, the number of virtual hops (lightpaths) within a connection route and the number of alternate paths on the performance of the grooming algorithm.
BibTeX:
@article{YSLR08a-osn,
  author = {W. Yao and Sahin, Gokhan and M. Li and Ramamurthy, Byrav},
  title = {Analysis of Multi-Hop Traffic Grooming in WDM Mesh Networks},
  journal = {Optical Switching and Networking},
  year = {2009},
  volume = {6},
  number = {1},
  pages = {64-75},
  url = {http://dx.doi.org/10.1016/j.osn.2008.09.001},
  doi = {http://dx.doi.org/10.1016/j.osn.2008.09.001}
}
Miao Wang, Xu, L. & Ramamurthy, B. (2008), "Channel-Aware Peer Selection in Multi-View Peer-to-Peer Multimedia Streaming", In Computer Communications and Networks, 2008. ICCCN '08 IPMC Workshop. Proceedings of 17th International Conference on.
Abstract: Motivated by the success of the Picture in Picture feature of the traditional TV, several commercial Peer-to-Peer MultiMedia Streaming (P2PMMS) applications now support the multi-view feature, with which a user can simultaneously watch multiple channels on its screen. This paper considers the peer selection problem in multi-view P2PMMS. This problem has been well studied in the traditional single-view P2PMMS; however, it becomes more complicated in multi-view P2PMMS, mainly due to the fact that a peer watching multiple channels joins multiple corresponding overlays. In this paper, we propose a novel peer selection algorithm, called Channel-Aware Peer Selection (CAPS), where a peer selects its neighboring peers based on the channel subscription of the system, in order to efficiently utilize the bandwidth of all peers in the system, especially those peers watching multiple channels. The results of a large-scale simulation with 10,000 peers and 4 channels shows that CAPS can significantly improve the system performance over the straightforward Random Peer Selection (RPS), which is widely used in single-view P2PMMS networks.
BibTeX:
@inproceedings{WaXR08-icccn,
  author = {Miao Wang and Lisong Xu and Byrav Ramamurthy},
  title = {Channel-Aware Peer Selection in Multi-View Peer-to-Peer Multimedia Streaming},
  booktitle = {Computer Communications and Networks, 2008. ICCCN '08 IPMC Workshop. Proceedings of 17th International Conference on},
  year = {2008},
  url = {http://dx.doi.org/10.1109/ICCCN.2008.ECP.137},
  doi = {http://dx.doi.org/10.1109/ICCCN.2008.ECP.137}
}
Y. Wang, G. Attebury & Ramamurthy, B. (2008), "Security in Wireless Sensor Networks", In Security in Wireless Mesh Networks. Auerbach Publications, CRC Press.
BibTeX:
@incollection{WaAtRa08BC-Security,
  author = {Y. Wang and G. Attebury and Byrav Ramamurthy},
  title = {Security in Wireless Sensor Networks},
  booktitle = {Security in Wireless Mesh Networks},
  publisher = {Auerbach Publications, CRC Press},
  year = {2008},
  note = {ISBN: 9780849382505},
  url = {http://www.crcpress.com/shopping_cart/products/product_detail.asp?sku=AU8250},
  doi = {978-0849382505}
}
Hou, J., Kalyanaraman, S., Sivalingam, K. & Ramamurthy, B. (2008), "MESSAGE FROM THE TECHNICAL CHAIR", In IEEE INFOCOM 2008. The 27th Conference on Computer Communications., pp. iv.
BibTeX:
@inproceedings{INFTPC08,
  author = {Jennifer Hou and Shiv Kalyanaraman and Krishna Sivalingam and Byrav Ramamurthy},
  title = {MESSAGE FROM THE TECHNICAL CHAIR},
  booktitle = {IEEE INFOCOM 2008. The 27th Conference on Computer Communications},
  journal = {IEEE INFOCOM 2008. The 27th Conference on Computer Communications.},
  year = {2008},
  pages = {iv},
  url = {http://dx.doi.org/10.1109/INFOCOM.2008.4},
  doi = {http://dx.doi.org/10.1109/INFOCOM.2008.4}
}
Z. Ouyang, Xu, L. & Ramamurthy, B. (2008), "A Partial Forwarding Scheme for Dynamic Window Resizing in Live P2P Streaming Systems", In GLOBECOM '08. IEEE Global Telecommunications Conference. New Orleans, LA, USA. November/December 2008., pp. 6.
BibTeX:
@inproceedings{OuXR08-globecom,
  author = {Z. Ouyang and Lisong Xu and Byrav Ramamurthy},
  title = {A Partial Forwarding Scheme for Dynamic Window Resizing in Live P2P Streaming Systems},
  booktitle = {GLOBECOM '08. IEEE Global Telecommunications Conference},
  year = {2008},
  pages = {6},
  url = {http://dx.doi.org/10.1109/GLOCOM.2008.ECP.440},
  doi = {http://dx.doi.org/10.1109/GLOCOM.2008.ECP.440}
}
Rowe, C., Oglesby, R., Ramamurthy, B. & Swanson, D. (2008), "Regional Climate Change and its impacts in the Great Plains Region: An end-to-end approach (poster paper)", In Nebraska State EPSCoR Conference. Lincoln, NE. October 2008.
BibTeX:
@inproceedings{RORS08--NSTD,
  author = {C. Rowe and R. Oglesby and Byrav Ramamurthy and David Swanson},
  title = {Regional Climate Change and its impacts in the Great Plains Region: An end-to-end approach (poster paper)},
  booktitle = {Nebraska State EPSCoR Conference},
  year = {2008}
}
Y. Xue, Ramamurthy, B. & Vuran, M.C. (2008), "A Service-Differentiated Real-Time Communication Scheme for Wireless Sensor Networks", In SenseApp '08: Third IEEE International Workshop on Practical Issues in Building Sensor Network Applications (held in conjunction with IEEE Local Computer Networks (LCN) 2008). Montreal, Canada. October 2008., pp. 748-755.
Abstract: Supporting end-to-end real-time communication is important for wireless sensor networks (WSNs) to acomplish the collaborative sensing tasks with specific timing constraints. However, without considering the unique constraints for WSNs, many existing real-time communication protocols prove to be infeasible for low-cost WSNs. In this paper, we propose a novel real-time communication scheme (RCS) to provide service-differentiated soft real-time guarantees for end-to-end communication in WSNs. We use hop-based geographic grouping to enable location awareness for sensor nodes with extremely low control overhead.We use dynamic forwarding with load-balanced receiver contention to provide a light-weight, yet efficient, routing technique, which can be easily adapted for duty cycle design. We use polling contention period based real-time MAC support to improve the service-differentiation granularity with better bandwidth utilization. The performance evaluation shows that our scheme can achieve low end-to-end latency, high on-time delivery ratio, fine services-differentiation granularity with load-balance for real-time traffic in unsynchronized low-cost WSNs.
BibTeX:
@inproceedings{XuRV08,
  author = {Y. Xue and Byrav Ramamurthy and Mehmet Can Vuran},
  title = {A Service-Differentiated Real-Time Communication Scheme for Wireless Sensor Networks},
  booktitle = {SenseApp '08: Third IEEE International Workshop on Practical Issues in Building Sensor Network Applications (held in conjunction with IEEE Local Computer Networks (LCN) 2008)},
  year = {2008},
  pages = {748-755},
  url = {http://dx.doi.org/10.1109/LCN.2008.4664276},
  doi = {http://dx.doi.org/10.1109/LCN.2008.4664276}
}
Darwazeh, I. & Ramamurthy, B. (2008), "Message from the General Co-Chairs", In BROADNETS 2008. 5th International Conference on Broadband Communications, Networks and Systems. September 2008. IEEE.
BibTeX:
@inproceedings{Broadnets2008,
  author = {Izzat Darwazeh and Ramamurthy, Byrav},
  title = {Message from the General Co-Chairs},
  booktitle = {BROADNETS 2008. 5th International Conference on Broadband Communications, Networks and Systems},
  publisher = {IEEE},
  year = {2008},
  url = {http://dx.doi.org/10.1109/BROADNETS.2008.4769018},
  doi = {http://dx.doi.org/10.1109/BROADNETS.2008.4769018}
}
J. Ghoshal, M. Wang, Ramamurthy, B. & Xu, L. (2008), "Variable Neighbor Selection in Live Peer-to-Peer Multimedia Streaming Networks (poster paper)", In Broadnets 2008: Fifth International Conference on Broadband Communications, Networks and Systems. London, U.K.. September 2008., pp. 344-346.
Abstract: Data-driven (or swarming based) streaming is one of the popular ways to distribute live multimedia streaming traffic over peer-to-peer (P2P) networks. The efficiency and user satisfaction highly depend on the constructed overlays. The common neighbor selection algorithms in existing overlay construction schemes usually randomly select a fixed number of neighbors which satisfy the selection requirements, such as end-to-end delay or a peerpsilas sojourn time. However, this fixed random neighbor-selection algorithm (FRNS) neglects the peerspsila upload bandwidth heterogeneity and therefore, the upload bandwidth cannot be efficiently used. In this paper, we propose a variable random neighbor-selection (VRNS) scheme to alleviate the problems due to bandwidth heterogeneity, and in which the number of neighbors with different upload bandwidths is dynamically determined by the statistical bandwidth information of the system. Our proposed scheme is shown to outperform FRNS based upon a large volume of carefully designed simulations.
BibTeX:
@inproceedings{GWRX08,
  author = {J. Ghoshal and M. Wang and Byrav Ramamurthy and Lisong Xu},
  title = {Variable Neighbor Selection in Live Peer-to-Peer Multimedia Streaming Networks (poster paper)},
  booktitle = {Broadnets 2008: Fifth International Conference on Broadband Communications, Networks and Systems},
  year = {2008},
  pages = {344-346},
  url = {http://dx.doi.org/10.1109/BROADNETS.2008.4769101},
  doi = {http://dx.doi.org/10.1109/BROADNETS.2008.4769101}
}
Y. Wang, Ramamurthy, B., Y. Xue & X. Zou (2008), "A Security Framework for Wireless Sensor Networks Utilizing a Unique Session Key", In Broadnets 2008: Fifth International Conference on Broadband Communications, Networks and Systems. London, U.K.. September 2008., pp. 487-494.
Abstract: Key management is a core mechanism to ensure the security of applications and network services in wireless sensor networks. It includes two aspects: key distribution and key revocation. Many key management protocols have been specifically designed for wireless sensor networks. However, most of the key management protocols focus on the establishment of the required keys or the removal of the compromised keys. The design of these key management protocols does not consider the support of higher level security applications. When the applications are integrated later in sensor networks, new mechanisms must be designed. In this paper, we propose a security framework, uKeying, for wireless sensor networks. This framework can be easily extended to support many security applications. It includes three components: a security mechanism to provide secrecy for communications in sensor networks, an efficient session key distribution scheme, and a centralized key revocation scheme. The proposed framework does not depend on a specific key distribution scheme and can be used to support many security applications, such as secure group communications. Our analysis shows that the framework is secure, efficient, and extensible. The simulation and results also reveal for the first time that a centralized key revocation scheme can also attain a high efficiency.
BibTeX:
@inproceedings{WRXZ08,
  author = {Y. Wang and Byrav Ramamurthy and Y. Xue and X. Zou},
  title = {A Security Framework for Wireless Sensor Networks Utilizing a Unique Session Key},
  booktitle = {Broadnets 2008: Fifth International Conference on Broadband Communications, Networks and Systems},
  year = {2008},
  pages = {487-494},
  url = {http://dx.doi.org/10.1109/BROADNETS.2008.4769130},
  doi = {http://dx.doi.org/10.1109/BROADNETS.2008.4769130}
}
Ramamurthy, B. (2008), "Proceedings of the ICCCN 2008 Conference Program", In ICCCN 2008. The 17th International Conference on Computer Communications and Networks. August 2008.
BibTeX:
@inproceedings{ICCCN08,
  author = {Ramamurthy, Byrav},
  title = {Proceedings of the ICCCN 2008 Conference Program},
  booktitle = {ICCCN 2008. The 17th International Conference on Computer Communications and Networks},
  journal = {Proceedings, ICCCN 2008 Conference. The 17th International Conference on Computer Communications and Networks},
  year = {2008},
  url = {http://dx.doi.org/10.1109/ICCCN.2008.ECP.4},
  doi = {http://dx.doi.org/10.1109/ICCCN.2008.ECP.4}
}
Ramamurthy, B. (2008), "Dynamic Grooming Algorithms", In Traffic Grooming for Optical Networks: Foundations, Techniques and Frontiers (Optical Networks)., Hardcover., August, 2008. Springer.
Abstract: Traffic grooming is the name given to a family of optical network design problems that has attracted significant attention from both academia and industry in the last decade or so. The huge bandwidth of fiber optical networking is much larger than the typical bandwidth demands experienced by network service providers. This mismatch creates a need for multiplexing the low rate traffic demands into optical wavelength channels, but this requires costly electronic switching equipment, potentially offsetting the benefit of cheap optical transport. Traffic grooming refers to network design and resource allocation algorithms that can enable cost-efficient use of both network bandwidth and electronic switching. Due to the increasing bandwidth of optical communication on the one hand, and the growing variety of traffic demand magnitudes on the other, traffic grooming has grown from a narrow research area to a mainstream requirement for real world practitioners. This book presents the practical motivation, theoretical description, and extant techniques for traffic grooming in optical networks. The description of the various topics of research will be authored by leading researchers in this area, and will contain comprehensive description of related literature for each area. This book is intended to be a definitive reference and text for traffic grooming both for the practitioner in industry and the student in academia.
BibTeX:
@incollection{InDuKR08,
  author = {Ramamurthy, Byrav},
  title = {Dynamic Grooming Algorithms},
  booktitle = {Traffic Grooming for Optical Networks: Foundations, Techniques and Frontiers (Optical Networks)},
  publisher = {Springer},
  year = {2008},
  note = {ISBN:0387745173},
  url = {http://www.springer.com/engineering/signals/book/978-0-387-74517-6},
  doi = {978-0387745176}
}
W. Yao & Ramamurthy, B. (2008), "Rerouting schemes for dynamic traffic grooming in optical WDM networks", Computer Networks., July, 2008. Vol. 52(10), pp. 1891-1904.
Abstract: Traffic grooming in optical WDM mesh networks is a two-layer routing problem to effectively pack low-rate connections onto high-rate lightpaths, which, in turn, are established on wavelength links. The objective of traffic grooming is to improve resource efficiency. However, resource contention between lightpaths and connections may result in inefficient resource usage or even the blocking of some connections. In this work, we employ a rerouting approach to alleviate resource inefficiency and improve the network throughput under a dynamic traffic model. We propose two rerouting schemes, rerouting at lightpath level (RRLP) and rerouting at connection level (RRCON) and a qualitative comparison is made between the two. We also propose two heuristic rerouting algorithms, namely the critical-wavelength-avoiding one-lightpath-limited (CWA-1L) rerouting algorithm and the critical-lightpath-avoiding one-connection-limited (CLA-1C) rerouting algorithm, which are based on the two rerouting schemes. Simulation results show that rerouting reduces the blocking probability of connections significantly.
BibTeX:
@article{YaRa08cnet,
  author = {W. Yao and Ramamurthy, Byrav},
  title = {Rerouting schemes for dynamic traffic grooming in optical WDM networks},
  journal = {Computer Networks},
  year = {2008},
  volume = {52},
  number = {10},
  pages = {1891--1904},
  url = {http://dx.doi.org/10.1016/j.comnet.2008.02.027},
  doi = {http://dx.doi.org/10.1016/j.comnet.2008.02.027}
}
Saradhi, C.V., Ramamurthy, B., Schupke, D.A. & Oki, E. (2008), "Guest editorial - Multidomain optical networks: issues and challenges", IEEE Communications Magazine., June, 2008. Vol. 46(6), pp. 76-77.
Abstract: The eight articles in this feature topic highlight current work on interconnecting multiple optical domains and identify open challenges in deploying applications across multiple carriers' domains.
BibTeX:
@article{SRSO08,
  author = {Saradhi, C. V. and Ramamurthy, B. and Schupke, D. A. and Oki, E.},
  title = {Guest editorial - Multidomain optical networks: issues and challenges},
  journal = {IEEE Communications Magazine},
  year = {2008},
  volume = {46},
  number = {6},
  pages = {76--77},
  url = {http://dx.doi.org/10.1109/MCOM.2008.4539469},
  doi = {http://dx.doi.org/10.1109/MCOM.2008.4539469}
}
Y. Wang, Ramamurthy, B. & Y. Xue (2008), "A Key Management Protocol for Wireless Sensor Networks with Multiple Base Stations", In ICC '08. IEEE International Conference on Communications. May 2008., pp. 1625-1629.
Abstract: Most of the proposed key management protocols for wireless sensor networks (WSNs) in the literature assume that a single base station is used and that the base station is trustworthy. However, there are applications in which multiple base stations are used and the security of the base stations must be considered. This paper investigates a key management protocol in wireless sensor networks which include multiple base stations. We consider the situations in which both the base stations and the sensor nodes can be compromised. The proposed key management protocol, mKeying, includes two schemes, a key distribution scheme, mKeyDist, supporting multiple base stations in the network, and a key revocation scheme, mKeyRev, used to efficiently remove the compromised nodes from the network. Our analyses show that the proposed protocol is efficient and secure against the compromise of the base stations and the sensor nodes.
BibTeX:
@inproceedings{WaRX08icc,
  author = {Y. Wang and Ramamurthy, B. and Y. Xue},
  title = {A Key Management Protocol for Wireless Sensor Networks with Multiple Base Stations},
  booktitle = {ICC '08. IEEE International Conference on Communications},
  journal = {ICC '08. IEEE International Conference on Communications},
  year = {2008},
  pages = {1625--1629},
  url = {http://dx.doi.org/10.1109/ICC.2008.314},
  doi = {http://dx.doi.org/10.1109/ICC.2008.314}
}
Y. Xue, Ramamurthy, B. & Y. Wang (2008), "Providing Reliable Data Transport for Dynamic Event Sensing in Wireless Sensor Networks", In ICC '08. IEEE International Conference on Communications. May 2008., pp. 3146-3150.
Abstract: In this paper, we propose a loss tolerant reliable (LTR) data transport mechanism for dynamic event sensing (LT-RES) in WSNs. In LTRES, a reliable event sensing requirement at the transport layer is dynamically determined by the sink. A distributed source rate adaptation mechanism is designed, incorporating a loss rate based lightweight congestion control mechanism, to regulate the data traffic injected into the network so that the reliability requirement can be satisfied. An equation based fair rate control algorithm is used to improve the fairness among the LTRES flows sharing the congestion path. The performance evaluations show that LTRES can provide LTR data transport service for multiple events with short convergence time, low lost rate and high overall bandwidth utilization.
BibTeX:
@inproceedings{XuRW08icc,
  author = {Y. Xue and Ramamurthy, B. and Y. Wang},
  title = {Providing Reliable Data Transport for Dynamic Event Sensing in Wireless Sensor Networks},
  booktitle = {ICC '08. IEEE International Conference on Communications},
  journal = {ICC '08. IEEE International Conference on Communications},
  year = {2008},
  pages = {3146--3150},
  url = {http://dx.doi.org/10.1109/ICC.2008.592},
  doi = {http://dx.doi.org/10.1109/ICC.2008.592}
}
Ramakrishnan, K.K. & Ramamurthy, B. (2008), "Proceedings of the Mini-Conference Program", In INFOCOM 2008. The 27th IEEE Conference on Computer Communications. April 2008., pp. vi.
BibTeX:
@inproceedings{INFMINITPC08,
  author = {Ramakrishnan, K. K. and Ramamurthy, Byrav},
  title = {Proceedings of the Mini-Conference Program},
  booktitle = {INFOCOM 2008. The 27th IEEE Conference on Computer Communications},
  journal = {Proceedings, INFOCOM 2008 Mini-Conference. The 27th IEEE Conference on Computer Communications},
  year = {2008},
  pages = {vi},
  url = {http://dx.doi.org/10.1109/INFOCOM.2008.5},
  doi = {http://dx.doi.org/10.1109/INFOCOM.2008.5}
}
L. Shen, X. Yang & Ramamurthy, B. (2008), "A load-balancing spare capacity reallocation approach in the next-generation SONET metro networks", Optical Switching and Networking., In Special Section: Photonics in Switching 2006., March, 2008. Vol. 5(1), pp. 38-50.
Abstract: The next-generation SONET metro network is evolving into a service-rich infrastructure. At the edge of such a network, multiservice provisioning platforms (MSPPs) provide efficient data mapping enabled by Generic Framing Procedure (GFP) and Virtual Concatenation (VC). The core of the network tends to be a meshed architecture equipped with Multi-service Switches (MSSs). In the context of these emerging technologies, we propose a load-balancing spare capacity reallocation approach to improve network utilization in the next-generation SONET metro networks. Using our approach, carriers can postpone network upgrades, resulting in increased revenue with reduced capital expenditures (CAPEX). For the first time, we consider the spare capacity reallocation problem from a capacity upgrade and network planning perspective. Our approach can operate in the context of shared-path protection (with backup multiplexing) because it reallocates spare capacity without disrupting working services. Unlike previous spare capacity reallocation approaches which aim at minimizing total spare capacity, our load-balancing approach minimizes the network load vector (NLV), which is a novel metric that reflects the network load distribution. Because NLV takes into consideration both uniform and non-uniform link capacity distribution, our approach can benefit both uniform and non-uniform networks. We develop a greedy load-balancing spare capacity reallocation (GLB-SCR) heuristic algorithm to implement this approach. Our experimental results show that GLB-SCR outperforms a previously proposed algorithm (SSR) in terms of established connection capacity and total network capacity in both uniform and non-uniform networks.
BibTeX:
@article{ShYR08osn,
  author = {L. Shen and X. Yang and Ramamurthy, Byrav},
  title = {A load-balancing spare capacity reallocation approach in the next-generation SONET metro networks},
  booktitle = {Special Section: Photonics in Switching 2006},
  journal = {Optical Switching and Networking},
  year = {2008},
  volume = {5},
  number = {1},
  pages = {38--50},
  url = {http://dx.doi.org/10.1016/j.osn.2007.11.002},
  doi = {http://dx.doi.org/10.1016/j.osn.2007.11.002}
}
R.K. Balachandran, X. Zou, Ramamurthy, B., Thukral, A. & Variyam, V.N. (2007), "An efficient and attack-resistant key agreement scheme for secure group communications in mobile ad-hoc networks", Wireless Communications and Mobile Computing (WCMC)., December, 2007.
Abstract: As a result of the growing popularity of wireless networks, in particular mobile ad hoc networks (MANET), security over such networks has become very important. Trust establishment, key management, authentication, and authorization are important areas that need to be thoroughly researched before security in MANETs becomes a reality. This work studies the problem of secure group communications (SGCs) and key management over MANETs. It identifies the key features of any SGC scheme over such networks. AUTH-CRTDH, an efficient key agreement scheme with authentication capability for SGC over MANETs, is proposed. Compared to the existing schemes, the proposed scheme has many desirable features such as contributory and efficient computation of group key, uniform work load for all members, few rounds of rekeying, efficient support for user dynamics, key agreement without member serialization and defense against the Man-in-the-Middle attack, and the Least Common Multiple (LCM) attack. These properties make the proposed scheme well suited for MANETs. The implementation results show that the proposed scheme is computationally efficient and scales well to a large number of mobile users.
BibTeX:
@article{BZRT08--NSTD,
  author = {R. K. Balachandran and X. Zou and Byrav Ramamurthy and Amandeep Thukral and Vinodchandran N. Variyam},
  title = {An efficient and attack-resistant key agreement scheme for secure group communications in mobile ad-hoc networks},
  journal = {Wireless Communications and Mobile Computing (WCMC)},
  year = {2007},
  url = {http://www.cs.iupui.edu/~xkzou/Papers/WCMC-AUTH-CRTDH.pdf},
  doi = {http://dx.doi.org/10.1002/wcm.575}
}
M. Li & Ramamurthy, B. (2007), "Dedicated path protection for waveband switching in WDM networks (invited paper)", In Broadnets 2007: Fourth International Conference on Broadband Communications, Networks and Systems. September 2007., pp. 584-593.
Abstract: This paper considers the problem of dedicated path-protection in a wavelength-division multiplexing (WDM) mesh network with waveband switching (WBS) functionality under shared risk link group (SRLG) constraints. Two protection schemes are proposed, namely the Protecting-waveBand-At-waveBand-Level-only (PBABL) and the Mixed-Protection-At-waveBand-and-Wavelength-Level (MPABWL). The PBABL protects each working waveband-path by a backup waveband-path. While the MPABWL protects each working waveband-path by either a backup waveband-path or multiple backup lightpaths. The performances of the two protection schemes in terms of gained revenue and cost saving are studied and compared. Integer linear programming (ILP) formulations are presented to solve the problems for each protection scheme. Numerical results of the ILPs and the experimental results of previously proposed heuristics are presented, which show that both heuristics can obtain optimum solutions. According to the results, under heavy load traffic the MPABWL scheme provides solutions with higher revenues than the PBABL scheme does. Under light load traffic, where network resources are sufficient to accommodate all the traffics, the PBABL scheme leads to less switching and transmission costs than the MPABWL scheme does.
BibTeX:
@inproceedings{LiRa07broadnets-Dedicated,
  author = {M. Li and Ramamurthy, Byrav},
  title = {Dedicated path protection for waveband switching in WDM networks (invited paper)},
  booktitle = {Broadnets 2007: Fourth International Conference on Broadband Communications, Networks and Systems},
  journal = {Broadnets 2007. Fourth International Conference on Broadband Communications, Networks and Systems},
  year = {2007},
  pages = {584--593},
  url = {http://dx.doi.org/10.1109/BROADNETS.2007.4550487},
  doi = {http://dx.doi.org/10.1109/BROADNETS.2007.4550487}
}
Y. Wang & Ramamurthy, B. (2007), "A key management protocol for hybrid wireless sensor networks (poster paper)", In Broadnets 2007: Fourth International Conference on Broadband Communications, Networks and Systems. September 2007., pp. 303-305.
BibTeX:
@inproceedings{WaRa07bnets,
  author = {Y. Wang and Ramamurthy, Byrav},
  title = {A key management protocol for hybrid wireless sensor networks (poster paper)},
  booktitle = {Broadnets 2007: Fourth International Conference on Broadband Communications, Networks and Systems},
  journal = {Broadnets 2007. Fourth International Conference on Broadband Communications, Networks and Systems},
  year = {2007},
  pages = {303--305},
  url = {http://dx.doi.org/10.1109/BROADNETS.2007.4550443},
  doi = {http://dx.doi.org/10.1109/BROADNETS.2007.4550443}
}
A. Todimala & Ramamurthy, B. (2007), "A scalable approach for survivable virtual topology routing in optical WDM networks", IEEE Journal on Selected Areas in Communications., In IEEE Journal on Selected Areas in Communications (JSAC)., August, 2007. Vol. 25(6), pp. 63-69.
Abstract: The survivable virtual topology routing problem is to route a virtual topology graph on a optical fiber physical topology such that the virtual topology remains connected when failures occur in the physical topology. In this work we study the problem of survivable virtual topology routing under single node/SRLG (Shared Risk Link Group) failure model. We prove that the survivable virtual topology routing problem under node/SRLG failures is NP-complete. We present an improved integer linear programming (ILP) formulation for computing the survivable routing of a virtual topology graph. However, ILP is not scalable when the network size scales more than a few tens of nodes. In this work, we present sub-classes of graphs which more accurately model an actual network and for which a survivable routing can be easily computed solving an ILP. We successfully computed the survivable routing of virtual topologies belonging to these sub-classes against link/SRLG failures for topologies of size up to 24 nodes.
BibTeX:
@article{ToRa07jsac,
  author = {A. Todimala and Ramamurthy, B.},
  title = {A scalable approach for survivable virtual topology routing in optical WDM networks},
  booktitle = {IEEE Journal on Selected Areas in Communications (JSAC)},
  journal = {IEEE Journal on Selected Areas in Communications},
  year = {2007},
  volume = {25},
  number = {6},
  pages = {63--69},
  url = {http://dx.doi.org/10.1109/JSAC-OCN.2007.020605},
  doi = {http://dx.doi.org/10.1109/JSAC-OCN.2007.020605}
}
Y. Wang & Ramamurthy, B. (2007), "Layered Clustering Communication Protocol for Wireless Sensor Networks", In ICCCN 2007: 16th International Conference on Computer Communications and Networks. August 2007., pp. 844-849.
Abstract: In this paper, we propose a layered clustering hierarchy (LCH) communication protocol for wireless sensor networks (WSNs). The design of LCH has two goals: scalability and energy-efficiency. In LCH, the sensor nodes are organized as a layered clustering structure. Each layer runs a distributed clustering protocol. By randomizing the rotation of cluster heads in each layer, the energy load is distributed evenly across sensors in the network. Our simulations show that LCH is effective in densely deployed sensor networks. On average, 70% of live sensor nodes are involved directly in the clustering communication hierarchy. Moreover, the simulations also show that the energy load and dead nodes are distributed evenly over the network. As studies prove that the performance of LCH depends mainly on the distributed clustering protocol, the location of cluster heads and cluster size are two critical factors in the design of LCH.
BibTeX:
@inproceedings{WaRa07icccn,
  author = {Y. Wang and Ramamurthy, B.},
  title = {Layered Clustering Communication Protocol for Wireless Sensor Networks},
  booktitle = {ICCCN 2007: 16th International Conference on Computer Communications and Networks},
  journal = {ICCCN 2007. 16th International Conference on Computer Communications and Networks},
  year = {2007},
  pages = {844--849},
  url = {http://dx.doi.org/10.1109/ICCCN.2007.4317923},
  doi = {http://dx.doi.org/10.1109/ICCCN.2007.4317923}
}
L. Shen, X. Yang, A. Todimala & Ramamurthy, B. (2007), "A Two-phase Approach for Dynamic Lightpath Scheduling in WDM Optical Networks", In ICC '07. IEEE International Conference on Communications. May 2007., pp. 2412-2417.
Abstract: Lightpath scheduling is an important capability in next-generation wavelength-division multiplexing (WDM) optical networks to reserve resources in advance for a specified time period while provisioning end-to-end lightpaths. In a dynamic environment, the end user requests for dynamic scheduled lightpath demands (D-SLDs) need to be serviced without the knowledge of future requests. Even though the starting time of the request may be hours or days from the current time, the end-user however expects a quick response as to whether the request could be satisfied. We propose a two- phase approach to dynamically schedule and provision D-SLDs. In the first phase, termed the deterministic lightpath scheduling phase, upon arrival of a lightpath request, the network control plane schedules a path with guaranteed resources so that the user can get a quick response with a deterministic lightpath schedule. In the second phase, termed the lightpath re-optimization phase, we re-provision some already scheduled lightpaths to re-optimize for improving network performance. We study two re- optimization scenarios to reallocate network resources while maintaining the existing lightpath schedules. Experimental results show that our proposed two-phase dynamic lightpath scheduling approach can greatly reduce network blocking.
BibTeX:
@inproceedings{SYTR07icc,
  author = {L. Shen and X. Yang and A. Todimala and Ramamurthy, B.},
  title = {A Two-phase Approach for Dynamic Lightpath Scheduling in WDM Optical Networks},
  booktitle = {ICC '07. IEEE International Conference on Communications},
  journal = {ICC '07. IEEE International Conference on Communications},
  year = {2007},
  pages = {2412--2417},
  url = {http://dx.doi.org/10.1109/ICC.2007.405},
  doi = {http://dx.doi.org/10.1109/ICC.2007.405}
}
Y. Wang & Ramamurthy, B. (2007), "Group Rekeying Schemes for Secure Group Communication in Wireless Sensor Networks", In ICC '07. IEEE International Conference on Communications. May 2007., pp. 3419-3424.
Abstract: Wireless sensor networks are promising solutions for many applications. However, wireless sensor nodes suffer from many constraints such as low computation capability, small memory, limited energy resources, and so on. Grouping is an important technique to localize computation and reduce communication overhead in wireless sensor networks. In this paper, we use grouping to refer to the process of combining a set of sensor nodes with similar properties. We propose two centralized group rekeying (CGK) schemes for secure group communication in sensor networks. The lifetime of a group is divided into three phases, i.e., group formation, group maintenance, and group dissolution. We demonstrate how to set up the group and establish the group key in each phase. Our analysis shows that the proposed two schemes are computationally efficient and secure.
BibTeX:
@inproceedings{WaRa07icc,
  author = {Y. Wang and Ramamurthy, B.},
  title = {Group Rekeying Schemes for Secure Group Communication in Wireless Sensor Networks},
  booktitle = {ICC '07. IEEE International Conference on Communications},
  journal = {ICC '07. IEEE International Conference on Communications},
  year = {2007},
  pages = {3419--3424},
  url = {http://dx.doi.org/10.1109/ICC.2007.566},
  doi = {http://dx.doi.org/10.1109/ICC.2007.566}
}
Y. Wang, Ramamurthy, B. & X. Zou (2007), "KeyRev: An Efficient Key Revocation Scheme for Wireless Sensor Networks", In ICC '07. IEEE International Conference on Communications. May 2007., pp. 1260-1265.
Abstract: Key management is a core mechanism to ensure the security of applications and network services in wireless sensor networks. It includes two aspects: key distribution and key revocation. Key distribution has been extensively studied in the context of sensor networks. However, key revocation has received relatively little attention. Existing key revocation schemes can be divided into two categories: centralized key revocation scheme and distributed key revocation scheme. In this paper, we first summarize the current key revocation schemes for sensor networks. Then, we propose an efficient centralized key revocation scheme, KeyRev, for wireless sensor networks. Unlike most proposed key revocation schemes focusing on removing the compromised keys, we propose to use key updating techniques to obsolesce the keys owned by the compromised sensor nodes and thus remove the nodes from the network. Our analyses show that the KeyRev scheme is secure inspite of not removing the pre-distributed key materials at compromised sensor nodes. Simulation results also indicate that the KeyRev scheme is scalable and performs very well in wireless sensor networks.
BibTeX:
@inproceedings{WaRZ07icc,
  author = {Y. Wang and Ramamurthy, B. and X. Zou},
  title = {KeyRev: An Efficient Key Revocation Scheme for Wireless Sensor Networks},
  booktitle = {ICC '07. IEEE International Conference on Communications},
  journal = {ICC '07. IEEE International Conference on Communications},
  year = {2007},
  pages = {1260--1265},
  url = {http://dx.doi.org/10.1109/ICC.2007.213},
  doi = {http://dx.doi.org/10.1109/ICC.2007.213}
}
Ghani, N. & Ramamurthy, B. (2007), "Message from the Chairs", In IEEE INFOCOM High-Speed Networks (HSN) Workshop. Piscataway, N.J.. April 2007.
BibTeX:
@inproceedings{1273,
  author = {Ghani, Nasir and Ramamurthy, Byrav},
  title = {Message from the Chairs},
  booktitle = {IEEE INFOCOM High-Speed Networks (HSN) Workshop},
  year = {2007},
  url = {http://dx.doi.org/10.1109/HSNW.2007.4290533},
  doi = {http://dx.doi.org/10.1109/HSNW.2007.4290533}
}
A. Todimala & Ramamurthy, B. (2007), "Algorithms for Intermediate Waveband Switching in Optical WDM Mesh Networks", In IEEE INFOCOM High-Speed Networks (HSN) Workshop. April 2007., pp. 21-25.
Abstract: Waveband switching is a technique that allows multiple wavelengths to be switched together as a single unit. Waveband switching technique has been proven to reduce the switch sizes considerably in large networks. Aggregation of wavelengths into wavebands and dis-aggregation of wavebands back to wavelengths can be done at end-nodes or intermediate-nodes. Most of the research on waveband switching has considered source-to-end switching. In intermediate waveband switching, aggregation and/or dis-aggregation can be done at an intermediate node. In the context of intermediate waveband switching, the problem of grooming wavelengths such that the number of ports saved is maximized is non-trivial. Recent research which considered intermediate waveband switching focused on routing and wavelength assignment problem such that the port saving is maximized. In this work we focus on the problem of intermediate waveband switching considering static traffic and assuming that routing and wavelength assignment is known. We define two intermediate waveband grooming polices, intermediate-to-destination waveband switching (ITD-WBS) and both-end-to-intermediate waveband switching (BETI-WBS), depending on where along the path aggregation/disaggregation of wavebands is done. We present greedy algorithms to compute wavebands for the two intermediate waveband grooming polices and analyze their computational complexities.
BibTeX:
@inproceedings{ToRa07hsn,
  author = {A. Todimala and Ramamurthy, B.},
  title = {Algorithms for Intermediate Waveband Switching in Optical WDM Mesh Networks},
  booktitle = {IEEE INFOCOM High-Speed Networks (HSN) Workshop},
  journal = {IEEE INFOCOM High-Speed Networks (HSN) Workshop},
  year = {2007},
  pages = {21--25},
  url = {http://dx.doi.org/10.1109/HSNW.2007.4290539},
  doi = {http://dx.doi.org/10.1109/HSNW.2007.4290539}
}
J. Feng, Z. Ouyang, Xu, L. & Ramamurthy, B. (2007), "Packet Reordering in High-Speed Networks and Its Impact on High-Speed TCP Variants", In PFLDnet 2007, Fifth International Workshop on Protocols for FAST Long-Distance Networks. February 2007., pp. 19-24.
Abstract: Several recent Internet measurement studies show that the higher the packet sending rate, the higher the packet reordering probability. This implies that recently proposed highspeed TCP variants are more likely to experience packet reordering than regular TCP in high-speed networks, since they are designed to achieve much higher throughput than regular TCP in these networks. In this paper, we study the characteristics of packet reordering in high-speed networks, and its impact on highspeed TCP variants. In addition, we evaluate the effectiveness of the existing reordering-tolerant TCP enhancements. Our simulation results demonstrate that high-speed TCP variants perform poorly in the presence of packet reordering, and existing reordering-tolerant algorithms can significantly improve the performance of high-speed TCP variants.
BibTeX:
@inproceedings{FOXR07pfldnet-Packet,
  author = {J. Feng and Z. Ouyang and Lisong Xu and Byrav Ramamurthy},
  title = {Packet Reordering in High-Speed Networks and Its Impact on High-Speed TCP Variants},
  booktitle = {PFLDnet 2007, Fifth International Workshop on Protocols for FAST Long-Distance Networks},
  year = {2007},
  pages = {19--24},
  url = {http://wil.cs.caltech.edu/pfldnet2007/paper/PacketReorderingFeng.pdf}
}
Y. Xue, Ramamurthy, B. & Lu, Y. (2006), "A distributed reliable data transport strategy for event based wireless sensor networks", In SenSys '06: 4th ACM International conference on Embedded networked sensor systems. New York, NY, USA. November 2006., pp. 407-408. ACM.
BibTeX:
@inproceedings{XuRL06sensys,
  author = {Y. Xue and Ramamurthy, Byrav and Lu, Ying},
  title = {A distributed reliable data transport strategy for event based wireless sensor networks},
  booktitle = {SenSys '06: 4th ACM International conference on Embedded networked sensor systems},
  publisher = {ACM},
  year = {2006},
  pages = {407--408},
  note = {ISBN: 1595933433},
  url = {http://portal.acm.org/citation.cfm?id=1182807.1182879},
  doi = {http://dx.doi.org/10.1145/1182807.1182879}
}
M. Li & Ramamurthy, B. (2006), "Heterogeneous waveband switching in wavelength division multiplexed networks based on autonomous clustering architecture [Invited]", OSA Journal of Optical Networking (JON)., September, 2006. Vol. 5(9), pp. 667-680. OSA.
Abstract: Adopting waveband switching (WBS) in backbone wavelength division multiplexed (WDM) networks is promising since it can reduce the network operational cost and the call blocking probability. However, upgrading the existing optical switching architecture requires time and money. Thus heterogeneous waveband switching (HeteroWBS) architecture would be desirable in such a system, where some nodes can support WBS functions and some cannot. We study the performance of HeteroWBS networks in terms of call blocking probability and cost savings under dynamically arriving traffic requests. We first investigate the effects of optical component developments on waveband switching in WDM networks. Various connection managements are then listed and analyzed. Next, to assist in the designing of efficient WBS algorithms, an autonomous clustering-based HeteroWBS (AS-HeteroWBS) architecture is proposed. The AS-HeteroWBS architecture clusters the network into multiple autonomous systems (ASs). An AS may contain some specific nodes that provide WBS functions for all the nodes in the AS. Based on the architecture, three HeteroWBS algorithms are proposed, namely, the autonomous heterogeneous WBS algorithm (AS-WBS), the autonomous source-limited heterogeneous WBS algorithm (AS-S-WBS), and the shortest-path-based heterogeneous WBS algorithm (SH-WBS). Our simulation results show that the HeteroWBS algorithms can achieve optimal cost savings while maintaining the same network throughput compared with the algorithm without WBS.
BibTeX:
@article{LiRa06jon,
  author = {M. Li and Ramamurthy, Byrav},
  title = {Heterogeneous waveband switching in wavelength division multiplexed networks based on autonomous clustering architecture [Invited]},
  journal = {OSA Journal of Optical Networking (JON)},
  publisher = {OSA},
  year = {2006},
  volume = {5},
  number = {9},
  pages = {667--680},
  url = {http://www.opticsinfobase.org/abstract.cfm?id=97969},
  doi = {http://dx.doi.org/10.1364/JON.5.000667}
}
Y. Wang & Ramamurthy, B. (2006), "A Centralized Group Rekeying Scheme for Secure Group Communication in Wireless Sensor Networks (poster)", In SecureComm 2006, Second International Conference on Security and Privacy in Communication Networks. Baltimore, MD. August 2006.
BibTeX:
@inproceedings{WaRa06scom-poster,
  author = {Y. Wang and Ramamurthy, B.},
  title = {A Centralized Group Rekeying Scheme for Secure Group Communication in Wireless Sensor Networks (poster)},
  booktitle = {SecureComm 2006, Second International Conference on Security and Privacy in Communication Networks},
  year = {2006},
  url = {http://0-ieeexplore.ieee.org.library.unl.edu:80/servlet/opac?punumber=4198788}
}
G. Attebury & Ramamurthy, B. (2006), "Router and Firewall Redundancy with OpenBSD and CARP", In ICC '06. IEEE International Conference on Communications. June 2006. Volume 1, pp. 146-151.
Abstract: As more reliance is placed on computing and networking systems, the need for redundancy increases. The Common Address Redundancy Protocol (CARP) protocol and OpenBSD's pfsync utility provide a means by which to implement redundant routers and firewalls. This paper details how CARP and pfsync work together to provide this redundancy and explores the performance one can expect from the open source solutions. Two experiments were run: one showing the relationship between firewall state creation and state synchronization traffic and the other showing how TCP sessions are transparently maintained in the event of a router failure. Discussion of these simulations along with background information gives an overview of how OpenBSD, CARP, and pfsync can provide redundant routers and firewalls for today's Internet.
BibTeX:
@inproceedings{AtRa06icc,
  author = {G. Attebury and Ramamurthy, B.},
  title = {Router and Firewall Redundancy with OpenBSD and CARP},
  booktitle = {ICC '06. IEEE International Conference on Communications},
  journal = {ICC '06. IEEE International Conference on Communications},
  year = {2006},
  volume = {1},
  pages = {146--151},
  url = {http://dx.doi.org/10.1109/ICC.2006.254719},
  doi = {http://dx.doi.org/10.1109/ICC.2006.254719}
}
S. Deshpande, A. Todimala, R.K. Balachandran, Ramamurthy, B., X. Zou & Vinodchandran, N.V. (2006), "A New Cryptographic Scheme for Securing Dynamic Conferences in Data Networks", In ICC '06. IEEE International Conference on Communications. June 2006. Volume 5, pp. 2310-2315.
Abstract: Dynamic conferencing refers to a scenario wherein any subset of users in a universe of users form a conference for sharing confidential information among themselves. The key distribution (KD) problem in dynamic conferencing is to compute a shared secret key for such a dynamically formed conference. In literature, the KD schemes for dynamic conferencing either are computationally unscalable or require communication among users, which is undesirable. The extended symmetric polynomial based dynamic conferencing scheme (ESPDCS) is one such KD scheme which has a high computational complexity that is universe size dependent. In this paper we present an enhancement to the ESPDCS scheme to develop a KD scheme called universe-independent SPDCS (UI-SPDCS) such that its complexity is independent of the universe size. However, the UI-SPDCS scheme does not scale with the conference size. We propose a relatively scalable KD scheme termed as DH-SPDCS that uses the UI-SPDCS scheme and the tree-based group Diffie-Hellman (TGDH) key exchange protocol. The proposed DH-SPDCS scheme provides a configurable trade-off between computation and communication complexity of the scheme.
BibTeX:
@inproceedings{Desh06icc,
  author = {S. Deshpande and A. Todimala and R.K. Balachandran and Ramamurthy, B. and X. Zou and Vinodchandran, N. V.},
  title = {A New Cryptographic Scheme for Securing Dynamic Conferences in Data Networks},
  booktitle = {ICC '06. IEEE International Conference on Communications},
  journal = {ICC '06. IEEE International Conference on Communications},
  year = {2006},
  volume = {5},
  pages = {2310--2315},
  url = {http://dx.doi.org/10.1109/ICC.2006.255114},
  doi = {http://dx.doi.org/10.1109/ICC.2006.255114}
}
M. Li & Ramamurthy, B. (2006), "Autonomous Clustering-Based Heterogeneous Waveband Switching in WDM Networks", In ICC '06. IEEE International Conference on Communications. June 2006. Volume 6, pp. 2587-2592.
Abstract: Employing waveband switching (WBS) in WDM networks can reduce the network operational cost and the call blocking probability. However, upgrading the existing optical switching architecture requires time and money. It is expected that a heterogeneous waveband switching (HeteroWBS) architecture would be desirable, where some nodes can support WBS functions and some cannot. We study the performance of HeteroWBS networks in terms of call blocking probability and cost savings under dynamic traffic requests. We propose an autonomous clustering-based HeteroWBS (AS-HeteroWBS) architecture to clusters the network into multiple autonomous systems (ASs). An AS may contain some specific nodes that provide WBS functions for all the nodes in the AS. Based on the architecture, three HeteroWBS algorithms are proposed. Our simulation results show that the HeteroWBS algorithms can achieve optimal cost savings while maintaining the same network throughput compared with the algorithm without WBS.
BibTeX:
@inproceedings{LiRa06icc,
  author = {M. Li and Ramamurthy, B.},
  title = {Autonomous Clustering-Based Heterogeneous Waveband Switching in WDM Networks},
  booktitle = {ICC '06. IEEE International Conference on Communications},
  journal = {ICC '06. IEEE International Conference on Communications},
  year = {2006},
  volume = {6},
  pages = {2587--2592},
  url = {http://dx.doi.org/10.1109/ICC.2006.255169},
  doi = {http://dx.doi.org/10.1109/ICC.2006.255169}
}
Y. Wang, Ramamurthy, B. & X. Zou (2006), "The Performance of Elliptic Curve Based Group Diffie-Hellman Protocols for Secure Group Communication over Ad Hoc Networks", In ICC '06. IEEE International Conference on Communications. June 2006. Volume 5, pp. 2243-2248.
Abstract: The security of the two party Diffie-Hellman key exchange protocol is currently based on the discrete logarithm problem (DLP). However, it can also be built upon the elliptic curve discrete logarithm problem (ECDLP). Most proposed secure group communication schemes employ the DLP-based Diffie-Hellman protocol. This paper proposes the ECDLP-based Diffie-Hellman protocols for secure group communication and evaluates their performance on wireless ad hoc networks. The proposed schemes are compared at the same security level with DLP-based group protocols under different channel conditions. Our experiments and analysis show that the Tree-based Group Elliptic Curve Diffie-Hellman (TGECDH) protocol is the best in overall performance for secure group communication among the four schemes discussed in the paper. Low communication overhead, relatively low computation load and short packets are the main reasons for the good performance of the TGECDH protocol.
BibTeX:
@inproceedings{WaRZ06icc,
  author = {Y. Wang and Ramamurthy, B. and X. Zou},
  title = {The Performance of Elliptic Curve Based Group Diffie-Hellman Protocols for Secure Group Communication over Ad Hoc Networks},
  booktitle = {ICC '06. IEEE International Conference on Communications},
  journal = {ICC '06. IEEE International Conference on Communications},
  year = {2006},
  volume = {5},
  pages = {2243--2248},
  url = {http://dx.doi.org/10.1109/ICC.2006.255104},
  doi = {http://dx.doi.org/10.1109/ICC.2006.255104}
}
M. Li & Ramamurthy, B. (2006), "Integrated Intermediate Waveband and Wavelength Switching for Optical WDM Mesh Networks", In INFOCOM 2006. The 25th IEEE International Conference on Computer Communications. April 2006., pp. 1-12.
Abstract: As wavelength-division multiplexing (WDM) evolves

towards practical applications in optical transport networks,

waveband switching (WBS) has been introduced to cut down

the operational costs and to reduce the complexities and sizes

of network components, e.g., optical cross-connects (OXCs).

This paper considers the routing, wavelength assignment and

waveband assignment (RWWBA) problem in a WDM network

supporting mixed waveband and wavelength switching. First, the

techniques supporting waveband switching are studied, where

a node architecture enabling mixed waveband and wavelength

switching is proposed. Second, to solve the RWWBA problem

with reduced switching costs and improved network throughput,

the cost savings and call blocking probabilities along intermediate

waveband-routes are analyzed. Our analysis reveals some

important insights about the cost savings and call blocking

probability in relation to the Þber capacity, the candidate path,

and the trafÞc load. Third, based on our analysis, an online

integrated intermediate WBS algorithm (IIWBS) is proposed.

IIWBS determines the waveband switching route for a call along

its candidate path according to the node connectivity, the link

utilization, and the path length information. In addition, the

IIWBS algorithm is adaptive to real network applications under

dynamic trafÞc requests. Finally, our simulation results show

that IIWBS outperforms a previous intermediate WBS algorithm

and RWA algorithms in terms of network throughput and cost

efÞciency.

BibTeX:
@inproceedings{LiRa06infocom,
  author = {M. Li and Ramamurthy, B.},
  title = {Integrated Intermediate Waveband and Wavelength Switching for Optical WDM Mesh Networks},
  booktitle = {INFOCOM 2006. The 25th IEEE International Conference on Computer Communications},
  journal = {INFOCOM 2006. 25th IEEE International Conference on Computer Communications},
  year = {2006},
  pages = {1--12},
  url = {http://dx.doi.org/10.1109/INFOCOM.2006.162},
  doi = {http://dx.doi.org/10.1109/INFOCOM.2006.162}
}
A. Todimala & Ramamurthy, B. (2006), "Approximation Algorithms for Survivable Multicommodity Flow Problems with Applications to Network Design", In INFOCOM 2006. 25th IEEE International Conference on Computer Communications. April 2006., pp. 1-12.
Abstract: Multicommodity ßow (MF) problems have a wide variety of applications

in areas such as VLSI circuit design, network design, etc., and are

therefore very well studied. The fractional MF problems are polynomial

time solvable while integer versions are NP-complete. However, exact

algorithms to solve the fractional MF problems have high computational

complexity. Therefore approximation algorithms to solve the fractional

MF problems have been explored in the literature to reduce their

computational complexity. Using these approximation algorithms and the

randomized rounding technique, polynomial time approximation

algorithms have been explored in the literature.

In the design of high-speed networks, such as optical wavelength

division multiplexing (WDM) networks, providing survivability carries

great signiÞcance. Survivability is the ability of the network to

recover from failures. It further increases the complexity of network

design and presents network designers with more formidable

challenges. In this work we formulate the survivable versions of the

MF problems. We build approximation algorithms for the survivable

multicommodity ßow (SMF) problems based on the framework of the

approximation algorithms for the MF problems presented in [1] and

[2]. We discuss applications of the SMF problems to solve survivable

routing in capacitated networks.

BibTeX:
@inproceedings{ToRa06infocom,
  author = {A. Todimala and Ramamurthy, B.},
  title = {Approximation Algorithms for Survivable Multicommodity Flow Problems with Applications to Network Design},
  booktitle = {INFOCOM 2006. 25th IEEE International Conference on Computer Communications},
  journal = {INFOCOM 2006. 25th IEEE International Conference on Computer Communications},
  year = {2006},
  pages = {1--12},
  url = {http://dx.doi.org/10.1109/INFOCOM.2006.92},
  doi = {http://dx.doi.org/10.1109/INFOCOM.2006.92}
}
X. Yang, L. Shen, A. Todimala, Ramamurthy, B. & Lehman, T. (2006), "An Efficient Scheduling Scheme for On-Demand Lightpath Reservations in Reconfigurable WDM Optical Networks", In Optical Fiber Communication Conference and Exposition and The National Fiber Optic Engineers Conference. March 2006., pp. 1-3. Optical Society of America.
Abstract: We propose an efficient scheduling scheme that optimizes advance-reserved lightpath services in reconfigurable WDM networks. A re-optimization approach is devised to reallocate network resources for dynamic service demands while keeping determined schedule unchanged.
BibTeX:
@inproceedings{Yang06ofc,
  author = {X. Yang and L. Shen and A. Todimala and Ramamurthy, Byrav and Lehman, Tom},
  title = {An Efficient Scheduling Scheme for On-Demand Lightpath Reservations in Reconfigurable WDM Optical Networks},
  booktitle = {Optical Fiber Communication Conference and Exposition and The National Fiber Optic Engineers Conference},
  publisher = {Optical Society of America},
  year = {2006},
  pages = {1--3},
  url = {http://www.opticsinfobase.org/abstract.cfm?id=107516}
}
M. Li & Ramamurthy, B. (2006), "A Generic Autonomous Clustering-Based Heterogeneous Waveband Switching Architecture in WDM Networks", In Optical Fiber Communication (OFC) Conference and Exposition and The National Fiber Optic Engineers Conference (NFOEC). March 2006., pp. 1-3. Optical Society of America.
Abstract: Heterogeneous waveband switching (HeteroWBS) in WDM networks reduces the network operational costs. We propose an autonomous clustering-based HeteroWBS architecture to support the design of efficient HeteroWBS algorithms under dynamic traffic requests in such a network.
BibTeX:
@inproceedings{LiRa06ofc,
  author = {M. Li and Ramamurthy, Byrav},
  title = {A Generic Autonomous Clustering-Based Heterogeneous Waveband Switching Architecture in WDM Networks},
  booktitle = {Optical Fiber Communication (OFC) Conference and Exposition and The National Fiber Optic Engineers Conference (NFOEC)},
  publisher = {Optical Society of America},
  year = {2006},
  pages = {1--3},
  url = {http://www.opticsinfobase.org/abstract.cfm?id=107471}
}
X. Zou, A. Thukral & Ramamurthy, B. (2006), "An authenticated key agreement protocol for mobile ad hoc networks", In Mobile Ad-hoc and Sensor Networks. Second International Conference, MSN 2006. (Lecture Notes in Computer Science Vol. 4325). Country of Publication: Germany, January, 2006. , pp. 509-520. Springer-Verlag.
Abstract: The growing popularity of wireless ad hoc networks has brought increasing attention to many security issues for such networks. A lot of research has been carried out in the areas of authentication and key management for such networks. However, due to lack of existing standards for such networks, most of the proposed schemes are based on different assumptions and are applicable only in specific environments. Recently Balachandran et al. proposed CRTDH (2005), a novel key agreement scheme for group communications in wireless ad hoc networks. The protocol has many desirable properties such as efficient computation of group key and support for high dynamics. However, the protocol does not discuss mutual authentication among the nodes and hence, suffers from two kinds of attacks: man-in-the-middle attack and least common multiple (LCM) attack. This paper identifies the problems with the current CRTDH scheme and discusses these attacks. AUTH-CRTDH, a modified key agreement protocol with authentication capability, is also presented. Results from extensive experiments that were run on the proposed protocol arid some other key agreement protocols including CRTDH are also discussed. It can be observed from the experiments that the new scheme is comparable with the CRTDH scheme and better than many other non-authenticated schemes in terms of performance
BibTeX:
@incollection{9296297,
  author = {X. Zou and A. Thukral and Ramamurthy, B.},
  title = {An authenticated key agreement protocol for mobile ad hoc networks},
  booktitle = {Mobile Ad-hoc and Sensor Networks. Second International Conference, MSN 2006. (Lecture Notes in Computer Science Vol. 4325)},
  publisher = {Springer-Verlag},
  year = {2006},
  pages = {509--520},
  url = {http://dx.doi.org/10.1007/11943952_43},
  doi = {http://dx.doi.org/10.1007/11943952_43}
}
Y. Wang, G. Attebury & Ramamurthy, B. (2006), "A survey of security issues in wireless sensor networks", IEEE Communications Surveys & Tutorials., In IEEE Communications Surveys & Tutorials., Second Quarter, 2006. Vol. 8(2), pp. 2-23.
Abstract: Wireless Sensor Networks (WSNs) are used in many applications in mil-

itary, ecological, and health-related areas. These applications often include

the monitoring of sensitive information such as enemy movement on the

battlefield or the location of personnel in a building. Security is therefore

important in WSNs. However, WSNs suffer from many constraints, includ-

ing low computation capability, small memory, limited energy resources,

susceptibility to physical capture, and the use of insecure wireless communi-

cation channels. These constraints make security in WSNs a challenge. In

this article we present a survey of security issues in WSNs. First we outline

the constraints, security requirements, and attacks with their corresponding

countermeasures in WSNs. We then present a holistic view of security

issues. These issues are classified into five categories: cryptography, key

management, secure routing, secure data aggregation, and intrusion detec-

tion. Along the way we highlight the advantages and disadvantages of vari-

ous WSN security protocols and further compare and evaluate these

protocols based on each of these five categories. We also point out the

open research issues in each subarea and conclude with possible future

research directions on security in WSNs.

BibTeX:
@article{WaAR06cst,
  author = {Y. Wang and G. Attebury and Ramamurthy, B.},
  title = {A survey of security issues in wireless sensor networks},
  booktitle = {IEEE Communications Surveys & Tutorials},
  journal = {IEEE Communications Surveys & Tutorials},
  year = {2006},
  volume = {8},
  number = {2},
  pages = {2--23},
  url = {http://dx.doi.org/10.1109/COMST.2006.315852},
  doi = {http://dx.doi.org/10.1109/COMST.2006.315852}
}
A. Todimala, Ramamurthy, B. & Vinodchandran, N.V. (2005), "On computing disjoint paths with dependent cost structure in optical networks", In BROADNETS 2005: 2nd International Conference on Broadband Networks. Volume 1, pp. 145-154.
Abstract: Providing fault tolerance against network failures in an optical WDM network is of prime importance. In this work we study the problem of computing optimal disjoint paths for providing shared protection in fully wavelength-convertible networks. We introduce and formalize the concept of dependent cost structure of a protection path on its working path and current network status. We formulate the problem of computing optimal disjoint paths for providing shared protection in fully wavelength-convertible networks as the problem of computing least-cost disjoint paths with dependent cost structure (LDP-DCS). We prove that LDP-DCS is NP-complete and is also hard to approximate. We present an iterative modified network-flow heuristic for the problem. We provide an approach to measure the optimality of the solution computed by the heuristic. Simulation results demonstrate the superior performance of our proposed heuristic in comparison to earlier heuristic approaches which did not consider the dependent cost structure.
BibTeX:
@inproceedings{ToRV05broadnets,
  author = {A. Todimala and Ramamurthy, Byrav and Vinodchandran, N. V.},
  title = {On computing disjoint paths with dependent cost structure in optical networks},
  booktitle = {BROADNETS 2005: 2nd International Conference on Broadband Networks},
  journal = {Broadnets 2005: 2nd International Conference on Broadband Networks},
  year = {2005},
  volume = {1},
  pages = {145--154},
  url = {http://dx.doi.org/10.1109/ICBN.2005.1589610},
  doi = {http://dx.doi.org/10.1109/ICBN.2005.1589610}
}
X. Zou & Ramamurthy, B. (2005), "A Simple Group Diffie-Hellman Key Agreement Protocol Without Member Serialization", In Computational and Information Science, Lecture Notes in Computer Science (LNCS). Vol. 3314/2005, pp. 725-731. Springer.
Abstract: Many group key agreement protocols (GKA) for secure group communication (SGC) based on the Diffie-Hellman key exchange principle have been proposed in literature. All of these protocols require member serialization and/or existence of a central entity. In this paper, we propose a simple group Diffie-Hellman key agreement protocol which removes these two limitations. Moreover, the new protocol needs minimum (two) rounds of rekeying process and efficiently support high dynamics.
BibTeX:
@incollection{Zou2005Simple,
  author = {X. Zou and Ramamurthy, Byrav},
  title = {A Simple Group Diffie-Hellman Key Agreement Protocol Without Member Serialization},
  booktitle = {Computational and Information Science, Lecture Notes in Computer Science (LNCS)},
  publisher = {Springer},
  year = {2005},
  volume = {3314/2005},
  pages = {725--731},
  url = {http://www.springerlink.com/content/j71lh7glwrrnau14}
}
M. Li, W. Yao & Ramamurthy, B. (2005), "A novel cost-efficient on-line intermediate waveband-switching scheme in WDM mesh networks", In GLOBECOM '05: IEEE Global Telecommunications Conference. Volume 4, pp. 1-5.
Abstract: Waveband switching (WBS) is an important technique to save switching and transmission cost in wavelength-division multiplexed (WDM) optical networks. A cost-efficient WBS scheme would enable network carriers to increase the network throughput (revenue) while achieving significant cost savings. We identify the critical factors that determine the WBS network throughput and switching cost and propose a novel intermediate waveband switching (IT-WBS) algorithm, called the minimizing-weighted-cost (MWC) algorithm. The MWC algorithm defines a cost for each candidate route of a call. By selecting the route with the smallest weighted cost, MWC balances between minimizing the call blocking probability and minimizing the network switching cost. Our simulations show that MWC outperforms other wavelength/waveband switching algorithms and can enhance the network throughput at a reduced cost.
BibTeX:
@inproceedings{LiYR05globecom,
  author = {M. Li and W. Yao and Ramamurthy, B.},
  title = {A novel cost-efficient on-line intermediate waveband-switching scheme in WDM mesh networks},
  booktitle = {GLOBECOM '05: IEEE Global Telecommunications Conference},
  journal = {GLOBECOM '05. IEEE Global Telecommunications Conference},
  year = {2005},
  volume = {4},
  pages = {1--5},
  url = {http://dx.doi.org/10.1109/GLOCOM.2005.1578020},
  doi = {http://dx.doi.org/10.1109/GLOCOM.2005.1578020}
}
M. Li, W. Yao & Ramamurthy, B. (2005), "Same-destination-intermediate grouping vs. end-to-end grouping for waveband switching in WDM mesh networks", In ICC 2005: IEEE International Conference on Communications. Volume 3, pp. 1807-1812.
Abstract: We investigate waveband switching (WBS) with different grouping strategies in wavelength-division multiplexing (WDM) mesh networks. End-to-end waveband switching (ETE-WBS) and same-destination-intermediate waveband switching (SD-IT-WBS) are analyzed and compared in terms of blocking probability and cost savings. First, an analytical model for ETE-WBS is proposed to determine the network blocking probability in a mesh network. For SD-IT-WBS, a simple waveband switching algorithm is presented. An analytical model to determine the network blocking probability is proposed for SD-IT-WBS based on the algorithm. The analytical results are validated by comparing with simulation results. Both results match well and show that ETE-WBS slightly outperforms SD-IT-WBS in terms of blocking probability. On the other hand, simulation results show that SD-IT-WBS outperforms ETE-WBS in terms of cost savings.
BibTeX:
@inproceedings{LiYR05icc,
  author = {M. Li and W. Yao and Ramamurthy, B.},
  title = {Same-destination-intermediate grouping vs. end-to-end grouping for waveband switching in WDM mesh networks},
  booktitle = {ICC 2005: IEEE International Conference on Communications},
  journal = {ICC 2005. IEEE International Conference on Communications},
  year = {2005},
  volume = {3},
  pages = {1807--1812},
  url = {http://dx.doi.org/10.1109/ICC.2005.1494653},
  doi = {http://dx.doi.org/10.1109/ICC.2005.1494653}
}
W. Yao & Ramamurthy, B. (2005), "Survivable traffic grooming in WDM mesh networks under SRLG constraints", In ICC 2005: IEEE International Conference on Communications. Volume 3, pp. 1751-1755.
Abstract: Survivable traffic grooming (STG) is a promising approach to provide reliable and resource-efficient multi-granularity connection services in optical networks. In this paper, we study the static STG problem in WDM mesh networks employing path protection at the lightpath level. To make connections survivable under various failures such as fiber cut and duct cut, we consider the general shared risk link group (SRLG) diverse routing constraints. In addition to providing the results from the integer linear programming (ILP) approach, we propose three efficient heuristics, namely separated grooming algorithm (SGA), integrated grooming algorithm (IGA) and tabu search grooming algorithm (TSGA). While SGA and IGA correspond to an overlay model and a peer model respectively, TSGA further improves SGA and IGA by incorporating the tabu search method. Numerical results show that the heuristics use much shorter running times to generate network throughputs close to those of the ILP formulations.
BibTeX:
@inproceedings{YaRa05icc-Survivable,
  author = {W. Yao and Ramamurthy, Byrav},
  title = {Survivable traffic grooming in WDM mesh networks under SRLG constraints},
  booktitle = {ICC 2005: IEEE International Conference on Communications},
  journal = {ICC 2005. IEEE International Conference on Communications},
  year = {2005},
  volume = {3},
  pages = {1751--1755},
  url = {http://dx.doi.org/10.1109/ICC.2005.1494642},
  doi = {http://dx.doi.org/10.1109/ICC.2005.1494642}
}
G. Hao, Vinodchandran, N.V., Ramamurthy, B. & X. Zou (2005), "A balanced key tree approach for dynamic secure group communication", In ICCCN 2005: 14th International Conference on Computer Communications and Networks., pp. 345-350.
Abstract: Logical key hierarchy (LKH) is a promising solution to handle group key distribution in secure group communication. Several recent studies have investigated different approaches to reduce the re-keying cost of LKH. For certain group communication applications, such as the subscription pay TV; a member's departure time is available when the member joins the group. The proposed scheme aims to improve the re-keying cost for such applications. It uses a combination of an AVL tree and a binary search tree called the leaving tree as the topology of its key tree. Both the AVL tree and the leaving tree are searchable by members' departure times. Our analysis shows that the average costs in terms of the number of key updates for the member join and leave are O(logn) and O(loglog n), respectively. Our simulation results show that the proposed scheme achieves better performance than other balanced tree based solutions.
BibTeX:
@inproceedings{HVRZ05icccn,
  author = {G. Hao and Vinodchandran, N. V. and Ramamurthy, Byrav and X. Zou},
  title = {A balanced key tree approach for dynamic secure group communication},
  booktitle = {ICCCN 2005: 14th International Conference on Computer Communications and Networks},
  journal = {ICCCN 2005. 14th International Conference on Computer Communications and Networks},
  year = {2005},
  pages = {345--350},
  url = {http://dx.doi.org/10.1109/ICCCN.2005.1523882},
  doi = {http://dx.doi.org/10.1109/ICCCN.2005.1523882}
}
W. Yao, Sahin, G., M. Li & Ramamurthy, B. (2005), "Analysis of multi-hop traffic grooming in WDM mesh networks", In Broadnets 2005: 2nd International Conference on Broadband Networks., pp. 165-174.
Abstract: Traffic grooming is an essential functionality of WDM optical networks to provision multi-granularity subwave-length connections. Depending on the number of lightpaths allowed in a connection route, traffic grooming can be classified as single-hop traffic grooming (SH-TG) and multi-hop traffic grooming (MH-TG). MH-TG is more general and resource-efficient than SH-TG, because it allows connections from different source-destination pairs to share the bandwidth of a lightpath. In this paper, we propose a MH-TG algorithm, namely the fixed-order multi-hop (FOMH) grooming algorithm, based on the fixed-alternate routing approach. We introduce the grooming node selection (GNS) problem in MH-TG and propose three grooming policies, namely exhaustive sequential (ES), limited-hop sequential (LHS) and load sharing (LS) policies, to address the GNS problem. Given that the analysis of MH-TG is a relatively unexplored area, we propose an analytical model to evaluate the blocking performance of MH-TG using FOMH and the LS grooming policy. To address the multi-layered routing and multi-rate connection characteristics of traffic grooming, we introduce a novel multi-level decomposition approach in our analytical model which decomposes traffic at four different levels, namely alternate path, connection route, lightpath and link levels. The Erlang fixed-point approximation method is used to solve the analytical model. Numerical results show that analytical results matches well with simulation results. We also evaluate the effect of the grooming policies, the number of virtual hops (lightpaths) within a connection route and the number of alternate paths on the performance of the grooming algorithm.
BibTeX:
@inproceedings{YSLR05broadnets,
  author = {W. Yao and Sahin, G. and M. Li and Ramamurthy, Byrav},
  title = {Analysis of multi-hop traffic grooming in WDM mesh networks},
  booktitle = {Broadnets 2005: 2nd International Conference on Broadband Networks},
  journal = {Broadnets 2005. 2nd International Conference on Broadband Networks},
  year = {2005},
  pages = {165--174},
  url = {http://dx.doi.org/10.1109/ICBN.2005.1589612},
  doi = {http://dx.doi.org/10.1109/ICBN.2005.1589612}
}
M. Li & Ramamurthy, B. (2005), "Survivable waveband switching in WDM mesh networks under dedicated path-protection", In GLOBECOM '05. IEEE Global Telecommunications Conference. Volume 4, pp. 1-5.
Abstract: This paper considers the problem of dedicated path-protection in wavelength-division multiplexed (WDM) mesh networks with waveband switching functionality under shared risk link group (SRLG) constraints. Two dedicated path-protection schemes are proposed, namely the PBABL scheme and the MPABWL scheme. The PBABL scheme protects each working waveband-path through a backup waveband-path. The MPABWL scheme protects each working waveband-path by either a backup waveband-path or multiple backup lightpaths. Heuristic algorithms adopting random optimization technique are proposed for both the schemes. The performance of the two protection schemes is studied and compared. Simulation results show that both the heuristics can obtain optimum solutions and the MPABWL scheme leads to less switching and transmission costs than the PBABL scheme.
BibTeX:
@inproceedings{LiRa05globecom,
  author = {M. Li and Ramamurthy, B.},
  title = {Survivable waveband switching in WDM mesh networks under dedicated path-protection},
  booktitle = {GLOBECOM '05. IEEE Global Telecommunications Conference},
  journal = {GLOBECOM '05. IEEE Global Telecommunications Conference},
  year = {2005},
  volume = {4},
  pages = {1--5},
  url = {http://dx.doi.org/10.1109/GLOCOM.2005.1577992},
  doi = {http://dx.doi.org/10.1109/GLOCOM.2005.1577992}
}
A. Todimala & Ramamurthy, B. (2005), "A heuristic with bounded guarantee to compute diverse paths under shared protection in WDM mesh network", In GLOBECOM '05. IEEE Global Telecommunications Conference. Volume 4, pp. 1915-1919.
Abstract: Establishing a fault-tolerant connection in a network involves computation of diverse working and protection paths. The shared risk link group (SRLG) (J. Strand et al. (2001) concept is used to model several types of failure conditions such as link, node, fiber conduit, etc. In this work we focus on the problem of computing optimal SRLG/link diverse paths under shared protection. Shared protection technique improves network resource utilization by allowing protection paths of multiple connections to share resources. In this work we propose an iterative heuristic for computing SRLG/link diverse paths. We present a method to calculate a quantitative measure that provides a bounded guarantee on the optimality of the diverse paths computed by the heuristic. The experimental results on computing link diverse paths show that our proposed heuristic is efficient in terms of number of iterations required (time taken) to compute diverse paths when compared to other previously proposed heuristics
BibTeX:
@inproceedings{ToRa05-gcom,
  author = {A. Todimala and Ramamurthy, B.},
  title = {A heuristic with bounded guarantee to compute diverse paths under shared protection in WDM mesh network},
  booktitle = {GLOBECOM '05. IEEE Global Telecommunications Conference},
  journal = {GLOBECOM '05. IEEE Global Telecommunications Conference},
  year = {2005},
  volume = {4},
  pages = {1915--1919},
  url = {http://dx.doi.org/10.1109/GLOCOM.2005.1578000},
  doi = {http://dx.doi.org/10.1109/GLOCOM.2005.1578000}
}
P. Adusumilli, X. Zou & Ramamurthy, B. (2005), "DGKD: Distributed group key distribution with authentication capability", In IAW '05. Information Assurance Workshop at the Sixth Annual IEEE Systems, Man and Cybernetics SMC Conference., pp. 286-293.
Abstract: Group key management (GKM) is the most important issue in secure group communication (SGC). The existing GKM protocols fall into three typical classes: centralized group key distribution (CGKD), decentralized group key management (DGKM), and distributed/contributory group key agreement (CGKA). Serious problems remains in these protocols, as they require existence of central trusted entities (such as group controller or subgroup controllers), relaying of messages (by subgroup controllers), or strict member synchronization (for multiple round stepwise key agreement), thus suffering from the single point of failure and attack, performance bottleneck, or misoperations in the situation of transmission delay or network failure. In this paper, we propose a new class of GKM protocols: distributed group key distribution (DGKD). The new DGKD protocol solves the above problems and surpasses the existing GKM protocols in terms of simplicity, efficiency, scalability, and robustness.
BibTeX:
@inproceedings{AdZR05iaw,
  author = {P. Adusumilli and X. Zou and Ramamurthy, B.},
  title = {DGKD: Distributed group key distribution with authentication capability},
  booktitle = {IAW '05. Information Assurance Workshop at the Sixth Annual IEEE Systems, Man and Cybernetics SMC Conference},
  journal = {IAW '05: Sixth Annual IEEE SMC Information Assurance Workshop},
  year = {2005},
  pages = {286--293},
  url = {http://dx.doi.org/10.1109/IAW.2005.1495965},
  doi = {http://dx.doi.org/10.1109/IAW.2005.1495965}
}
A. Todimala & Ramamurthy, B. (2005), "Least-cost disjoint paths with dependent cost structure in wavelength continuous optical WDM networks", In ICCCN 2005: 14th International Conference on Computer Communications and Networks., pp. 311-316.
Abstract: One of the important issues in establishing a fault tolerant connection in a wavelength division multiplexing optical network is computing a pair of disjoint working and protection paths and a free wavelength along the paths. While most of the earlier research focused only on computing disjoint paths, in this work we consider computing both disjoint paths and a free wavelength along the paths. The concept of dependent cost structure (DCS) of protection paths to enhance their resource sharing ability was proposed in our earlier work. In this work we extend the concept of DCS of protection paths to wavelength continuous networks. We formalize the problem of computing disjoint paths with DCS in wavelength continuous networks and prove that it is NP-complete. We present an iterative heuristic that uses a layered graph model to compute disjoint paths with DCS and identify a free wavelength.
BibTeX:
@inproceedings{ToRa05icccn,
  author = {A. Todimala and Ramamurthy, B.},
  title = {Least-cost disjoint paths with dependent cost structure in wavelength continuous optical WDM networks},
  booktitle = {ICCCN 2005: 14th International Conference on Computer Communications and Networks},
  journal = {ICCCN 2005: 14th International Conference on Computer Communications and Networks},
  year = {2005},
  pages = {311--316},
  url = {http://dx.doi.org/10.1109/ICCCN.2005.1523875},
  doi = {http://dx.doi.org/10.1109/ICCCN.2005.1523875}
}
R.K. Balachandran, Ramamurthy, B., X. Zou & Vinodchandran, N.V. (2005), "CRTDH: an efficient key agreement scheme for secure group communications in wireless ad hoc networks", In ICC 2005. IEEE International Conference on Communications. Volume 2, pp. 1123-1127.
Abstract: As a result of the growing popularity of wireless networks, in particular ad hoc networks, security over such networks has become very important. In this paper, we study the problem of secure group communications (SGC) and key management over ad hoc networks. We identify the key features of any SGC protocol for such networks. We also propose an efficient key agreement scheme for SGC. The scheme solves two important problems that exist in most current SGC schemes: requirement of member serialization and existence of a central entity. Besides this, the protocol also has many highly desirable properties such as contributory and efficient computation of group key, uniform work load for all the members, few rounds of rekeying (2 rounds for the initial key formation and join and 1 round for leave), and efficient support for high dynamics. These properties make the protocol well suited for wireless ad hoc networks.
BibTeX:
@inproceedings{BRZV05icc,
  author = {R.K. Balachandran and Ramamurthy, B. and X. Zou and Vinodchandran, N. V.},
  title = {CRTDH: an efficient key agreement scheme for secure group communications in wireless ad hoc networks},
  booktitle = {ICC 2005. IEEE International Conference on Communications},
  journal = {ICC 2005. IEEE International Conference on Communications},
  year = {2005},
  volume = {2},
  pages = {1123--1127},
  url = {http://dx.doi.org/10.1109/ICC.2005.1494522},
  doi = {http://dx.doi.org/10.1109/ICC.2005.1494522}
}
W. Yao, M. Li & Ramamurthy, B. (2005), "Performance analysis of sparse traffic grooming in WDM mesh networks", In ICC 2005. IEEE International Conference on Communications. Volume 3, pp. 1766-1770.
Abstract: Sparse traffic grooming is a practical problem to be addressed in heterogeneous multi-vendor optical WDM networks where only some of the optical cross-connects (OXCs) have grooming capabilities. Such a network is called as a sparse grooming network. The sparse grooming problem under dynamic traffic in optical WDM mesh networks is a relatively unexplored problem. In this work, we propose the maximize-lightpath-sharing multi-hop (MLS-MH) grooming algorithm to support dynamic traffic grooming in sparse grooming networks. We also present an analytical model to evaluate the blocking performance of the MLS-MH algorithm. Simulation results show that MLS-MH outperforms an existing grooming algorithm, the shortest-path single-hop (SPSH) algorithm. The numerical results from analysis show that it matches closely with the simulation. The effect of the number of grooming nodes in the network on the blocking performance is also analyzed.
BibTeX:
@inproceedings{YaLR05icc,
  author = {W. Yao and M. Li and Ramamurthy, B.},
  title = {Performance analysis of sparse traffic grooming in WDM mesh networks},
  booktitle = {ICC 2005. IEEE International Conference on Communications},
  journal = {ICC 2005. IEEE International Conference on Communications},
  year = {2005},
  volume = {3},
  pages = {1766--1770},
  url = {http://dx.doi.org/10.1109/ICC.2005.1494645},
  doi = {http://dx.doi.org/10.1109/ICC.2005.1494645}
}
W. Yao & Ramamurthy, B. (2005), "Survivable traffic grooming with path protection at the connection level in WDM mesh networks", IEEE/OSA Journal of Lightwave Technology., In IEEE/OSA Journal of Lightwave Technology. Vol. 23(10), pp. 2846-2853.
Abstract: Survivable traffic grooming (STG) is a promising approach to provide reliable and resource-efficient multigranularity connection services in wavelength-division-multiplexing (WDM) optical networks. In this paper, we study the STG problem in WDM mesh optical networks employing path protection at the connection level. Both dedicated-protection and shared-protection schemes are considered. Given network resources, the objective of the STG problem is to maximize network throughput. To enable survivability under various kinds of single failures, such as fiber cut and duct cut, we consider the general shared-risk-link-group (SRLG) diverse routing constraints. We first resort to the integer-linear-programming (ILP) approach to obtain optimal solutions. To address its high computational complexity, we then propose three efficient heuristics, namely separated survivable grooming algorithm (SSGA), integrated survivable grooming algorithm (ISGA), and tabu-search survivable grooming algorithm (TSGA). While SSGA and ISGA correspond to an overlay network model and a peer network model, respectively, TSGA further improves the grooming results from SSGA and ISGA by incorporating the effective tabu-search (TS) method. Numerical results show that the heuristics achieve comparable solutions to the ILP approach, which uses significantly longer running times than the heuristics.
BibTeX:
@article{YaRa05jlt-Survivable,
  author = {W. Yao and Ramamurthy, B.},
  title = {Survivable traffic grooming with path protection at the connection level in WDM mesh networks},
  booktitle = {IEEE/OSA Journal of Lightwave Technology},
  journal = {IEEE/OSA Journal of Lightwave Technology},
  year = {2005},
  volume = {23},
  number = {10},
  pages = {2846--2853},
  url = {http://dx.doi.org/10.1109/JLT.2005.856269},
  doi = {http://dx.doi.org/10.1109/JLT.2005.856269}
}
S. Anumalla, Ramamurthy, B., Gosselin, D.C. & Burbach, M. (2005), "Groundwater monitoring using smart sensors", In IEEE International Conference on Electro Information Technology., pp. 1-6.
Abstract: Groundwater resources are the principal source of drinking water for about 50 percent of the United States population. Groundwater resources in Nebraska are under increasing stress as there is a rapid growth in their usage. Water managers need more timely and accurate data to assess ground-water conditions to manage adverse situations such as drought and loss of pumpage in agriculture and domestic water supply. Currently groundwater researchers use stand-alone data logging equipment which is labor intensive and the method is not easily scalable if the number of logging locations increases. Commercially available real-time data monitoring solutions are either prohibitively costly or highly inflexible. In this paper, we present a design for a groundwater monitoring system based on a network of wirelessly-linked pressure sensors. The proposed solution will enable groundwater researchers and decision makers to have quick access to the groundwater data with less effort and cost. Though our design is initially meant for groundwater monitoring, it can be easily adapted to other fields of environmental monitoring.
BibTeX:
@inproceedings{ARGB05eit,
  author = {S. Anumalla and Ramamurthy, B. and Gosselin, D. C. and Burbach, M.},
  title = {Groundwater monitoring using smart sensors},
  booktitle = {IEEE International Conference on Electro Information Technology},
  journal = {EIT 2005. IEEE International Conference on Electro Information Technology},
  year = {2005},
  pages = {1--6},
  url = {http://dx.doi.org/10.1109/EIT.2005.1626962},
  doi = {http://dx.doi.org/10.1109/EIT.2005.1626962}
}
B. Lekkala & Ramamurthy, B. (2005), "Discontinuous waveband switching in WDM optical networks", In IEEE International Conference on Electro Information Technology (EIT)., pp. 1-5.
Abstract: Routing techniques used in wavelength routed optical networks (WRN) do not give an efficient solution with waveband routed optical networks (WBN) as the objective of routing in WRN is to reduce the blocking probability and that in WBN is to reduce the number of switching ports. Routing in WBN can be divided two parts, finding the route and grouping the wavelength assigned into that route with some existing wavelengths/wavebands. In this paper, we propose a heuristic for waveband routing, which uses a new grouping strategy called discontinuous waveband grouping to group the wavelengths into a waveband. The main objective of our algorithm is to decrease the total number of ports required and reduce the blocking probability of the network. The performance of the heuristic is analyzed using simulation on a WBN with non-uniform wavebands.
BibTeX:
@inproceedings{LeRa05eit,
  author = {B. Lekkala and Ramamurthy, B.},
  title = {Discontinuous waveband switching in WDM optical networks},
  booktitle = {IEEE International Conference on Electro Information Technology (EIT)},
  journal = {EIT 2005: IEEE International Conference on Electro Information Technology},
  year = {2005},
  pages = {1--5},
  url = {http://dx.doi.org/10.1109/EIT.2005.1626979},
  doi = {http://dx.doi.org/10.1109/EIT.2005.1626979}
}
W. Yao & Ramamurthy, B. (2005), "A Link Bundled Auxiliary Graph Model for Constrained Dynamic Traffic Grooming in WDM Mesh Networks", IEEE Journal on Selected Areas in Communications., In IEEE Journal on Selected Areas in Communications (JSAC). Vol. 23(8), pp. 1542-1555.
Abstract: This paper addresses the two-layer dynamic traffic grooming problem in wavelength-division-multiplexed (WDM) mesh optical networks subject to resource constraints and the generalized wavelength continuity (GWC) constraint. The GWC constraint is a relaxed wavelength continuity constraint which incorporates various kinds of wavelength conversion capabilities that exist in optical networks. As an improvement over the existing layered auxiliary graph (layered-AG) approach which represents each wavelength separately in the auxiliary graph, we introduce a largely simplified link bundled auxiliary graph (LBAG) model and propose the SAG-LB method to find paths and assign wavelengths for new lightpaths subject to the GWC constraint. We propose the constrained integrated grooming algorithm (CIGA) based on the LBAG model. A grooming policy influences the resource utilization by determining the weight function of the auxiliary graph. We propose the least resource path first (LR) grooming policy, which is an improvement over the existing grooming policies in the literature, by integrating the wavelength and transceiver metrics together. Simulation results show that the LBAG model achieves a comparable blocking performance with the layered-AG approach while using a significantly less amount of running time. We also present the worst case time complexity analysis of the CIGA grooming algorithm and evaluate the performance of the LR grooming policy by simulation.
BibTeX:
@article{YaRa05jsac,
  author = {W. Yao and Ramamurthy, B.},
  title = {A Link Bundled Auxiliary Graph Model for Constrained Dynamic Traffic Grooming in WDM Mesh Networks},
  booktitle = {IEEE Journal on Selected Areas in Communications (JSAC)},
  journal = {IEEE Journal on Selected Areas in Communications},
  year = {2005},
  volume = {23},
  number = {8},
  pages = {1542--1555},
  url = {http://dx.doi.org/10.1109/JSAC.2005.851792},
  doi = {http://dx.doi.org/10.1109/JSAC.2005.851792}
}
L. Shen, X. Yang & Ramamurthy, B. (2005), "Shared Risk Link Group (SRLG)-Diverse Path Provisioning Under Hybrid Service Level Agreements in Wavelength-Routed Optical Mesh Networks", IEEE/ACM Transactions on Networking., In IEEE/ACM Transactions on Networking. Vol. 13(4), pp. 918-931.
Abstract: The static provisioning problem in wavelength-routed optical networks has been studied for many years. However, service providers are still facing the challenges arising from the special requirements for provisioning services at the optical layer. In this paper, we incorporate some realistic constraints into the static provisioning problem, and formulate it under different network resource availability conditions. We consider three classes of shared risk link group (SRLG)-diverse path protection schemes: dedicated, shared, and unprotected. We associate with each connection request a lightpath length constraint and a revenue value. When the network resources are not sufficient to accommodate all the connection requests, the static provisioning problem is formulated as a revenue maximization problem, whose objective is maximizing the total revenue value. When the network has sufficient resources, the problem becomes a capacity minimization problem with the objective of minimizing the number of used wavelength-links. We provide integer linear programming (ILP) formulations for these problems. Because solving these ILP problems is extremely time consuming, we propose a tabu search heuristic to solve these problems within a reasonable amount of time. We also develop a rerouting optimization heuristic, which is based on previous work. Experimental results are presented to compare the solutions obtained by the tabu search heuristic and the rerouting optimization heuristic. For both problems, the tabu search heuristic outperforms the rerouting optimization heuristic.
BibTeX:
@article{ShYR05ton,
  author = {L. Shen and X. Yang and Ramamurthy, B.},
  title = {Shared Risk Link Group (SRLG)-Diverse Path Provisioning Under Hybrid Service Level Agreements in Wavelength-Routed Optical Mesh Networks},
  booktitle = {IEEE/ACM Transactions on Networking},
  journal = {IEEE/ACM Transactions on Networking},
  year = {2005},
  volume = {13},
  number = {4},
  pages = {918--931},
  url = {http://dx.doi.org/10.1109/TNET.2005.852879},
  doi = {http://dx.doi.org/10.1109/TNET.2005.852879}
}
M. Li & Ramamurthy, B. (2005), "Dynamic Waveband Switching in WDM Mesh Networks Based on a Generic Auxiliary Graph Model", Photonic Network Communications., November, 2005. Vol. 10(3), pp. 309-331.
Abstract: Waveband switching (WBS) is a promising technique to reduce the switching and transmission costs in the optical domain of a wavelength-division multiplexing (WDM) network. This paper considers the problem of provisioning dynamic traffic using WBS in a WDM mesh network. The network of interest is a homogeneous WBS network, where each node has the functionality of WBS. The problem is called the dynamic WBS problem, which involves searching waveband-routes or wavelength-routes for the dynamically arriving traffic requests. The objective is to minimize the total switching and transmission costs in the optical domain. To solve the dynamic WBS problem, an auxiliary graph model capturing the network state is proposed. Based on the auxiliary graph, two heuristic on-line WBS algorithms with different waveband grouping policies are proposed, namely the wavelength-first WBS algorithm based on the auxiliary graph (WFAUG) and the waveband-first WBS algorithm based on the auxiliary graph (BFAUG). Simulation results indicate that WBS is an attractive technique which reduces the overall switching and transmission costs by up to 30% in the network. The results also show that the WFAUG algorithm outperforms the BFAUG algorithm in terms of port savings and cost savings.
BibTeX:
@article{Li2005Dynamic,
  author = {M. Li and Ramamurthy, Byrav},
  title = {Dynamic Waveband Switching in WDM Mesh Networks Based on a Generic Auxiliary Graph Model},
  journal = {Photonic Network Communications},
  year = {2005},
  volume = {10},
  number = {3},
  pages = {309--331},
  url = {http://www.citeulike.org/pdf/user/byrav/article/3006815/li_05_dynamic.pdf},
  doi = {http://dx.doi.org/10.1007/s11107-005-3493-x}
}
X. Yang & Ramamurthy, B. (2005), "Sparse Regeneration in Translucent Wavelength-Routed Optical Networks: Architecture, Network Design and Wavelength Routing", Photonic Network Communications., July, 2005. Vol. 10(1), pp. 39-53.
Abstract: In this paper we study an alternate network architecture, called translucent network, to the fully transparent and fully opaque network architectures. In a translucent wavelength-routed optical network, a technique called sparse regeneration is used to overcome the severe lightpath blocking due to signal quality degradation and wavelength contention in a fully transparent network while using much less regenerators than in a fully opaque network. In this paper, we present a node model and a network model that perform sparse regeneration. We address the problem of translucent network design by proposing several regenerator placement algorithms based on different knowledge of future network traffic patterns. We also address the problem of wavelength routing under sparse regeneration by incorporating two regenerator allocation strategies with heuristic wavelength routing algorithms. We compare the performance of different regenerator placement algorithms and wavelength routing schemes through simulation experiments. The benefit of sparse regeneration is quantitatively measured under different network settings.
BibTeX:
@article{Yang2005Sparse,
  author = {X. Yang and Ramamurthy, Byrav},
  title = {Sparse Regeneration in Translucent Wavelength-Routed Optical Networks: Architecture, Network Design and Wavelength Routing},
  journal = {Photonic Network Communications},
  year = {2005},
  volume = {10},
  number = {1},
  pages = {39--53},
  url = {http://dx.doi.org/10.1007/s11107-005-1694-y},
  doi = {http://dx.doi.org/10.1007/s11107-005-1694-y}
}
N. Mohamed, X. Liu, A. Davis & Ramamurthy, B. (2005), "JOR: a content-based object router", Computer Communications., In On Activated and Programmable Internet: Converging Technologies for Internet-based Active and Programmable Systems., April, 2005. Vol. 28(6), pp. 654-663.
Abstract: Content-based routing has emerged as a new routing paradigm, allowing messages to be routed based on defined fields within the message. Content-based routers generally employ XML, which has two main disadvantages. First, each message is translated into XML when sent, and translated out of XML when received. Second, XML limits the objects sent to three types--data, documents, and messages. We introduce here an extensible content-based object router that goes beyond messages to routing entire Java objects. The Java Object Router (JOR) is an application-level router that allows Java objects to be routed according to their IP address, their label, their object type, or any of their content. In addition, JOR provides mechanisms to deal with varying routing policies. JOR separates routing mechanisms from routing policies, making it adaptable and easy to use in a variety of applications. To illustrate the advantages and performance of JOR, a prototype was implemented to experimentally evaluate the content-based object routing mechanisms.
BibTeX:
@article{MLDR04ccom,
  author = {N. Mohamed and X. Liu and A. Davis and Ramamurthy, Byrav},
  title = {JOR: a content-based object router},
  booktitle = {On Activated and Programmable Internet: Converging Technologies for Internet-based Active and Programmable Systems},
  journal = {Computer Communications},
  year = {2005},
  volume = {28},
  number = {6},
  pages = {654--663},
  url = {http://dx.doi.org/10.1016/j.comcom.2004.08.008},
  doi = {http://dx.doi.org/10.1016/j.comcom.2004.08.008}
}
X. Yang, L. Shen & Ramamurthy, B. (2005), "Survivable Lightpath Provisioning in WDM Mesh Networks Under Shared Path Protection and Signal Quality Constraints", IEEE/OSA Journal of Lightwave Technology., April, 2005. Vol. 23(4), pp. 1556-1567. OSA.
Abstract: This paper addresses the problem of survivable lightpath provisioning in wavelength-division-multiplexing (WDM) mesh networks, taking into consideration optical-layer protection and some realistic optical signal quality constraints. The investigated networks use sparsely placed optical-electrical-optical (O/E/O) modules for regeneration and wavelength conversion. Given a fixed network topology with a number of sparsely placed O/E/O modules and a set of connection requests, a pair of link-disjoint lightpaths is established for each connection. Due to physical impairments and wavelength continuity,both the working and protection lightpaths need to be regenerated at some intermediate nodes to overcome signal quality degradation and wavelength contention. In the present paper, resource-efficient provisioning solutions are achieved with the objective of maximizing resource sharing. The authors propose a resource-sharing scheme that supports three kinds of resource-sharing scenarios, including a conventional wavelength-link sharing scenario, which shares wavelength links between protection lightpaths, and two new scenarios, which share O/E/O modules between protection lightpaths and between working and protection lightpaths. An integer linear programming (ILP)-based solution approach is used to find optimal solutions. The authors also propose a local optimization heuristic approach and a tabu search heuristic approach to solve this problem for real-world,large mesh networks. Numerical results show that our solution approaches work well under a variety of network settings and achieves a high level of resource-sharing rates (over 60% for O/E/O modules and over 30% for wavelength links), which translate into great savings in network costs.
BibTeX:
@article{YaSR05jlt,
  author = {X. Yang and L. Shen and Ramamurthy, Byrav},
  title = {Survivable Lightpath Provisioning in WDM Mesh Networks Under Shared Path Protection and Signal Quality Constraints},
  journal = {IEEE/OSA Journal of Lightwave Technology},
  publisher = {OSA},
  year = {2005},
  volume = {23},
  number = {4},
  pages = {1556--1567},
  url = {http://dx.doi.org/10.1109/JLT.2005.844495},
  doi = {http://dx.doi.org/10.1109/JLT.2005.844495}
}
W. Yao, M. Li & Ramamurthy, B. (2005), "Design of Sparse Grooming Networks for Transporting Dynamic Multi-Granularity Sub-Wavelength Traffic", In Optical Fiber Communication Conference and Exposition and The National Fiber Optic Engineers Conference. March 2005., pp. 1-3. Optical Society of America.
Abstract: A sparse grooming network (SGN) is a cost-effective solution to provision multi-granularity sub-wavelength connections with stringent budget constraints. We address the design of SGNs by proposing efficient sparse grooming algorithms and G-node placement heuristics.
BibTeX:
@inproceedings{YaLR05ofc,
  author = {W. Yao and M. Li and Ramamurthy, Byrav},
  title = {Design of Sparse Grooming Networks for Transporting Dynamic Multi-Granularity Sub-Wavelength Traffic},
  booktitle = {Optical Fiber Communication Conference and Exposition and The National Fiber Optic Engineers Conference},
  publisher = {Optical Society of America},
  year = {2005},
  pages = {1--3},
  url = {http://www.opticsinfobase.org/abstract.cfm?id=109791}
}
X. Yang & Ramamurthy, B. (2005), "Dynamic Routing in Translucent WDM Optical Networks: The Intradomain Case", IEEE/OSA Journal of Lightwave Technology., March, 2005. Vol. 23(3), pp. 955-957. OSA.
Abstract: Translucent wavelength-division multiplexing optical networks use sparse placement of regenerators to overcome physical impairments and wavelength contention introduced by fully transparent networks, and achieve a performance close to fully opaque networks at a much less cost. In previous studies, we addressed the placement of regenerators based on static schemes,allowing for only a limited number of regenerators at fixed locations. This paper furthers those studies by proposing a dynamic resource allocation and dynamic routing scheme to operate translucent networks. This scheme is realized through dynamically sharing regeneration resources, including transmitters,receivers, and electronic interfaces, between regeneration and access functions under a multidomain hierarchical translucent network model. An intradomain routing algorithm, which takes into consideration optical-layer constraints as well as dynamic allocation of regeneration resources, is developed to address the problem of translucent dynamic routing in a single routing domain. Network performance in terms of blocking probability, resource utilization, and running times under different resource allocation and routing schemes is measured through simulation experiments.
BibTeX:
@article{YaRa05jlt-Dynamic,
  author = {X. Yang and Ramamurthy, Byrav},
  title = {Dynamic Routing in Translucent WDM Optical Networks: The Intradomain Case},
  journal = {IEEE/OSA Journal of Lightwave Technology},
  publisher = {OSA},
  year = {2005},
  volume = {23},
  number = {3},
  pages = {955--957},
  url = {http://dx.doi.org/10.1109/JLT.2004.841446},
  doi = {http://dx.doi.org/10.1109/JLT.2004.841446}
}
L. Shen, X. Yang & Ramamurthy, B. (2004), "A load-balancing spare capacity reallocation approach in service-rich SONET metro mesh networks", In Broadnets 2004: First International Conference on Broadband Networks., pp. 269-278.
Abstract: The next-generation SONET metro network is evolving into a service-rich infrastructure. At the edge of such a network, multi-service provisioning platforms (MSPPs) provide efficient data mapping enabled by generic framing procedure (GFP) and virtual concatenation (VC). The core of the network tends to be a meshed architecture equipped with multi-service switches (MSSs), In the context of these emerging technologies, we propose a load-balancing spare capacity reallocation approach to improve network utilization in the next-generation SONET metro networks. Using our approach, carriers can postpone network upgrades, resulting in increased revenue with reduced capital expenditures (CAPEX). For the first time, we consider the spare capacity reallocation problem from a capacity upgrade and network planning perspective. Our approach can operate in the context of shared-path protection (with backup multiplexing) because it reallocates spare capacity without disrupting working services. Unlike previous spare capacity reallocation approaches which aim at minimizing total spare capacity, our load-balancing approach minimizes the network load vector (NLV), which is a novel metric that reflects the network load distribution. Because NLV takes into consideration both uniform and non-uniform link capacity distribution, our approach can benefit both uniform and non-uniform networks. We develop a greedy load-balancing spare capacity reallocation (GLB-SCR) heuristic algorithm to implement this approach. Our experimental results show that GLB-SCR outperforms a previously proposed algorithm (SSR) in terms of established connection capacity and total network capacity in both uniform and non-uniform networks.
BibTeX:
@inproceedings{ShYR04broadnets,
  author = {L. Shen and X. Yang and Ramamurthy, B.},
  title = {A load-balancing spare capacity reallocation approach in service-rich SONET metro mesh networks},
  booktitle = {Broadnets 2004: First International Conference on Broadband Networks},
  journal = {Broadnets 2004. First International Conference on Broadband Networks},
  year = {2004},
  pages = {269--278},
  url = {http://dx.doi.org/10.1109/BROADNETS.2004.6},
  doi = {http://dx.doi.org/10.1109/BROADNETS.2004.6}
}
A. Todimala & Ramamurthy, B. (2004), "Survivable virtual topology routing under shared risk link groups in WDM networks", In Broadnets 2004: First International Conference on Broadband Networks., pp. 130-139.
Abstract: Network survivability is one of the most important issues in the design of optical WDM networks. In this work we study the problem of survivable routing of a virtual topology on a physical topology with shared risk link groups (SRLG). The survivable virtual topology routing problem against single-link failures in the physical topology is proved to be NP-complete in E. Modiano and A. Narula-Tam, May 2002. We prove that survivable virtual topology routing problem against SRLG/node failures is also NP-complete. We present an improved integer linear programming (ILP) formulation (in comparison to E. Modiano and A. Narula-Tam, May 2002) for computing the survivable routing under SRLG/node failures. Using an ILP solver, we computed the survivable virtual topology routing against link and SRLG failures for small and medium sized networks efficiently. As even our improved ILP formulation becomes intractable for large networks, we present a congestion-based heuristic and a tabu search heuristic (which uses the congestion-based heuristic solution as the initial solution) for computing survivable routing of a virtual topology. Our experimental results show that tabu search heuristic coupled with the congestion based heuristic (used as initial solution) provides fast and near-optimal solutions.
BibTeX:
@inproceedings{ToRa04broadnets,
  author = {A. Todimala and Ramamurthy, B.},
  title = {Survivable virtual topology routing under shared risk link groups in WDM networks},
  booktitle = {Broadnets 2004: First International Conference on Broadband Networks},
  journal = {Broadnets 2004. First International Conference on Broadband Networks},
  year = {2004},
  pages = {130--139},
  url = {http://dx.doi.org/10.1109/BROADNETS.2004.81},
  doi = {http://dx.doi.org/10.1109/BROADNETS.2004.81}
}
W. Yao & Ramamurthy, B. (2004), "Survivable traffic grooming with path protection at the connection level in WDM mesh networks", In Broadnets 2004: First International Conference on Broadband Networks., pp. 310-319.
Abstract: Survivable traffic grooming (STG) is a promising approach to provide reliable and resource-efficient multigranularity connection services in wavelength division multiplexing (WDM) optical networks. In this paper, we study the STG problem in WDM mesh optical networks employing path protection at the connection level. Both dedicated protection and shared protection schemes are considered. Given the network resources, the objective of the STG problem is to maximize network throughput. To enable survivability under various kinds of single failures such as fiber cut and duct cut, we consider the general shared risk link group (SRLG) diverse routing constraints. We first resort to the integer linear programming (ILP) approach to obtain optimal solutions. To address its high computational complexity, we then propose three efficient heuristics, namely separated survivable grooming algorithm (SSGA), integrated survivable grooming algorithm (ISGA) and tabu search survivable grooming algorithm (TSGA). While SSGA and ISGA correspond to an overlay network model and a peer network model respectively, TSGA further improves the grooming results from SSGA and ISGA by incorporating the effective tabu search method. Numerical results show that the heuristics achieve comparable solutions to the ILP approach, which uses significantly longer running times than the heuristics.
BibTeX:
@inproceedings{YaRa04broadnets,
  author = {W. Yao and Ramamurthy, B.},
  title = {Survivable traffic grooming with path protection at the connection level in WDM mesh networks},
  booktitle = {Broadnets 2004: First International Conference on Broadband Networks},
  journal = {Broadnets 2004. First International Conference on Broadband Networks},
  year = {2004},
  pages = {310--319},
  url = {http://dx.doi.org/10.1109/BROADNETS.2004.80},
  doi = {http://dx.doi.org/10.1109/BROADNETS.2004.80}
}
W. Yao & Ramamurthy, B. (2004), "Rerouting schemes for dynamic traffic grooming in optical WDM mesh networks", In GLOBECOM '04: IEEE Global Telecommunications Conference. Volume 3, pp. 1793-1797.
Abstract: Traffic grooming in optical WDM mesh networks is a two-layer routing problem to pack low-rate connections effectively onto high-rate lightpaths, which, in turn, are established on wavelength links. We employ the rerouting approach to improve the network throughput under the dynamic traffic model. We propose two rerouting schemes, rerouting at lightpath level (RRAL) and rerouting at connection level (RRAC). A qualitative comparison is made between RRAL and RRAC. We also propose the critical-wavelength-avoiding one-lightpath-limited (CWA-1L) and critical-lightpath-avoiding one-connection-limited (CLA-1C) rerouting heuristics, which are based on the respective rerouting schemes. Simulation results show that rerouting reduces the connection blocking probability significantly.
BibTeX:
@inproceedings{YaRa04globecom,
  author = {W. Yao and Ramamurthy, B.},
  title = {Rerouting schemes for dynamic traffic grooming in optical WDM mesh networks},
  booktitle = {GLOBECOM '04: IEEE Global Telecommunications Conference},
  journal = {GLOBECOM '04. IEEE Global Telecommunications Conference},
  year = {2004},
  volume = {3},
  pages = {1793--1797},
  url = {http://dx.doi.org/10.1109/GLOCOM.2004.1378291},
  doi = {http://dx.doi.org/10.1109/GLOCOM.2004.1378291}
}
M. Li & Ramamurthy, B. (2004), "A graph model for dynamic waveband switching in WDM mesh networks", In ICC 2004. IEEE International Conference on Communications. Volume 3, pp. 1821-1825.
Abstract: The problem of waveband switching (WBS) in a wavelength-division multiplexing (WDM) mesh network with dynamic traffic requests is investigated. To solve the WBS problem in a homogeneous dynamic WBS network, where every node is a multigranular optical crossconnect (MG-OXC), we construct an auxiliary graph. Based on the auxiliary graph, we develop two heuristic on-line WBS algorithms with different grouping policies, namely the wavelength-first WBS algorithm based on the auxiliary graph (WFAUG) and the waveband-first WBS algorithm based on the auxiliary graph (BFAUG). Our results show that the WFAUG algorithm outperforms the BFAUG algorithm.
BibTeX:
@inproceedings{LiRa04icc,
  author = {M. Li and Ramamurthy, B.},
  title = {A graph model for dynamic waveband switching in WDM mesh networks},
  booktitle = {ICC 2004. IEEE International Conference on Communications},
  journal = {ICC 2004, IEEE International Conference on Communications},
  year = {2004},
  volume = {3},
  pages = {1821--1825},
  url = {http://dx.doi.org/10.1109/ICC.2004.1312822},
  doi = {http://dx.doi.org/10.1109/ICC.2004.1312822}
}
W. Yao & Ramamurthy, B. (2004), "Survivable traffic grooming with differentiated end-to-end availability guarantees in WDM mesh networks", In LANMAN 2004. The 13th IEEE Workshop on Local and Metropolitan Area Networks., pp. 87-90.
Abstract: Traffic grooming is critical in WDM optical metropolitan area networks (MANs), where low-rate connections are packed onto high-rate wavelength paths (lightpaths). Various applications in the MAN demand different levels of reliability. Therefore, it is necessary to provision connections with differentiated reliability guarantees in the MAN. In this paper, we first present an analytical model to calculate the availability of connections using different protection schemes in WDM optical MANs with general mesh topologies. Then we propose and simulate two grooming algorithms which can provision availability guaranteed connections based on per-connection requirements.
BibTeX:
@inproceedings{YaRa04lanman,
  author = {W. Yao and Ramamurthy, B.},
  title = {Survivable traffic grooming with differentiated end-to-end availability guarantees in WDM mesh networks},
  booktitle = {LANMAN 2004. The 13th IEEE Workshop on Local and Metropolitan Area Networks},
  journal = {LANMAN 2004. The 13th IEEE Workshop on Local and Metropolitan Area Networks},
  year = {2004},
  pages = {87--90},
  url = {http://dx.doi.org/10.1109/LANMAN.2004.1338407},
  doi = {http://dx.doi.org/10.1109/LANMAN.2004.1338407}
}
V. Kasarekar & Ramamurthy, B. (2004), "Distributed hybrid agent based intrusion detection and real time response system", In Broadnets 2004: First International Conference on Broadband Networks., pp. 739-741.
Abstract: Wireless LANs are growing rapidly and security has always been a concern. We have implemented a hybrid system, which does not only detect active attacks such as identity theft causing denial of service attacks, but also detects the usage of accesspoint discovery tools. The system responds in real time by sending out an alert to the network administrator.
BibTeX:
@inproceedings{KaRa04broadnets,
  author = {V. Kasarekar and Ramamurthy, B.},
  title = {Distributed hybrid agent based intrusion detection and real time response system},
  booktitle = {Broadnets 2004: First International Conference on Broadband Networks},
  journal = {Broadnets 2004. First International Conference on Broadband Networks},
  year = {2004},
  pages = {739--741},
  url = {http://dx.doi.org/10.1109/BROADNETS.2004.33},
  doi = {http://dx.doi.org/10.1109/BROADNETS.2004.33}
}
A. Todimala & Ramamurthy, B. (2004), "IMSH: an iterative heuristic for SRLG diverse routing in WDM mesh networks", In ICCCN 2004: 13th International Conference on Computer Communications and Networks., pp. 199-204.
Abstract: Survivable routing of a connection involves computation of a pair of diverse routes such that at most one route fails when failures occur in the network topology. A subset of links in the network that share the risk of failure at the same time are said to belong to a shared risk link group (SRLG) [J. Strand et al., Feb 2001]. A network with shared risk link groups defined over its links is an SRLG network. A failure of an SRLG is equivalent to the failure of all the links in the SRLG. For a connection to be survivable in an SRLG network, its working and protection paths must be routed on SRLG diverse paths. SRLG diverse routing problem has been proved to be NP-complete in J.Q. Hu (2003). According to the quality of service requirement of a survivable connection request, dedicated protection or shared protection can be used to establish the connection request. With dedicated protection, the connection is established on both the SRLG diverse working and protection paths. The simplest heuristic for computing SRLG diverse path pair is the two-step approach, but it suffers from the trap topology problem. In the previous study by Pin-Han Ho, an iterative heuristic (ITSH) using the two-step approach was proposed to compute the least cost SRLG diverse path pair. Suurballe's algorithm computes a pair of least cost link-disjoint paths between a node pair. In this work, we present a modified Suurballe's heuristic for computing the SRLG diverse routes between a node pair. We then propose an iterative heuristic (IMSH) which uses the modified Suurballe's heuristic for computing the least cost SRLG diverse routes. We also present an 1/2-cost-improvement optimality check criterion for dedicated protection
BibTeX:
@inproceedings{ToRa04icccn,
  author = {A. Todimala and Ramamurthy, B.},
  title = {IMSH: an iterative heuristic for SRLG diverse routing in WDM mesh networks},
  booktitle = {ICCCN 2004: 13th International Conference on Computer Communications and Networks},
  journal = {ICCCN 2004: 13th International Conference on Computer Communications and Networks},
  year = {2004},
  pages = {199--204},
  url = {http://dx.doi.org/10.1109/ICCCN.2004.1401627},
  doi = {http://dx.doi.org/10.1109/ICCCN.2004.1401627}
}
X. Zou, Ramamurthy, B. & Magliveras, S.S. (2004), "A GCD attack resistant CRTHACS for secure group communications", In ITCC 2004. International Conference on Information Technology: Coding and Computing. Volume 2, pp. 153-154.
Abstract: We propose an improved CRTHACS scheme for secure group communications. The scheme resists several GCD attacks which exist in the original CRTHACS scheme [X. Zou et al., (2001)] and were reported in [R. Steinwandt et al., (2003)].
BibTeX:
@inproceedings{ZoRM04itcc,
  author = {X. Zou and Ramamurthy, B. and Magliveras, S. S.},
  title = {A GCD attack resistant CRTHACS for secure group communications},
  booktitle = {ITCC 2004. International Conference on Information Technology: Coding and Computing},
  journal = {ITCC 2004. International Conference on Information Technology: Coding and Computing},
  year = {2004},
  volume = {2},
  pages = {153--154},
  url = {http://dx.doi.org/10.1109/ITCC.2004.1286618},
  doi = {http://dx.doi.org/10.1109/ITCC.2004.1286618}
}
S. Sunkavalli & Ramamurthy, B. (2004), "MTSF: A Fast Mesh Scatternet Formation Algorithm for Bluetooth Networks", In GLOBECOM '04. IEEE Global Telecommunications Conference. Dallas, TX. November/December 2004. Volume 6, pp. 3594-3598.
Abstract: Bluetooth is a short range technology that enables the formation of wireless personal area networks (WPAN). Although a Bluetooth node can form a network, called a piconet, with other nodes within its radio range, the technology can be better exploited if multiple piconets can be interconnected to form a large overlay network called a scatternet.We propose a Mesh Topology Scatternet Formation (MTSF) algorithm, for Bluetooth networks. The algorithm has short delays for new node acceptance and scatternet formation while localizing the impact of node additions and deletions. Using extensive simulations based on the ns-2 simulator we demonstrate that MTSF is well suited for scatternet formation over a large area as it is distributed and scalable both in terms of the number of nodes and in the area spanned by the scatternet.
BibTeX:
@inproceedings{SuRa04,
  author = {S. Sunkavalli and Ramamurthy, B.},
  title = {MTSF: A Fast Mesh Scatternet Formation Algorithm for Bluetooth Networks},
  booktitle = {GLOBECOM '04. IEEE Global Telecommunications Conference},
  journal = {GLOBECOM'04. IEEE Global Communications Conference},
  year = {2004},
  volume = {6},
  pages = {3594--3598}
}
X. Zou, Magliveras, S. & Ramamurthy, B. (2004), "Key Tree based Scalable Secure Dynamic Conferencing Schemes", International Conference on Parallel and Distributed Computing and Systems (PDCS 2004)., November, 2004. , pp. 61-65.
Abstract: In this paper, we propose two conference key management schemes for secure dynamic conferencing: one is a centralized scheme and the other a distributed one. Both schemes are based on a (key) tree structure so they are scalable and efficient. Moreover, both schemes allow highly group dynamics.
BibTeX:
@article{zmr:2004:ktssdcs--NSTD,
  author = {X. Zou and S. Magliveras and B. Ramamurthy},
  title = {Key Tree based Scalable Secure Dynamic Conferencing Schemes},
  journal = {International Conference on Parallel and Distributed Computing and Systems (PDCS 2004)},
  year = {2004},
  pages = {61--65},
  url = {http://www.actapress.com/PaperInfo.aspx?PaperID=17832&reason=500}
}
W. Yao & Ramamurthy, B. (2004), "Dynamic Traffic Grooming using Fixed-Alternate Routing in WDM Mesh Optical Networks", In First Workshop on Traffic Grooming in WDM Networks, Co-located with Broadnets 2004. October 2004.
Abstract: There is a mismatch between lightpath channel capacity and traffic request capacity in wavelength division multiplexed (WDM) optical mesh networks. Traffic grooming is needed to resolve this mismatch in an efficient way. We study the dynamic traffic grooming problem in WDM mesh networks using the fixed-alternate routing (FAR) approach. Based on the FAR approach, we propose the fixed-order grooming (FOG) algorithm to support on-line provisioning of multi-granularity sub-wavelength connections. As traffic grooming involves two-layered routing, it is significantly different from the routing and wavelength assignment (RWA) problem in wavelength-routed WDM networks. We introduce the route selection problem (also called grooming node selection problem) and propose three grooming policies to address this problem. The three grooming policies are load sharing (LS), sequential grooming (SG) and minimum gap (MG). To address the wavelength and transceiver constraints, we propose another three grooming policies including least physical hop first (LPH), least virtual hop first (LVH) and least stringent resource first (LSR). Simulations are conducted to evaluate the performance of the FOG grooming algorithm and the grooming policies.
BibTeX:
@inproceedings{YaRa04d--NSTD,
  author = {W. Yao and Ramamurthy, B.},
  title = {Dynamic Traffic Grooming using Fixed-Alternate Routing in WDM Mesh Optical Networks},
  booktitle = {First Workshop on Traffic Grooming in WDM Networks, Co-located with Broadnets 2004},
  year = {2004},
  url = {http://netlab.unl.edu/netgroup/pubs/FixAltGrooming-wtg2004.pdf}
}
X. Zou, Ramamurthy, B. & Magliveras, S.S. (2004), "Secure Group Communications Over Data Networks", Hardcover., October, 2004. Springer.
Abstract: This book provides a concise survey of principles and state-of-the-art techniques for secure group communications (SGC) over data networks. It offers an overview of secure algorithms and protocols for group communication linking areas such as applied cryptography and computer networking. Also included is a coverage of challenges in deploying secure group communication-based applications over wireless networks. These challenges include the limited computational power of mobile devices, susceptibility of wireless networks to intrusion and unauthorized access and mobility of nodes in a wireless ad-hoc network environment. **Secure Group Communications Over Data Networks** provides a wealth of information for network architects, IT Professionals, computer scientists, and advanced students of computer science and computer engineering in the fields of networking, computer security and software applications development.
BibTeX:
@book{ZoRM04-Secure,
  author = {X. Zou and Ramamurthy, Byrav and Magliveras, Spyros S.},
  title = {Secure Group Communications Over Data Networks},
  publisher = {Springer},
  year = {2004},
  note = {ISBN: 0387229701},
  url = {http://books.google.com/books?id=Kiy9estVV68C&printsec=frontcover&sig=ACfU3U2tyJ6xm09UZgdFaHUtZ7TnUTNy3A&source=gbs_ViewAPI},
  doi = {http://dx.doi.org/10.1007/b100182}
}
A. Todimala & Ramamurthy, B. (2004), "A Dynamic Partitioning Protection Routing Technique in WDM Networks", Cluster Computing., July, 2004. Vol. 7(3), pp. 259-269.
Abstract: With the increasing popularity of bandwidth-intensive applications, network traffic has been growing exponentially. Wavelength Division Multiplexing (WDM) is a technique that can harness the huge bandwidth available in an optical fiber to satisfy the network demand. Due to the multiplicity of the connections on any single link, fault tolerance is of utmost importance in such WDM networks. Active research on providing fault tolerance in WDM networks in recent times underscores its significance. In this study, a dynamic partitioning protection routing technique for routing a Fault Tolerant Path Set (FTPS) in a network is proposed. Wavelength assignment schemes to this FTPS with backup multiplexing technique for networks with no wavelength conversion and full wavelength conversion are discussed. Performance is measured in terms of blocking probability and time to recover the failed connections. Our simulations show that this protection technique performs better than other proposed techniques.
BibTeX:
@article{Todimala2004Dynamic,
  author = {A. Todimala and Ramamurthy, Byrav},
  title = {A Dynamic Partitioning Protection Routing Technique in WDM Networks},
  journal = {Cluster Computing},
  year = {2004},
  volume = {7},
  number = {3},
  pages = {259--269},
  url = {http://www.citeulike.org/pdf/user/byrav/article/3006808/todimala_04_dynamic.pdf},
  doi = {http://dx.doi.org/10.1023/B:CLUS.0000028004.03413.6b}
}
L. Shen, X. Yang & Ramamurthy, B. (2004), "Signaling Schemes for Distributed Connection Management in Wavelength-Routed Optical Mesh Networks", Photonic Network Communications., June, 2004. Vol. 8(1), pp. 89-103.
Abstract: The next-generation optical transport network will evolve from point-to-point connectivity to mesh networking, which can provide fast and automatic provisioning with enhanced flexibility and survivability. Signaling is used to support connection setup, maintenance, and teardown in such a network. In this paper, we study the performance of two hop-by-hop and one parallel signaling schemes in wavelength-routed optical mesh networks. Based on the sequence between optical crossconnect (OXC) switching and signaling message processing, we classify hop-by-hop signaling into two types that comply with the requirements of GMPLS signaling protocols. These two types are forward before switching configuration (FBSC) and forward after switching configuration (FASC). Also, we propose a parallel signaling scheme that is different from the existing hop-by-hop GMPLS signaling protocols. Considering OXC architectures and traffic patterns, we compare the FBSC, FASC, and parallel signaling schemes using simulation experiments, in terms of network blocking probability and reservation time. The simulation data reveal that the performance of a signaling scheme depends on the nature of the signaling as well as the network setting (e.g., the OXC architecture and traffic pattern). We analyze reasons for this result and discuss tradeoffs between these signaling schemes. This work offers some insight into designing an efficient signaling protocol for wavelength-routed optical mesh networks.
BibTeX:
@article{Shen2004Signaling,
  author = {L. Shen and X. Yang and Ramamurthy, Byrav},
  title = {Signaling Schemes for Distributed Connection Management in Wavelength-Routed Optical Mesh Networks},
  journal = {Photonic Network Communications},
  year = {2004},
  volume = {8},
  number = {1},
  pages = {89--103},
  url = {http://dx.doi.org/10.1023/B:PNET.0000031620.07210.d5},
  doi = {http://dx.doi.org/10.1023/B:PNET.0000031620.07210.d5}
}
W. Yao & Ramamurthy, B. (2004), "Constrained dynamic traffic grooming in WDM mesh networks with link bundled auxiliary graph model", In IEEE Workshop on High Performance Switching and Routing (HPSR). Phoenix, AZ, USA. April 2004., pp. 287-291.
Abstract: This paper addresses the two-layer routing problem in wavelength division multiplexed (WDM) optical mesh networks subject to resource constraints and generalized wavelength continuity (GWC) constraint. The GWC constraint is a relaxed wavelength continuity constraint in networks which have different kinds of wavelength conversion capabilities. As an improvement over the existing approach which represents each wavelength separately in the auxiliary graph, we introduce a largely simplified link bundled auxiliary graph (LBAG) and propose a new,method to find paths and assign wavelengths for new lightpaths subject to the GWC constraint. We propose a constrained grooming algorithm based on the LBAG model. We also propose two grooming policies which improve the existing grooming policies by integrating the wavelength and transceiver metrics and considering the relative resource utilization ratio. Simulations are conducted to evaluate the performance of the grooming policies in terms of blocking probability.
BibTeX:
@inproceedings{YaRa04hpsr-Constrained,
  author = {W. Yao and Ramamurthy, B.},
  title = {Constrained dynamic traffic grooming in WDM mesh networks with link bundled auxiliary graph model},
  booktitle = {IEEE Workshop on High Performance Switching and Routing (HPSR)},
  journal = {HPSR 2004. IEEE Workshop on High Performance Switching and Routing},
  year = {2004},
  pages = {287--291},
  url = {http://dx.doi.org/10.1109/HPSR.2004.1303491},
  doi = {http://dx.doi.org/10.1109/HPSR.2004.1303491}
}
X. Yang & Ramamurthy, B. (2004), "Inter-Domain Wavelength Routing in the Next-Generation Translucent Optical Internet Backbones", OSA Journal of Optical Networking (JON)., March, 2004. Vol. 3(3), pp. 169-187.
Abstract: Future home and enterprise Internet users need high-bandwidth end-to-end connections that have to be provisioned automatically and dynamically. We need to make optical-layer routing as scalable and flexible as IP routing in today's Internet to support high-end applications. We study the problem of interdomain dynamic wavelength routing based on a multidomain translucent optical network model, which allows end-to-end lightpaths to be set up not only across multiple routing domains but also through two network layers: the optical layer and the regeneration layer. In this model, a lightpath can traverse the domain boundary either through optical bypass (OOO) or through optical-electrical-optical regeneration (OEO). We propose an interdomain dynamic wavelength-routing scheme with modest computational complexity to address the problem from an algorithmic perspective. Our experimental results show that the proposed interdomain dynamic wavelength-routing scheme can (a) flexibly incorporate various cost metrics and local (or intradomain) routing schemes into a uniform interdomain routing framework, (b) effectively set up end-to-end lightpaths in a multidomain translucent network, and (c) efficiently use both optical- and regeneration-layer resources.
BibTeX:
@article{YaRa03JON--NSTD,
  author = {X. Yang and Ramamurthy, B.},
  title = {Inter-Domain Wavelength Routing in the Next-Generation Translucent Optical Internet Backbones},
  journal = {OSA Journal of Optical Networking (JON)},
  year = {2004},
  volume = {3},
  number = {3},
  pages = {169-187},
  doi = {doi:10.1364/JON.3.000169}
}
L. Shen, X. Yang & Ramamurthy, B. (2004), "A load-balancing shared-protection-path reconfiguration approach in WDM wavelength-routed networks", In Optical Fiber Communication Conference. February 2004., pp. 1-3. Optical Society of America.
Abstract: We propose a load-balancing shared-protection-path reconfiguration approach for WDM wavelength-routed networks, using which service providers can re-optimize the network utilization to postpone network upgrades, resulting in significant cost savings.
BibTeX:
@inproceedings{ShYR04ofc,
  author = {L. Shen and X. Yang and Ramamurthy, Byrav},
  title = {A load-balancing shared-protection-path reconfiguration approach in WDM wavelength-routed networks},
  booktitle = {Optical Fiber Communication Conference},
  publisher = {Optical Society of America},
  year = {2004},
  pages = {1--3},
  url = {http://www.opticsinfobase.org/abstract.cfm?id=110744},
  doi = {http://dx.doi.org/10.1109/OFC.2004.1362128}
}
X. Yang, L. Shen & Ramamurthy, B. (2004), "Maximizing resource sharing in WDM mesh networks with path-based protection and sparse OEO regeneration", In Optical Fiber Communication Conference. February 2004., pp. 1-3. Optical Society of America.
Abstract: We propose a resource-sharing scheme that supports three sharing scenarios in a WDM mesh network with path-based protection and sparse OEO regeneration. Several approaches are used to maximize the sharing of wavelength-links and OEO regenerators.
BibTeX:
@inproceedings{YaSR04ofc,
  author = {X. Yang and L. Shen and Ramamurthy, Byrav},
  title = {Maximizing resource sharing in WDM mesh networks with path-based protection and sparse OEO regeneration},
  booktitle = {Optical Fiber Communication Conference},
  publisher = {Optical Society of America},
  year = {2004},
  pages = {1--3},
  url = {http://www.opticsinfobase.org/abstract.cfm?id=110745},
  doi = {http://dx.doi.org/10.1109/OFC.2004.1362129}
}
X. Zou & Ramamurthy, B. (2004), "A block-free TGDH key agreement protocol for secure group communications", In International Conference on Parallel and Distributed Computing and Networks, PDCN 2004. Country of Publication: USA, January, 2004.
Abstract: Secure group communication (SGC) has been an active research area because several applications require it. In this paper, we propose a block-free group tree-based Diffie-Hellman (BF-TGDH) key agreement protocol, based on a recently proposed group tree-based Diffie-Hellman (TGDH) key agreement protocol, for secure group communication. The new protocol has the following specific properties: (1) no blocking during the rekeying process and seamless group communication without any interruption; (2) resistance to the man-in-the-middle attack; (3) authentication of message senders using inherent (ElGamal) signature protocol
BibTeX:
@incollection{8081429,
  author = {X. Zou and Ramamurthy, B},
  title = {A block-free TGDH key agreement protocol for secure group communications},
  booktitle = {International Conference on Parallel and Distributed Computing and Networks, PDCN 2004},
  year = {2004},
  note = {ISBN: 0889863695},
  url = {http://0-search.ebscohost.com.library.unl.edu:80/login.aspx?direct=true&38;db=inh&38;AN=8081429&38;site=ehost-live}
}
K. Ganesan & Ramamurthy, B. (2003), "Priority-based lambda scheduler", In ICC '03. IEEE International Conference on Communications. Volume 2, pp. 1479-1483.
Abstract: Optical networks provide a new dimension to meet the demands of exponentially growing traffic. Optical packet switching requires a good switch architecture, which eliminates the O/E/O conversion as much as possible. Wavelength division multiplexing (WDM) provides a breakthrough to exploit the huge bandwidth of the optical fiber. Different applications have different requirements, which necessitate employing differentiated services. This paper presents the idea of a priority-based /spl lambda/-scheduler, where the packets are differentiated into different classes and services are provided accordingly. For example, class 0 can correspond to non-real-time applications like email and ftp, while class 1 can correspond to real-time audio and video communications. The architecture is based on that of the /spl lambda/-scheduler and hence it has the added advantage of reduced component cost by using WDM internally.
BibTeX:
@inproceedings{GaRa03icc,
  author = {K. Ganesan and Ramamurthy, B.},
  title = {Priority-based lambda scheduler},
  booktitle = {ICC '03. IEEE International Conference on Communications},
  journal = {ICC '03. IEEE International Conference on Communications},
  year = {2003},
  volume = {2},
  pages = {1479--1483},
  url = {http://dx.doi.org/10.1109/ICC.2003.1204637},
  doi = {http://dx.doi.org/10.1109/ICC.2003.1204637}
}
M.K. Chirumamilla & Ramamurthy, B. (2003), "Agent based intrusion detection and response system for wireless LANs", In ICC '03: IEEE International Conference on Communications. Volume 1, pp. 492-496.
Abstract: Wireless LAN technology, despite the numerous advantages it has over competing technologies, has not seen widespread deployment. A primary reason for markets not adopting this technology is its failure to provide adequate security. Data that is sent over wireless links can be compromised with utmost ease. In this project, we propose a distributed agent based intrusion detection and response system for wireless LANs that can detect unauthorized wireless elements like access points, wireless clients that are in promiscuous mode etc. The system reacts to intrusions by either notifying the concerned personnel, in case of rogue access points and promiscuous nodes, or by blocking unauthorized users from accessing the network resources.
BibTeX:
@inproceedings{ChRa03icc,
  author = {M.K. Chirumamilla and Ramamurthy, B.},
  title = {Agent based intrusion detection and response system for wireless LANs},
  booktitle = {ICC '03: IEEE International Conference on Communications},
  journal = {ICC '03. IEEE International Conference on Communications},
  year = {2003},
  volume = {1},
  pages = {492--496},
  url = {http://dx.doi.org/10.1109/ICC.2003.1204225},
  doi = {http://dx.doi.org/10.1109/ICC.2003.1204225}
}
X. Yang & Ramamurthy, B. (2003), "Inter-domain dynamic routing in multi-layer optical transport networks", In GLOBECOM '03. IEEE Global Telecommunications Conference. Volume 5, pp. 2623-2627 vol.5.
Abstract: Next-generation optical transport networks will automatically and dynamically provision end-to-end connections. In this paper, we study the problem of inter-domain dynamic routing under a multi-layer multi-domain network model, which allows the end-to-end connections to be set up not only across multiple routing domains but also through two transport layers: the optical layer and the digital layer. In this model, a connection can traverse the domain boundary either through optical bypass or through optical-electrical-optical (O/E/O) processing. We propose an inter-domain dynamic routing scheme with modest time complexity to address the problem from an algorithmic perspective.
BibTeX:
@inproceedings{YaRa03globecom,
  author = {X. Yang and Ramamurthy, B.},
  title = {Inter-domain dynamic routing in multi-layer optical transport networks},
  booktitle = {GLOBECOM '03. IEEE Global Telecommunications Conference},
  journal = {GLOBECOM '03. IEEE Global Telecommunications Conference},
  year = {2003},
  volume = {5},
  pages = {2623--2627 vol.5},
  url = {http://dx.doi.org/10.1109/GLOCOM.2003.1258711},
  doi = {http://dx.doi.org/10.1109/GLOCOM.2003.1258711}
}
S. Zhang & Ramamurthy, B. (2003), "Dynamic traffic grooming algorithms for reconfigurable SONET over WDM networks", IEEE Journal on Selected Areas in Communications., In IEEE Journal on Selected Areas in Communications. Vol. 21(7), pp. 1165-1172.
Abstract: The emergence of wavelength-division multiplexing (WDM) technology provides the capability for increasing the bandwidth of synchronous optical network (SONET) rings by grooming low-speed traffic streams onto different high-speed wavelength channels. Since the cost of SONET add-drop multiplexers (SADM) at each node dominates the total cost of these networks, how to assign the wavelength, groom the traffic, and bypass the traffic through the intermediate nodes has received a lot of attention from researchers recently. Moreover, the traffic pattern of the optical network changes from time to time. How to develop dynamic reconfiguration algorithms for traffic grooming is an important issue. In this paper, two cases (best fit and full fit) for handling reconfigurable SONET over WDM networks are proposed. For each approach, an integer linear programming model and heuristic algorithms (TS-1 and TS-2, based on the tabu search method) are given. The results demonstrate that the TS-1 algorithm can yield better solutions but has a greater running time than the greedy algorithm for the best fit case. For the full fit case, the tabu search heuristic yields competitive results compared with an earlier simulated annealing based method and it is more stable for the dynamic case.
BibTeX:
@article{ZhRa03jsac,
  author = {S. Zhang and Ramamurthy, B.},
  title = {Dynamic traffic grooming algorithms for reconfigurable SONET over WDM networks},
  booktitle = {IEEE Journal on Selected Areas in Communications},
  journal = {IEEE Journal on Selected Areas in Communications},
  year = {2003},
  volume = {21},
  number = {7},
  pages = {1165--1172},
  url = {http://dx.doi.org/10.1109/JSAC.2003.815844},
  doi = {http://dx.doi.org/10.1109/JSAC.2003.815844}
}
K. Potharlanka, T. Antani, Ramamurthy, B., Sahasrabuddhe, L. & Mukherjee, B. (2003), "Design aspects of optical communication networks", In The Handbook of Optical Communication Networks (Electrical Engineering Handbook)., Hardcover., April, 2003. , pp. 45-66. CRC.
Abstract: The Internet revolution. Once, the public was delighted with 14.4 modem access and fascinated by low-tech Web site content. But not for long. Technology has raced to keep up with users' calls for high-speed facilities and advanced applications. With the development of high-speed transmission media and the availability of high-speed hardware, we are fast approaching the day when a single communication network will support all communication activities-and that network will use optical fibers as its transmission media and optical switch/routers as its nodes. The Handbook of Optical Communication Networks presents comprehensive, up-to-date technical information on integrated, state- of-the-art optical networks. Beginning with an in-depth intoduction to the field, top international authorities explore every major aspect of optical networks, from basic concepts to research grade material. Their discussions cover all of the essential topics, including protocols, resource management, routing and wavelength assignment in WDM networks, connection management, survivability, enabling technologies, and future trends. To meet the remaining technical and implementation challenges of optical networks, present and future communications professionals need a convenient, one-stop source for the relevant fundamentals, technical details, and applications. The Handbook of Optical Communication Networks provides that information in a presentation that is structured for fast access, organized for optimum utility, and packed with the insights of true leaders in the field.
BibTeX:
@incollection{InIlMo03-Design,
  author = {K. Potharlanka and T. Antani and Ramamurthy, Byrav and Sahasrabuddhe, Laxman and Mukherjee, Biswanath},
  title = {Design aspects of optical communication networks},
  booktitle = {The Handbook of Optical Communication Networks (Electrical Engineering Handbook)},
  publisher = {CRC},
  year = {2003},
  pages = {45--66},
  note = {ISBN: 0849313333},
  url = {http://www.amazon.ca/exec/obidos/redirect?tag=citeulike09-20&path=ASIN/0849313333}
}
X. Yang & Ramamurthy, B. (2003), "Inter-Domain Dynamic Routing in Translucent Optical Transport Networks", In IEEE INFOCOM High-Speed Networks (HSN) Workshop. April 2003., pp. 1-4.
BibTeX:
@inproceedings{YaRa03hsn,
  author = {X. Yang and Ramamurthy, B.},
  title = {Inter-Domain Dynamic Routing in Translucent Optical Transport Networks},
  booktitle = {IEEE INFOCOM High-Speed Networks (HSN) Workshop},
  year = {2003},
  pages = {1--4},
  url = {http://csce.unl.edu/~xyang/docs/InterDomainTranslucent.pdf}
}
Ramamurthy, B. (2003), "Electro-optic and wavelength conversion", In IP over WDM: Building the Next Generation Optical Internet., Hardcover., March, 2003. Wiley-Interscience.
Abstract: * The key technology to delivering maximum bandwidth over networks is Dense Wave-length Division Multiplexing (DWDM) * Describes in detail how DWDM works and how to implement a range of transmission protocols * Covers device considerations, the pros and cons of various network layer protocols, and quality of service (QoS) issues * The authors are leading experts in this field and provide real-world implementation examples * First book to describe the interplay between the physical and IP (Internet Protocol) layers in optical networks
BibTeX:
@incollection{InDixi03-Electro-optic,
  author = {Ramamurthy, Byrav},
  title = {Electro-optic and wavelength conversion},
  booktitle = {IP over WDM: Building the Next Generation Optical Internet},
  publisher = {Wiley-Interscience},
  year = {2003},
  note = {ISBN: 0471212482},
  url = {http://www.amazon.ca/exec/obidos/redirect?tag=citeulike09-20&path=ASIN/0471212482}
}
L. Shen & Ramamurthy, B. (2003), "Provisioning and Restoration in the Next-Generation Optical Core", Optical Networks Magazine., March, 2003. Vol. 4(2), pp. 32-45.
BibTeX:
@article{ShRa03onm-Provisioning,
  author = {L. Shen and Ramamurthy, Byrav},
  title = {Provisioning and Restoration in the Next-Generation Optical Core},
  journal = {Optical Networks Magazine},
  year = {2003},
  volume = {4},
  number = {2},
  pages = {32--45},
  url = {http://www.citeulike.org/pdf/user/byrav/article/3025879/shen_03_provisioning.pdf},
  doi = {http://dx.doi.org/10.1023/A:1022914606447}
}
X. Zou, Ramamurthy, B., Vinodchandran, N.V. & Balachandran, R.K. (2003), "Algorithms for unified hierarchy based access control", In International Conference on Communications, Internet, and Information Technology (CIIT). Country of Publication: USA, January, 2003.
Abstract: Access control is a fundamental security issue in any computer or communication system where there are users and resources. Recently a novel approach for access control, called unified hierarchy (UH), was proposed. We present algorithms for implementing unified hierarchy and combining two unified hierarchies into one. Further, we propose typical queries for unified hierarchy and show that most of these queries can be executed more efficiently in the unified hierarchy approach compared to other approaches for access control
BibTeX:
@incollection{8106603,
  author = {X. Zou and Ramamurthy, Byrav and Vinodchandran, N. V. and Balachandran, R. K.},
  title = {Algorithms for unified hierarchy based access control},
  booktitle = {International Conference on Communications, Internet, and Information Technology (CIIT)},
  year = {2003},
  url = {http://0-search.ebscohost.com.library.unl.edu:80/login.aspx?direct=true&db=inh&AN=8106603&site=ehost-live}
}
A. Todimala & Ramamurthy, B. (2003), "Congestion-based algorithms for online routing in optical WDM mesh networks", In International Conference on Communications, Internet, and Information Technology (CIIT). Country of Publication: USA, January, 2003.
Abstract: All-optical networks are becoming increasingly popular for high bandwidth connections. With the advent of the cross-connect technology, optical connections can be established dynamically. Routing and wavelength assignment are important issues in such networks. This paper focuses on the routing issue in networks. Two online algorithms are presented that compute a route among all feasible routes for a node pair based on hop length of the path and congestion in the network. Simulations are conducted on sample network topologies with Poisson traffic and exponential call holding times. Results show that shortest hop least congested routing technique performs better than other previous techniques in terms of blocking probability
BibTeX:
@incollection{8116544,
  author = {A. Todimala and Ramamurthy, Byrav},
  title = {Congestion-based algorithms for online routing in optical WDM mesh networks},
  booktitle = {International Conference on Communications, Internet, and Information Technology (CIIT)},
  year = {2003},
  url = {http://0-search.ebscohost.com.library.unl.edu:80/login.aspx?direct=true&38;db=inh&38;AN=8116544&38;site=ehost-live}
}
L. Shen, X. Yang & Ramamurthy, B. (2003), "Shared-risk link group (SRLG)-diverse path provisioning under hybrid service level agreements in wavelength-routed optical mesh networks: formulation and solution approaches", In SPIE OptiComm 2003: Optical Networking and Communications. Country of Publication: USA. January 2003. Volume 5285(1), pp. 126-138. SPIE-Int. Soc. Opt. Eng.
Abstract: The static provisioning problem in wavelength-routed optical networks has been studied for many years. However, service providers are still facing the challenges arising from the special requirements for provisioning services at the optical layer. In this paper, we incorporate some realistic constraints into the static provisioning problem, and formulate it under different network resource availability conditions. We consider three classes of shared risk link group (SRLG)- diverse path protection schemes: dedicated, shared, and unprotected. We associate with each connection request a lightpath length constraint and a revenue value. When the network resources are not sufficient to accommodate all the connection requests, the static provisioning problem is formulated as a revenue maximization problem, whose objective is maximizing the total revenue value. When the network has sufficient resources, the problem becomes a capacity minimization problem with the objective of minimizing the number of used wavelength-links. We give integer linear programming (ILP) formulations for these problems. Because solving these ILP problems is extremely time consuming, we propose a tabu search heuristic to solve these problems within a reasonable time. Experimental results are presented to compare the solutions obtained by an ILP solver, the tabu search heuristic and a divide-and-conquer greedy heuristic
BibTeX:
@inproceedings{8025725,
  author = {L. Shen and X. Yang and Ramamurthy, B.},
  title = {Shared-risk link group (SRLG)-diverse path provisioning under hybrid service level agreements in wavelength-routed optical mesh networks: formulation and solution approaches},
  booktitle = {SPIE OptiComm 2003: Optical Networking and Communications},
  publisher = {SPIE-Int. Soc. Opt. Eng},
  year = {2003},
  volume = {5285},
  number = {1},
  pages = {126--138},
  url = {http://search.ebscohost.com/login.aspx?direct=true&38;db=inh&38;AN=8025725&38;site=ehost-live}
}
Ramamurthy, B. & Jue, J. (2002), "Fiber, Lasers, Receivers, and Amplifiers", Optical WDM Networks. , pp. 27-50.
Abstract: The success of optical WDM networks depends heavily on the available optical device technology. This chapter is intended as an introduction to some of the optical device issues in WDM networks. It discusses the basic principles of optical transmission in fiber, and reviews the current state of the art in optical device technology.
BibTeX:
@incollection{Ramamurthy2002Fiber,
  author = {Ramamurthy, Byrav and Jue, Jason},
  title = {Fiber, Lasers, Receivers, and Amplifiers},
  journal = {Optical WDM Networks},
  year = {2002},
  pages = {27--50},
  url = {http://dx.doi.org/10.1007/0-306-47021-7_2},
  doi = {http://dx.doi.org/10.1007/0-306-47021-7_2}
}
Ramamurthy, B. (2002), "Switches, Wavelength Routers, and Wavelength Converters", Optical WDM Networks. , pp. 51-75.
Abstract: This chapter introduces some of the basic components in WDM networks, discusses various implementations of these components, and provides insights into their capabilities and limitations. The components discussed are fixed and reconfigurable wavelength routers, optical packet switches, and wavelength converters.
BibTeX:
@incollection{Ramamurthy2002Switches,
  author = {Ramamurthy, Byrav},
  title = {Switches, Wavelength Routers, and Wavelength Converters},
  journal = {Optical WDM Networks},
  year = {2002},
  pages = {51--75},
  url = {http://dx.doi.org/10.1007/0-306-47021-7_3},
  doi = {http://dx.doi.org/10.1007/0-306-47021-7_3}
}
S. Zhang & Ramamurthy, B. (2002), "Dynamic traffic grooming algorithms for reconfigurable SONET over WDM networks", In GLOBECOM '02. IEEE Global Telecommunications Conference. November 2002. Volume 3, pp. 2716-2720.
Abstract: The emergence of wavelength division multiplexing (WDM) technology provides the capability for increasing the bandwidth of synchronous optical network (SONET) rings by grooming low-speed traffic streams onto different high-speed wavelength channels. Since the cost of SONET add-drop multiplexers (SADM) at each node dominates the total cost of these networks, how to assign the wavelength, groom the traffic and bypass the traffic through the intermediate nodes has received a lot of attention from researchers recently. Moreover, the traffic pattern of the optical network changes from time to time. How to develop dynamic reconfiguration algorithms for traffic grooming is an important issue. We propose two cases (best-fit and full-fit) for handling reconfigurable SONET over WDM networks. For each approach, an integer linear programming model and heuristic algorithms (based on the tabu search method) are given. The results demonstrate that the tabu search heuristic can yield better solutions but has a greater running time than the greedy algorithm for the best-fit case. For the full-fit case, the tabu search heuristic yields competitive results compared with an earlier simulated annealing based method and it is more stable for the dynamic case.
BibTeX:
@inproceedings{ZhRa02globecom,
  author = {S. Zhang and Ramamurthy, B.},
  title = {Dynamic traffic grooming algorithms for reconfigurable SONET over WDM networks},
  booktitle = {GLOBECOM '02. IEEE Global Telecommunications Conference},
  journal = {GLOBECOM '02. IEEE Global Telecommunications Conference},
  year = {2002},
  volume = {3},
  pages = {2716--2720},
  url = {http://dx.doi.org/10.1109/GLOCOM.2002.1189123},
  doi = {http://dx.doi.org/10.1109/GLOCOM.2002.1189123}
}
N. Mohamed, A. Davis, X. Liu & Ramamurthy, B. (2002), "JOR: A Java Object Router", In Parallel and Distributed Computing and Systems (PDCS). Cambridge, MA. November 2002.(208), pp. 625-630.
Abstract: Content-based routing has emerged as a new routing paradigm, allowing messages to be routed based on defined fields within the message. Content-based routersg enerally employ XML. Each message is translated into XML when sent, and translated out of XML whenr eceived. Further, XML limits the objects sent to documents and messages. We introduce here a content based router that goes beyond messages to routing entireJ ava objects. The Java Object Router (JOR) separatesr outing mechanisms from routing policies, making it easy to use in a variety of applications.
BibTeX:
@inproceedings{MDLR02--NSTD,
  author = {N. Mohamed and A. Davis and X. Liu and Byrav Ramamurthy},
  title = {JOR: A Java Object Router},
  booktitle = {Parallel and Distributed Computing and Systems (PDCS)},
  year = {2002},
  number = {208},
  pages = {625-630},
  url = {http://www.actapress.com/Abstract.aspx?paperId=24636}
}
X. Yang & Ramamurthy, B. (2002), "An analytical model for virtual topology reconfiguration in optical networks and a case study", In ICCCN 2002: Eleventh International Conference on Computer Communications and Networks. October 2002., pp. 302-308.
Abstract: An analytical model for virtual topology reconfiguration (VTR) in optical networks is developed. It aims at the optical networks with a circuit-based data plane and an IP-like control plane. By identifying and analyzing the important factors impacting the network performance due to VTR operations on both planes, we can compare the benefits and penalties of different VTR algorithms and policies. The best VTR scenario can be adaptively chosen from a set of such algorithms and policies according to the real-time network situations. For this purpose, a cost model integrating all these factors is created to provide a comparison criterion independent of any specific VTR algorithm and policy. A case study based on simulation experiments is conducted to illustrate the application of our models.
BibTeX:
@inproceedings{YaRa02icccn,
  author = {X. Yang and Ramamurthy, B.},
  title = {An analytical model for virtual topology reconfiguration in optical networks and a case study},
  booktitle = {ICCCN 2002: Eleventh International Conference on Computer Communications and Networks},
  journal = {ICCCN 2002: Eleventh International Conference on Computer Communications and Networks},
  year = {2002},
  pages = {302--308},
  url = {http://dx.doi.org/10.1109/ICCCN.2002.1043082},
  doi = {http://dx.doi.org/10.1109/ICCCN.2002.1043082}
}
A. Todimala & Ramamurthy, B. (2002), "A Dynamic Partitioning Sub-Path Protection Routing Technique in WDM Mesh Networks", In ICCC '02: International Conference on Computer Communications. Mumbai, India. August 2002., pp. 327-340.
BibTeX:
@inproceedings{ToRa02,
  author = {A. Todimala and Byrav Ramamurthy},
  title = {A Dynamic Partitioning Sub-Path Protection Routing Technique in WDM Mesh Networks},
  booktitle = {ICCC '02: International Conference on Computer Communications},
  year = {2002},
  pages = {327-340}
}
Ramamurthy, B. (2002), "Review of Hui Zang's Thesis", Optical Networks Magazine., May, 2002. Vol. 3(3), pp. 109.
BibTeX:
@article{RamaONMMay02-Review,
  author = {Ramamurthy, Byrav},
  title = {Review of Hui Zang's Thesis},
  journal = {Optical Networks Magazine},
  year = {2002},
  volume = {3},
  number = {3},
  pages = {109},
  url = {http://www.citeulike.org/pdf/user/byrav/article/3032748/ramamurthy_02_review.pdf},
  doi = {http://dx.doi.org/10.1023/A:1017413816330}
}
L. Shen & Ramamurthy, B. (2002), "Centralized vs. distributed connection management schemes under different traffic patterns in wavelength-convertible optical networks", In ICC 2002. IEEE International Conference on Communications. April/May 2002. Volume 5, pp. 2712-2716.
Abstract: Centralized and distributed methods are two connection management schemes in wavelength convertible optical networks. In the earlier work, the centralized scheme is said to have lower network blocking probability than the distributed one. Hence, much of the previous work in connection management has focused on the comparison of different algorithms in only distributed scheme or in only centralized scheme. However, we believe that the network blocking probability of these two connection management schemes depends, to a great extent, on the network traffic patterns and reservation times. Our simulation results reveal that the performance improvement (in terms of blocking probability) of the centralized method over the distributed method is inversely proportional to the ratio of average connection inter-arrival time to reservation time. After that the ratio increases beyond a threshold, those two connection management schemes yield almost the same blocking probability under the same network load. In this paper, we review the working procedure of distributed and centralized schemes, discuss the tradeoff between them, compare these two methods under different network traffic patterns via simulation and give our conclusion based on the simulation data.
BibTeX:
@inproceedings{ShRa02icc,
  author = {L. Shen and Ramamurthy, B.},
  title = {Centralized vs. distributed connection management schemes under different traffic patterns in wavelength-convertible optical networks},
  booktitle = {ICC 2002. IEEE International Conference on Communications},
  journal = {ICC 2002. IEEE International Conference on Communications},
  year = {2002},
  volume = {5},
  pages = {2712--2716},
  url = {http://dx.doi.org/10.1109/ICC.2002.997336},
  doi = {http://dx.doi.org/10.1109/ICC.2002.997336}
}
X. Yang & Ramamurthy, B. (2002), "Dynamic routing in translucent WDM optical networks", In ICC 2002. IEEE International Conference on Communications. April/May 2002. Volume 5, pp. 2796-2802.
Abstract: Translucent WDM optical networks use sparse placement of regenerators to overcome the impairments and wavelength contention introduced by fully transparent networks, and achieve a performance close to fully opaque networks with much less cost. Our previous study proved the feasibility of translucent networks using the sparse regeneration technique. We addressed the placement of regenerators based on static schemes allowing only fixed number of regenerators at fixed locations. This paper furthers the study by proposing a suite of dynamical routing schemes. Dynamic allocation, advertisement and discovery of regeneration resources are proposed to support sharing transmitters and receivers between regeneration and access functions. This study follows the current trend in the optical networking industry by utilizing the extension of IP control protocols. Dynamic routing algorithms, aware of current regeneration resources and link states, are designed to smartly route the connection requests under quality constraints. A hierarchical network model, supported by the MPLS-based control plane, is also proposed to provide scalability. Experiments show that network performance is improved without placement of extra regenerators.
BibTeX:
@inproceedings{YaRa02icc,
  author = {X. Yang and Ramamurthy, B.},
  title = {Dynamic routing in translucent WDM optical networks},
  booktitle = {ICC 2002. IEEE International Conference on Communications},
  journal = {ICC 2002. IEEE International Conference on Communications},
  year = {2002},
  volume = {5},
  pages = {2796--2802},
  url = {http://dx.doi.org/10.1109/ICC.2002.997352},
  doi = {http://dx.doi.org/10.1109/ICC.2002.997352}
}
J.T. Lee & Ramamurthy, B. (2002), "A novel wavelength converter node architecture for WDM wavelength-routed networks", Optical Networks Magazine., March, 2002. Vol. 3(2), pp. 31-43.
BibTeX:
@article{LeRa02onm--NSTD,
  author = {J. T. Lee and Byrav Ramamurthy},
  title = {A novel wavelength converter node architecture for WDM wavelength-routed networks},
  journal = {Optical Networks Magazine},
  year = {2002},
  volume = {3},
  number = {2},
  pages = {31--43},
  url = {http://dx.doi.org/10.1023/A:1017404026744},
  doi = {http://dx.doi.org/10.1023/A:1017404026744}
}
Ramamurthy, B., Subramaniam, S. & Somani, A.K. (2002), "Guest Editorial - Special issue on Wavelength conversion", Optical Networks Magazine., March, 2002. Vol. 3(2), pp. 13.
BibTeX:
@article{RaSS02onm,
  author = {Byrav Ramamurthy and Suresh Subramaniam and Arun K. Somani},
  title = {Guest Editorial - Special issue on Wavelength conversion},
  journal = {Optical Networks Magazine},
  year = {2002},
  volume = {3},
  number = {2},
  pages = {13},
  url = {http://dx.doi.org/10.1023/A:1017404026744},
  doi = {http://dx.doi.org/10.1023/A:1017404026744}
}
X. Zou, Magliveras, S. & Ramamurthy, B. (2002), "A dynamic conference scheme extension with efficient burst operation", Thirty-Third Southeastern International Conference on Combinatorics, Graph Theory and Computing, Congressus Numerantium. Boca Raton, Florida, March, 2002. Vol. 158, pp. 83-92. Utilitas Mathematica Pub. Inc..
Abstract: Secure Group Communications (SGC) is becoming an extremely important research area because of its potentially enormous application paradigms. Symmetric polynomial based dynamic conference scheme is a typical technique for specific SGC applications. In this paper, we extend the symmetric polynomial based dynamic conference scheme. The extended scheme will allow any subset of users of any size to form a privileged subgroup, allow users to join and leave dynamically, and can perform bursty operation, especially when multiple users leave, in a very efficient way.
BibTeX:
@article{ZoMR02cnum-Dynamic,
  author = {X. Zou and S. Magliveras and B. Ramamurthy},
  title = {A dynamic conference scheme extension with efficient burst operation},
  journal = {Thirty-Third Southeastern International Conference on Combinatorics, Graph Theory and Computing, Congressus Numerantium},
  publisher = {Utilitas Mathematica Pub. Inc.},
  year = {2002},
  volume = {158},
  pages = {83--92}
}
X. Zou, Ramamurthy, B. & Magliveras, S. (2002), "Routing techniques in wireless ad hoc networks-classification and comparison", In 6th World Multiconference on Systemics, Cybernetics and Informatics. Country of Publication: USA, January, 2002. Vol. vol.4, pp. 84-89.
Abstract: Routing (and forwarding) is a core problem in networks for delivering data from one node to another. Today wireless networks are becoming popular because of their '3 Anys'- Any person, Anywhere and Any time. Wireless ad hoc networks are termed as mobile distributed multihop wireless networks without predetermined topology (preexisting fixed infrastructure) or central control. We present a comprehensive review for routing features and techniques in wireless ad hoc networks. For more than a dozen typical existing routing protocols, we compare their properties according to different criteria, and categorize them according to their routing strategies and relationships
BibTeX:
@incollection{7929140,
  author = {X. Zou and Ramamurthy, Byrav and Magliveras, S.},
  title = {Routing techniques in wireless ad hoc networks-classification and comparison},
  booktitle = {6th World Multiconference on Systemics, Cybernetics and Informatics},
  year = {2002},
  volume = {vol.4},
  pages = {84-89},
  url = {http://0-search.ebscohost.com.library.unl.edu:80/login.aspx?direct=true&db=inh&AN=7929140&site=ehost-live}
}
X. Zou, Ramamurthy, B. & Magliveras, S. (2002), "Efficient key management for secure group communications with bursty behavior", In International Conference on Communications, Internet, and Information Technology (CIIT). Country of Publication: USA, January, 2002.
Abstract: Secure group communication (SGC) is becoming more popular in the Internet. Burstiness is an important behavior in SGC. Performing bursty operation in one aggregate operation is important for efficiency and scalability. In this paper, we extend the well-known key-tree key management protocol for SGC to situations with bursty user arrival and departure patterns. By using a binary representation technique for indexing the keys and the members on the key tree, we propose an efficient algorithm for bursty operation. The algorithm uses only binary right shift operation, which is extremely simple and efficient and could be embedded in standard secure multicast API packages. We also present experimental results from our algorithm
BibTeX:
@incollection{7961546,
  author = {X. Zou and Ramamurthy, B. and Magliveras, S.},
  title = {Efficient key management for secure group communications with bursty behavior},
  booktitle = {International Conference on Communications, Internet, and Information Technology (CIIT)},
  year = {2002},
  url = {http://0-search.ebscohost.com.library.unl.edu:80/login.aspx?direct=true&38;db=inh&38;AN=7961546&38;site=ehost-live}
}
Ramamurthy, B. & A. Ramakrishnan (2002), "Design of virtual private networks (VPNs) over optical wavelength division multiplexed (WDM) networks", Optical Networks Magazine., January, 2002. Vol. 3(1), pp. 59-67.
BibTeX:
@article{RaRa02onm--NSTD,
  author = {Byrav Ramamurthy and A. Ramakrishnan},
  title = {Design of virtual private networks (VPNs) over optical wavelength division multiplexed (WDM) networks},
  journal = {Optical Networks Magazine},
  year = {2002},
  volume = {3},
  number = {1},
  pages = {59--67},
  url = {http://dx.doi.org/10.1023/A:1017484106556},
  doi = {http://dx.doi.org/10.1023/A:1017484106556}
}
Ramamurthy, B., S. Yaragorla & X. Yang (2001), "Translucent optical WDM networks for the next-generation backbone", In GLOBECOM '01. IEEE Global Telecommunications Conference. Volume 1, pp. 60-64 vol.1.
Abstract: This paper proposes an alternate approach to fully transparent and fully opaque optical networks for operating a wavelength routed optical network. The architecture of the regeneration node that performs sparse regeneration (or translucency) is discussed. The regeneration demands generated from call blocking and signal quality requirements are addressed. Two implementation strategies for incorporating sparse regeneration are introduced and their relative merits are studied
BibTeX:
@inproceedings{RaYY01globecom,
  author = {Ramamurthy, B. and S. Yaragorla and X. Yang},
  title = {Translucent optical WDM networks for the next-generation backbone},
  booktitle = {GLOBECOM '01. IEEE Global Telecommunications Conference},
  journal = {GLOBECOM '01. IEEE Global Telecommunications Conference},
  year = {2001},
  volume = {1},
  pages = {60--64 vol.1},
  url = {http://dx.doi.org/10.1109/GLOCOM.2001.965080},
  doi = {http://dx.doi.org/10.1109/GLOCOM.2001.965080}
}
G. Rao & Ramamurthy, B. (2001), "DiffServer: application level differentiated services for Web servers", In ICC 2001. IEEE International Conference on Communications. Volume 5, pp. 1633-1637.
Abstract: Web content hosting, in which a Web server stores and provides Web access to documents for different customers, is becoming increasingly common. For example, a Web server can host Web pages for several different companies and individuals. Traditionally, Web service providers (WSPs) provide all customers with the same level of performance (best-effort service). Most service differentiation has been in the pricing structure (individual vs. business rates) or the connectivity type (dial-up access vs. leased line, etc.). This report presents DiffServer, a program that implements two simple, server-side, application-level mechanisms (server-centric and client-centric) to provide different levels of Web service. The results of the experiments show that there is not much overhead due to the addition of this additional layer of abstraction between the client and the Apache Web server under light load conditions. Also, the average waiting time for high priority requests decreases significantly after they are assigned priorities as compared to a FIFO approach
BibTeX:
@inproceedings{RaRa01icc,
  author = {G. Rao and Ramamurthy, B.},
  title = {DiffServer: application level differentiated services for Web servers},
  booktitle = {ICC 2001. IEEE International Conference on Communications},
  journal = {ICC 2001. IEEE International Conference on Communications},
  year = {2001},
  volume = {5},
  pages = {1633--1637},
  url = {http://dx.doi.org/10.1109/ICC.2001.937196},
  doi = {http://dx.doi.org/10.1109/ICC.2001.937196}
}
X. Zou, Ramamurthy, B. & Magliveras, S. (2001), "Chinese Remainder Theorem Based Hierarchical Access Control for Secure Group Communication", In International Conference on Information and Communications Security (ICICS), Lecture Notes in Computer Science (LNCS). Vol. 2229/2001, pp. 381-385. Springer.
Abstract: Secure group communication with hierarchical access control refers to a scenario where a group of members is divided into a number of subgroups located at different privilege levels and a high-level subgroup can receive and decrypt messages within any of its descendant lower-level subgroups; but the converse is not allowed. In this paper, we propose a new scheme CRTHACS, which is based on the Chinese Remainder Theorem. The scheme not only enables secure hierarchical control but also provides the following properties: hiding of hierarchy and receivers, authentication of both senders and messages, and a mechanism for the receiver to directly derive the key of a message.
BibTeX:
@incollection{ZoRM2001icics,
  author = {X. Zou and Ramamurthy, Byrav and Magliveras, Spyros},
  title = {Chinese Remainder Theorem Based Hierarchical Access Control for Secure Group Communication},
  booktitle = {International Conference on Information and Communications Security (ICICS), Lecture Notes in Computer Science (LNCS)},
  publisher = {Springer},
  year = {2001},
  volume = {2229/2001},
  pages = {381--385},
  url = {http://dx.doi.org/10.1007/3-540-45600-7_42},
  doi = {http://dx.doi.org/10.1007/3-540-45600-7_42}
}
Birget, J.C., X. Zou, Noubir, G. & Ramamurthy, B. (2001), "Hierarchy-based access control in distributed environments", In ICC 2001. IEEE International Conference on Communications. Volume 1, pp. 229-233.
Abstract: Access control is a fundamental concern in any system that manages resources, e.g., operating systems, file systems, databases and communications systems. The problem we address is how to specify, enforce, and implement access control in distributed environments. This problem occurs in many applications such as management of distributed project resources, e-newspaper and pay TV subscription services. Starting from an access relation between users and resources, we derive a user hierarchy, a resource hierarchy, and a unified hierarchy. The unified hierarchy is then used to specify the access relation in a way that is compact and that allows efficient queries. It is also used in cryptographic schemes that enforce the access relation. We introduce three specific cryptography based hierarchical schemes, which can effectively enforce and implement access control and are designed for distributed environments because they do not need the presence of a central authority (except perhaps for setup)
BibTeX:
@inproceedings{BZNR01icc,
  author = {Birget, J. C. and X. Zou and Noubir, G. and Ramamurthy, B.},
  title = {Hierarchy-based access control in distributed environments},
  booktitle = {ICC 2001. IEEE International Conference on Communications},
  journal = {ICC 2001. IEEE International Conference on Communications},
  year = {2001},
  volume = {1},
  pages = {229--233},
  url = {http://dx.doi.org/10.1109/ICC.2001.936308},
  doi = {http://dx.doi.org/10.1109/ICC.2001.936308}
}
L. Zhong & Ramamurthy, B. (2001), "Optimization of amplifier placements in switch-based optical networks", In ICC 2001. IEEE International Conference on Communications. Volume 1, pp. 224-228.
Abstract: Wavelength division multiplexing (WDM) offers a solution to the problem of exploiting the large bandwidth on optical links; it is the current favorite multiplexing technology for optical communication networks. Due to the high cost of an optical amplifier, it is desirable to strategically place the amplifiers throughout the network in a way that guarantees that all the signals are adequately amplified while minimizing the total number amplifiers being used. Previous studies all consider a star-based network. This paper demonstrates an original approach for solving the problem in switch-based WDM optical network assuming the traffic matrix is always the permutation of the nodes. First we formulate the problem by choosing typical permutations which can maximize the traffic load on individual links; then a GA (genetic algorithm) is used to search for feasible amplifier placements. Finally, by setting up all the lightpaths without violating the power constraints we confirm the feasibility of the solution
BibTeX:
@inproceedings{ZhRa01icc,
  author = {L. Zhong and Ramamurthy, B.},
  title = {Optimization of amplifier placements in switch-based optical networks},
  booktitle = {ICC 2001. IEEE International Conference on Communications},
  journal = {ICC 2001. IEEE International Conference on Communications},
  year = {2001},
  volume = {1},
  pages = {224--228},
  url = {http://dx.doi.org/10.1109/ICC.2001.936307},
  doi = {http://dx.doi.org/10.1109/ICC.2001.936307}
}
X. Yang & Ramamurthy, B. (2001), "Sparse regeneration in a translucent WDM optical network", In SPIE Asia-Pacific Optical and Wireless Communications (APOC) Conference, Optical Networking. Beijing, China, November, 2001. Vol. 4585, pp. 61-70.
BibTeX:
@article{APOC01Rama--NSTD,
  author = {X. Yang and Byrav Ramamurthy},
  title = {Sparse regeneration in a translucent WDM optical network},
  booktitle = {SPIE Asia-Pacific Optical and Wireless Communications (APOC) Conference, Optical Networking},
  year = {2001},
  volume = {4585},
  pages = {61--70},
  url = {http://dx.doi.org/10.1117/12.445212}
}
Ramamurthy, B., L. Shen & E. Sawma (2001), "Connection management for wavelength-routed optical WDM networks", In Optical Networks: Recent Advances (Network Theory and Applications)., Hardcover., September, 2001. , pp. 187-204. Springer.
Abstract: Optical Networks with terabits per second bandwith have received significant interest from both researchers and practitioners. This book captures a collection of research and survey papers presenting the most recent developments in this exciting area. Contributions are from active researchers and cover a wide range of topics, including static and dynamic wavelength assignment algorithms, optimized wavelength converter allocation, traffic scheduling for QoS support, connection management, multicast routing, terabit packet switch architectures, multifiber networks, and multistage interconnection networks. The articles summarize the existing techniques, current developments and future directions as well as propose novel solutions to some important problems. Audience: The book is an ideal reference for researchers, engineers and students interested in optical networks to learn about current research activity and guide their own research.
BibTeX:
@incollection{InLuDu01-Connection,
  author = {Ramamurthy, Byrav and L. Shen and E. Sawma},
  title = {Connection management for wavelength-routed optical WDM networks},
  booktitle = {Optical Networks: Recent Advances (Network Theory and Applications)},
  publisher = {Springer},
  year = {2001},
  pages = {187--204},
  note = {ISBN: 0792371666},
  url = {http://books.google.com/books?id=j3pMjTCFJHYC&printsec=frontcover&sig=ACfU3U0gjWr-ZtNxZc9OLUdIgF5yMv4OjQ&source=gbs_ViewAPI}
}
Szymanski, A. (2001), "Design of optical WDM networks. LAN, MAN and WAN architectures: BOOK REVIEW.", IEEE Communications Magazine., September, 2001. Vol. 39(9), pp. 20-.
Abstract: Reviews the book `Design of Optical WDM Networks: LAN, MAN and WAN Architectures,' by Byrav Ramamurthy.
BibTeX:
@article{Szymanski2001Design,
  author = {Szymanski, Andrzej},
  title = {Design of optical WDM networks. LAN, MAN and WAN architectures: BOOK REVIEW.},
  journal = {IEEE Communications Magazine},
  year = {2001},
  volume = {39},
  number = {9},
  pages = {20--},
  url = {http://dx.doi.org/10.1109/MCOM.2001.948378},
  doi = {http://dx.doi.org/10.1109/MCOM.2001.948378}
}
Sivalingam, K. (2001), "Book Review of Design of Optical WDM Networks", Optical Networks Magazine., July, 2001. Vol. 2(4), pp. 115.
Abstract: Reviews the book `Design of Optical WDM Networks: LAN, MAN and WAN Architectures,' by Byrav Ramam\ urthy.
BibTeX:
@article{SivaONMJul01-Rama01BookReview,
  author = {Sivalingam, Krishna},
  title = {Book Review of Design of Optical WDM Networks},
  journal = {Optical Networks Magazine},
  year = {2001},
  volume = {2},
  number = {4},
  pages = {115},
  url = {http://www.citeulike.org/pdf/user/byrav/article/3032700/sivalingam_01_book.pdf},
  doi = {http://dx.doi.org/10.1023/A:1017292115868}
}
Ramamurthy, B. (2001), "Review of Jonathan P. Lang's Thesis", Optical Networks Magazine., March, 2001. Vol. 2(2), pp. 16-17.
BibTeX:
@article{RamaONMMar01-Review,
  author = {Ramamurthy, Byrav},
  title = {Review of Jonathan P. Lang's Thesis},
  journal = {Optical Networks Magazine},
  year = {2001},
  volume = {2},
  number = {2},
  pages = {16--17},
  url = {http://www.citeulike.org/pdf/user/byrav/article/3032747/ramamurthy_01_review.pdf},
  doi = {http://dx.doi.org/10.1023/A:1017288014960}
}
X. Yang & Ramamurthy, B. (2001), "Sparse regeneration in a translucent WDM optical network", In SPIE Asia-Pacific Optical and Wireless Communications (APOC) Conference, Optical Networking. Country of Publication: USA. January 2001. Volume 4585, pp. 61-70. SPIE-Int. Soc. Opt. Eng SPIE..
Abstract: Research implies that transparent optical WDM networks have difficulty in overcoming transmission impairments introduced by long-haul fibers and cascading optical components while opaque networks are not cost-efficient because a large number of wavelengths need optical-electronic and electronic-optical conversions at every intermediate node. This paper proposes an alternate approach to fully transparent and fully opaque optical networks for operating a wavelength routed optical network. The architecture of regeneration node that performs sparse regeneration (or translucency) is modeled. Both static and dynamic regeneration schemes are discussed. The regeneration demands generated from call blocking and signal quality requirements are addressed. Two implementation strategies for incorporating sparse regeneration are introduced and algorithms are proposed for the regenerator placement, and their relative merits are studied
BibTeX:
@inproceedings{7337487,
  author = {X. Yang and Ramamurthy, B.},
  title = {Sparse regeneration in a translucent WDM optical network},
  booktitle = {SPIE Asia-Pacific Optical and Wireless Communications (APOC) Conference, Optical Networking},
  publisher = {SPIE-Int. Soc. Opt. Eng SPIE.},
  year = {2001},
  volume = {4585},
  pages = {61--70},
  url = {http://0-search.ebscohost.com.library.unl.edu:80/login.aspx?direct=true&38;db=inh&38;AN=7337487&38;site=ehost-live}
}
Ramamurthy, B. (2001), "Design of Optical WDM Networks - LAN, MAN and WAN Architectures", Hardcover. Boston, MA, January, 2001. , pp. 166+ pg.. Springer.
Abstract: Wavelength Division Multiplexed (WDM) optical networks are emerging as promising candidates for the infrastructure of the next-generation Internet. Such networks are envisaged for spanning local, metropolitan and wide geographical areas. WDM optical networks go beyond technologies such as Synchronous Optical Network (SONET) and Asynchronous Transfer Mode (ATM) in realizing the full potential of the optical medium. From passive star coupler- based broadcast optical networks to switch-based optical wavelength-routed networks, the book covers a wide range of available technologies and designs for proposed network architectures. The author investigates the impact of physical-layer issues on the design of such WDM-based optical networks. In particular, this book presents a sampling of problems such as amplifier placement and optimization, sharing and minimization of wavelength converter usage, and bit-error rate (BER)-based all-admission in WDM optical networks and proposes novel solutions. Efficient algorithms are described which significantly improve the cost-effectiveness of WDM networks. Design of Optical WDM Networks: LAN, MAN and WAN Architectures is targeted towards practitioners and researchers in the field of optical networks and WDM as well as students interested in the future of networking and telecommunications.
BibTeX:
@book{Rama01-Design,
  author = {Ramamurthy, Byrav},
  title = {Design of Optical WDM Networks - LAN, MAN and WAN Architectures},
  publisher = {Springer},
  year = {2001},
  pages = {166+ pg.},
  note = {ISBN: 0792372816. (Reviews of this book have appeared in IEEE Communications magazine (Sep. 2001) and Optical Networks magazine (July 2001).)},
  url = {http://www.springer.com/computer/communications/book/978-0-7923-7281-3}
}
Ramamurthy, B. (2001), "Review of Laxman Sahasrabuddhe's Thesis", Optical Networks Magazine., January, 2001. Vol. 2(1), pp. 23-25.
BibTeX:
@article{RamaONMJan01-Review,
  author = {Ramamurthy, Byrav},
  title = {Review of Laxman Sahasrabuddhe's Thesis},
  journal = {Optical Networks Magazine},
  year = {2001},
  volume = {2},
  number = {1},
  pages = {23--25},
  url = {http://www.citeulike.org/pdf/user/byrav/article/3032745/ramamurthy_01_review.pdf},
  doi = {http://dx.doi.org/10.1023/A:1017267230889}
}
Ramamurthy, B. & Jue, J. (2000), "Fiber, Lasers, Receivers, and Amplifiers", In Optical WDM Networks: Principles and Practice. Boston, MA , pp. 27-50. Kluwer Academic Publishers.
Abstract: The success of optical WDM networks depends heavily on the available optical device technology. This chapter is intended as an introduction to some of the optical device issues in WDM networks. It discusses the basic principles of optical transmission in fiber, and reviews the current state of the art in optical device technology.
BibTeX:
@incollection{RaJu02-Fiber,
  author = {Ramamurthy, Byrav and Jue, Jason},
  title = {Fiber, Lasers, Receivers, and Amplifiers},
  booktitle = {Optical WDM Networks: Principles and Practice},
  publisher = {Kluwer Academic Publishers},
  year = {2000},
  pages = {27--50},
  note = {ISBN: 0792378253},
  url = {http://dx.doi.org/10.1007/0-306-47021-7_2},
  doi = {http://dx.doi.org/10.1007/0-306-47021-7_2}
}
Ramamurthy, B. (2000), "Switches, Wavelength Routers, and Wavelength Converters", In Optical WDM Networks: Principles and Practice. Boston, MA , pp. 51-75. Kluwer Academic Publishers.
Abstract: This chapter introduces some of the basic components in WDM networks, discusses various implementations of these components, and provides insights into their capabilities and limitations. The components discussed are fixed and reconfigurable wavelength routers, optical packet switches, and wavelength converters.
BibTeX:
@incollection{Rama02-Switches,
  author = {Ramamurthy, Byrav},
  title = {Switches, Wavelength Routers, and Wavelength Converters},
  booktitle = {Optical WDM Networks: Principles and Practice},
  publisher = {Kluwer Academic Publishers},
  year = {2000},
  pages = {51--75},
  note = {ISBN: 0792378253},
  url = {http://dx.doi.org/10.1007/0-306-47021-7_3},
  doi = {http://dx.doi.org/10.1007/0-306-47021-7_3}
}
T. Schroeder, Goddard, S. & Ramamurthy, B. (2000), "Scalable Web server clustering technologies", IEEE Network., In Network, IEEE. Vol. 14(3), pp. 38-45.
Abstract: The exponential growth of the Internet, coupled with the increasing popularity of dynamically generated content on the World Wide Web, has created the need for more and faster Web servers capable of serving the over 100 million Internet users. Server clustering has emerged as a promising technique to build scalable Web servers. We examine the seminal work, early products, and a sample of contemporary commercial offerings in the field of transparent Web server clustering. We broadly classify transparent server clustering into three categories
BibTeX:
@article{ScGR00net,
  author = {T. Schroeder and Goddard, S. and Ramamurthy, B.},
  title = {Scalable Web server clustering technologies},
  booktitle = {Network, IEEE},
  journal = {IEEE Network},
  year = {2000},
  volume = {14},
  number = {3},
  pages = {38--45},
  url = {http://dx.doi.org/10.1109/65.844499},
  doi = {http://dx.doi.org/10.1109/65.844499}
}
Somani, A.K. & Ramamurthy, B. (2000), "Guest editorial - Optical communication networks for the next-generation Internet", IEEE Network., In Network, IEEE. Vol. 14(6), pp. 6-7.
BibTeX:
@article{SoRa00net,
  author = {Somani, A. K. and Ramamurthy, B.},
  title = {Guest editorial - Optical communication networks for the next-generation Internet},
  booktitle = {Network, IEEE},
  journal = {IEEE Network},
  year = {2000},
  volume = {14},
  number = {6},
  pages = {6--7},
  url = {http://dx.doi.org/10.1109/MNET.2000.885664},
  doi = {http://dx.doi.org/10.1109/MNET.2000.885664}
}
Ramamurthy, B. & A. Ramakrishnan (2000), "Virtual topology reconfiguration of wavelength-routed optical WDM networks", In GLOBECOM '00. IEEE Global Telecommunications Conference. November/December 2000. Volume 2, pp. 1269-1275.
Abstract: The bandwidth requirements of the Internet are increasing every day and there are newer and more bandwidth-thirsty applications emerging on the horizon. Wavelength division multiplexing (WDM) is the next step towards leveraging the capabilities of the optical fiber, especially for wide-area backbone networks. The ability to switch a signal at intermediate nodes in a WDM network based on their wavelengths is known as wavelength-routing. One of the greatest advantages of using wavelength-routing WDM is the ability to create a virtual topology different from the physical topology of the underlying network. This virtual topology can be reconfigured when necessary, to improve performance. We discuss the previous work done on virtual topology design and also discuss and propose different reconfiguration algorithms applicable under different scenarios
BibTeX:
@inproceedings{RaRa00globecom,
  author = {Ramamurthy, B. and A. Ramakrishnan},
  title = {Virtual topology reconfiguration of wavelength-routed optical WDM networks},
  booktitle = {GLOBECOM '00. IEEE Global Telecommunications Conference},
  journal = {GLOBECOM '00. IEEE Global Telecommunications Conference},
  year = {2000},
  volume = {2},
  pages = {1269--1275},
  url = {http://dx.doi.org/10.1109/GLOCOM.2000.891340},
  doi = {http://dx.doi.org/10.1109/GLOCOM.2000.891340}
}
X. Gan, T. Schroeder, Goddard, S. & Ramamurthy, B. (2000), "LSMAC vs. LSNAT: Scalable cluster-based Web servers", Cluster Computing., November, 2000. Vol. 3(3), pp. 175-185.
Abstract: Abstract Server scalability is more important than ever in today's client/server dominated network environments. Recently, researchers have begun to consider cluster-based computers using commodity hardware as an alternative to expensive specialized hardware for building scalable Web servers. In this paper, we present performance results comparing two cluster-based Web servers based on different server architectures: OSI layer two dispatching (LSMAC) and OSI layer three dispatching (LSNAT). Both cluster-based server systems were implemented as application-space programs running on commodity hardware in contrast to other, similar, solutions which require specialized hardware/software. We point out the advantages and disadvantages of both systems. We also identify when servers should be clustered and when clustering will not improve performance.
BibTeX:
@article{GSGR2000LSMAC,
  author = {X. Gan and T. Schroeder and Goddard, Steve and Ramamurthy, Byrav},
  title = {LSMAC vs. LSNAT: Scalable cluster-based Web servers},
  journal = {Cluster Computing},
  year = {2000},
  volume = {3},
  number = {3},
  pages = {175--185},
  url = {http://www.citeulike.org/pdf/user/byrav/article/3006819/gan_00_lsmac.pdf},
  doi = {http://dx.doi.org/10.1023/A:1019084304980}
}
Ramamurthy, B. (2000), "Virtual Private Networks (VPNs) over Optical WDM Wavelength-routed Networks", In IEEE Computer Communications (CCW) Workshop. Captiva Island, FL. October 2000.
BibTeX:
@inproceedings{Rama00c--NSTD,
  author = {Byrav Ramamurthy},
  title = {Virtual Private Networks (VPNs) over Optical WDM Wavelength-routed Networks},
  booktitle = {IEEE Computer Communications (CCW) Workshop},
  year = {2000}
}
X. Gan & Ramamurthy, B. (2000), "LSMAC: An improved load sharing network service dispatcher", World Wide Web., July, 2000. Vol. 3(1), pp. 53-59.
Abstract: Abstract The rapid growth of the Internet is changing the way we do business. Electronic Commerce (or E-Commerce) is already a reality and will expand rapidly in the near future. However, the success of E-Commerce depends heavily on the scalability and availability of the servers. Cluster-based servers using commodity hardware have been accepted as a good alternative to expensive specialized hardware for building scalable services. In this paper, we summarize the two clustering architectures: IP-based clustering and MAC-based clustering. A new efficient implementation of the MAC-based clustering architecture is presented and its performance in clustering Web servers was measured using the WebStone benchmark and was found to be superior to that of existing MAC-based clustering implementations.
BibTeX:
@article{GaRa2000LSMAC,
  author = {X. Gan and Ramamurthy, Byrav},
  title = {LSMAC: An improved load sharing network service dispatcher},
  journal = {World Wide Web},
  year = {2000},
  volume = {3},
  number = {1},
  pages = {53--59},
  url = {http://www.citeulike.org/pdf/user/byrav/article/3006818/gan_00_lsmac.pdf},
  doi = {http://dx.doi.org/10.1023/A:1019225512000}
}
X. Gan, T. Schroeder, Goddard, S. & Ramamurthy, B. (2000), "LSMAC and LSNAT: Two approaches for cluster-based scalable Web servers", In ICC 2000. IEEE International Conference on Communications. June 2000. Volume 2, pp. 1164-1168.
Abstract: Server responsiveness and scalability are more important than ever in today's client/server dominated network environments. Researchers have begun to consider cluster-based computers using commodity hardware as an alternative to expensive specialized hardware for building scalable Web servers. In this paper, we present performance results comparing two cluster-based Web servers based on different server infrastructures: MAC-based dispatching (LSMAC) and IP-based dispatching (LSNAT). Both cluster-based server systems were implemented as application-space programs running on commodity hardware. We point out the advantages and disadvantages of both systems. We also identify when servers should be clustered and when clustering will not improve performance
BibTeX:
@inproceedings{GSGR00icc,
  author = {X. Gan and T. Schroeder and Goddard, S. and Ramamurthy, B.},
  title = {LSMAC and LSNAT: Two approaches for cluster-based scalable Web servers},
  booktitle = {ICC 2000. IEEE International Conference on Communications},
  journal = {ICC 2000. IEEE International Conference on Communications},
  year = {2000},
  volume = {2},
  pages = {1164--1168},
  url = {http://dx.doi.org/10.1109/ICC.2000.853680},
  doi = {http://dx.doi.org/10.1109/ICC.2000.853680}
}
M. Ali, Ramamurthy, B. & Deogun, J.S. (2000), "Routing and wavelength assignment with power considerations in optical networks", Computer Networks., May, 2000. Vol. 32(5), pp. 539-555.
Abstract: Previous studies have solved many variations of the routing and wavelength assignment (RWA) problem in optical networks under the assumption of perfect conditions regarding the power of a signal. In this paper, we investigate the RWA problem while allowing for degradation of routed signals by optical components. The problem is formulated as a mixed-integer non-linear program. We propose a two-phase approach. In the first phase, we solve the pure RWA problem using fixed routes for every connection. In the second phase, power assignment is accomplished by either using a heuristic or using a genetic algorithm. This paper demonstrates that: (i) connections do interact affecting the power of each other, and (ii) global search meta-heuristics provide better solutions.
BibTeX:
@article{AlRD00cnet,
  author = {M. Ali and Ramamurthy, Byrav and Deogun, Jitender S.},
  title = {Routing and wavelength assignment with power considerations in optical networks},
  journal = {Computer Networks},
  year = {2000},
  volume = {32},
  number = {5},
  pages = {539--555},
  url = {http://dx.doi.org/10.1016/S1389-1286(00)00015-3},
  doi = {http://dx.doi.org/10.1016/S1389-1286(00)00015-3}
}
J.T. Lee & Ramamurthy, B. (2000), "A novel hybrid wavelength converter node architecture for WDM wavelength-routed networks", In Optical Networks Workshop (ONW 2000). January 2000.
BibTeX:
@inproceedings{LeRa00--NSTD,
  author = {J. T. Lee and Byrav Ramamurthy},
  title = {A novel hybrid wavelength converter node architecture for WDM wavelength-routed networks},
  booktitle = {Optical Networks Workshop (ONW 2000)},
  year = {2000}
}
Ramamurthy, B. & A. Ramakrishnan (2000), "Design of virtual private networks (VPNs) over optical wavelength-division-multiplexed (WDM) networks", In SPIE Opticomm 2000: Optical Networking and Communications Conference. Richardson, TX, USA. January 2000. Volume 4233, pp. 76-86. SPIE-Int. Soc. Opt. Eng.
Abstract: The bandwidth requirements of the Internet are increasing every day and there are newer and more bandwidth-thirsty applications emerging on the horizon. Wavelength division multiplexing (WDM) is the next step towards leveraging the capabilities of the optical fiber, especially for wide-area backbone networks. Virtual private networks are seen as the killer applications of tomorrow, and a great amount of research and development effort is being channeled into finding efficient ways for implementing them. In our work, we introduce the notion of VPNs operating over optical wavelength-routed WDM backbone networks. We formulate the problem of VPN design over optical WDM networks as an integer linear problem. A new method to deal with traffic from diverse VPNs is introduced and its performance analyzed
BibTeX:
@inproceedings{RaRa00o,
  author = {Ramamurthy, B. and A. Ramakrishnan},
  title = {Design of virtual private networks (VPNs) over optical wavelength-division-multiplexed (WDM) networks},
  booktitle = {SPIE Opticomm 2000: Optical Networking and Communications Conference},
  journal = {Proceedings of the SPIE - The International Society for Optical Engineering},
  publisher = {SPIE-Int. Soc. Opt. Eng},
  year = {2000},
  volume = {4233},
  pages = {76--86},
  url = {http://search.ebscohost.com/login.aspx?direct=true&38;db=inh&38;AN=6914017&38;site=ehost-live}
}
Ramamurthy, B., Datta, D., Feng, H., Heritage, J.P. & Mukherjee, B. (1999), "Impact of transmission impairments on the teletraffic performance of wavelength-routed optical networks", IEEE/OSA Journal of Lightwave Technology., In IEEE/OSA Journal of Lightwave Technology. Vol. 17(10), pp. 1713-1723.
Abstract: In a wavelength-routed optical network, a transmitted signal remains in the optical domain over the entire route (lightpath) assigned to it between its source and destination nodes. The optical signal may have to traverse a number of crossconnect switches (XCSs), fiber segments, and optical amplifiers, e.g., erbium-doped fiber amplifiers (EDFAs). Thus, while propagating through the network, the signal may degrade in quality as it encounters crosstalk at the XCSs and also picks up amplified spontaneous emission (ASE) noise at the EDFAs. Since these impairments continue to degrade the signal quality as it progresses toward its destination, the received bit error rate (BER) at the destination node might become unacceptably high. Previous work on the lightpath routing and wavelength assignment (RWA) problem assumed an ideal physical layer and ignored these transmission impairments. The main contribution of our work is to incorporate the role of the physical layer in setting up lightpaths by employing appropriate models of multiwavelength optical devices (XCSs and EDFAs) such that the BER of a candidate lightpath can be computed, in advance, to determine if this lightpath should be used for the call. Features from existing RWA algorithms are integrated with our on-line BER calculation mechanism. Our simulation studies indicate that employing BER-based call-admission algorithms has a significant impact on the performance of realistic networks
BibTeX:
@article{Rama99jlt,
  author = {Ramamurthy, B. and Datta, D. and Feng, H. and Heritage, J. P. and Mukherjee, B.},
  title = {Impact of transmission impairments on the teletraffic performance of wavelength-routed optical networks},
  booktitle = {IEEE/OSA Journal of Lightwave Technology},
  journal = {IEEE/OSA Journal of Lightwave Technology},
  year = {1999},
  volume = {17},
  number = {10},
  pages = {1713--1723},
  url = {http://dx.doi.org/10.1109/50.793740},
  doi = {http://dx.doi.org/10.1109/50.793740}
}
M. Ali, Ramamurthy, B. & Deogun, J.S. (1999), "Routing and wavelength assignment (RWA) with power considerations in all-optical wavelength-routed networks", In GLOBECOM 1999. IEEE Global Telecommunications Conference. December 1999. Volume 2, pp. 1433-1437.
Abstract: Routing and wavelength assignment (RWA) is an important problem that arises in wavelength division multiplexed (WDM) optical networks. Previous studies have solved many variations of this problem under the assumption of perfect conditions regarding the power of a signal. We investigate this problem while allowing for degradation of routed signals by components such as taps, multiplexers, and fiber links. We assume that optical amplifiers are preplaced. We investigate the problem of routing the maximum number of connections while maintaining proper power levels. The problem is formulated as a mixed-integer nonlinear program and two-phase hybrid solution approaches employing two different heuristics are developed
BibTeX:
@inproceedings{AlRD99globecom,
  author = {M. Ali and Ramamurthy, B. and Deogun, J. S.},
  title = {Routing and wavelength assignment (RWA) with power considerations in all-optical wavelength-routed networks},
  booktitle = {GLOBECOM 1999. IEEE Global Telecommunications Conference},
  journal = {GLOBECOM '99: IEEE Global Telecommunications Conference},
  year = {1999},
  volume = {2},
  pages = {1433--1437},
  url = {http://dx.doi.org/10.1109/GLOCOM.1999.830014},
  doi = {http://dx.doi.org/10.1109/GLOCOM.1999.830014}
}
M. Ali, Ramamurthy, B. & Deogun, J.S. (1999), "Routing algorithms for all-optical networks with power considerations: the unicast case", In ICCCN 1999. Eighth International Conference on Computer Communications and Networks. October 1999., pp. 237-241.
Abstract: In this paper, we investigate the problem of routing connections in ail-optical networks while allowing for degradation of routed signals by different optical components. To overcome the complexity of the problem, we divide it into two parts. First, we solve the pure RWA problem using fixed routes for every connection. Second, power assignment is accomplished by either using the smallest-gain first (SGF) heuristic or using a genetic algorithm. Numerical examples on a wide variety of networks show that: (a) the number of connections established without considering the signal attenuation was most of the time greater than that achievable considering attenuation; and (b) the genetic solution quality was much better than that of SGF, especially when the conflict graph of the connections generated by the linear solver is denser
BibTeX:
@inproceedings{AlRD99icccn,
  author = {M. Ali and Ramamurthy, B. and Deogun, J. S.},
  title = {Routing algorithms for all-optical networks with power considerations: the unicast case},
  booktitle = {ICCCN 1999. Eighth International Conference on Computer Communications and Networks},
  journal = {ICCCN 1999: Eighth International Conference on Computer Communications and Networks},
  year = {1999},
  pages = {237--241},
  url = {http://dx.doi.org/10.1109/ICCCN.1999.805525},
  doi = {http://dx.doi.org/10.1109/ICCCN.1999.805525}
}
Ramamurthy, B., Datta, D., Feng, H., Heritage, J.P. & Mukherjee, B. (1999), "SIMON: A SIMulator for Optical Networks", In IEEE Computer Communications (CCW) Workshop. Estes Park, CO. October 1999.
BibTeX:
@inproceedings{Rama99_CCW--NSTD,
  author = {Byrav Ramamurthy and Debasish Datta and Helena Feng and Jonathan P. Heritage and Biswanath Mukherjee},
  title = {SIMON: A SIMulator for Optical Networks},
  booktitle = {IEEE Computer Communications (CCW) Workshop},
  year = {1999}
}
Ramamurthy, B., Datta, D., Feng, H., Heritage, J.P. & Mukherjee, B. (1999), "SIMON: a simulator for optical networks", In Proceedings of the SPIE - All Optical Networking 1999: Architecture, Control and Management Issues. Country of Publication: USA. September 1999. Volume 3843, pp. 130-135. SPIE-Int. Soc. Opt. Eng SPIE..
Abstract: SIMON is an object-oriented event-driven simulation package implemented in C++ which incorporates optical device characteristics in the measurement of network-level blocking statistics. SIMON is suitable for studying the performance of large wavelength-routed optical networks, in which a call is set up in the network for a specific duration on a pre-determined lightpath. Currently the physical-layer models allow for modeling phenomena such as signal attenuation in fiber and other components, amplifier gain saturation, and homowavelength crosstalk in switches. Simulation experiments can be performed with a user-specified bit-error rate limit, which must be satisfied by any call set up in the network
BibTeX:
@inproceedings{6484811,
  author = {Ramamurthy, B. and Datta, D. and Feng, H. and Heritage, J. P. and Mukherjee, B.},
  title = {SIMON: a simulator for optical networks},
  booktitle = {Proceedings of the SPIE - All Optical Networking 1999: Architecture, Control and Management Issues},
  publisher = {SPIE-Int. Soc. Opt. Eng SPIE.},
  year = {1999},
  volume = {3843},
  pages = {130--135},
  url = {http://search.ebscohost.com/login.aspx?direct=true&38;db=inh&38;AN=6484811&38;site=ehost-live}
}
Ramamurthy, B., Feng, H., Datta, D., Heritage, J.P. & Mukherjee, B. (1999), "Transparent vs. opaque vs. translucent wavelength-routed optical networks", In Optical Fiber Communication Conference, 1999, and the International Conference on Integrated Optics and Optical Fiber Communication. OFC/IOOC '99. Technical Digest. February 1999. Volume 1, pp. 59-61 vol.1.
Abstract: This study evaluates the relative merits of three approaches (transparency, opacity, and translucency) for establishing calls in a wavelength-routed optical network. Call-admission algorithms employ online bit-error-rate computation and include the effects of transmission impairments
BibTeX:
@inproceedings{Rama99ofc-Transparent,
  author = {Ramamurthy, B. and Feng, H. and Datta, D. and Heritage, J. P. and Mukherjee, B.},
  title = {Transparent vs. opaque vs. translucent wavelength-routed optical networks},
  booktitle = {Optical Fiber Communication Conference, 1999, and the International Conference on Integrated Optics and Optical Fiber Communication. OFC/IOOC '99. Technical Digest},
  year = {1999},
  volume = {1},
  pages = {59--61 vol.1},
  url = {http://dx.doi.org/10.1109/OFC.1999.767791},
  doi = {http://dx.doi.org/10.1109/OFC.1999.767791}
}
Ramamurthy, B., Iness, J. & Mukherjee, B. (1998), "Optimizing amplifier placements in a multiwavelength optical LAN/MAN: the equally powered-wavelengths case", IEEE/OSA Journal of Lightwave Technology., In IEEE/OSA Journal of Lightwave Technology. Vol. 16(9), pp. 1560-1569.
Abstract: Wavelength division multiplexing (WDM) provides the ability to utilize the enormous bandwidth offered by optical networks, using today's electronics. WDM-based optical networks employing passive-star couplers have been proposed for deployment in local and metropolitan areas. Optical amplification is often required in such networks to compensate for the signal attenuation along the fiber links and the splitting and coupling losses in the network. However, an optical amplifier has constraints on the maximum gain and the maximum output power it can supply; thus optical amplifier placement becomes a challenging problem. A simplifying assumption for analytical tractability requires that all wavelengths, present at a particular point in a fiber, be at the same power level, viz, the equally powered-wavelengths case. However, previous studies did not minimize the total number of amplifiers while achieving power equalization. In this paper, we formulate the minimization of amplifiers with power equalization as a mixed integer linear program (MILP) that can be solved by a linear program solver. Illustrative examples on sample networks are presented, which demonstrate the characteristics and the advantages of our optimal amplifier placement algorithm
BibTeX:
@article{RaIM98jlt,
  author = {Ramamurthy, B. and Iness, J. and Mukherjee, B.},
  title = {Optimizing amplifier placements in a multiwavelength optical LAN/MAN: the equally powered-wavelengths case},
  booktitle = {IEEE/OSA Journal of Lightwave Technology},
  journal = {IEEE/OSA Journal of Lightwave Technology},
  year = {1998},
  volume = {16},
  number = {9},
  pages = {1560--1569},
  url = {http://dx.doi.org/10.1109/50.712237},
  doi = {http://dx.doi.org/10.1109/50.712237}
}
Ramamurthy, B., Iness, J. & Mukherjee, B. (1998), "Optimizing amplifier placements in a multiwavelength optical LAN/MAN: the unequally powered wavelengths case", IEEE/ACM Transactions on Networking., In Networking, IEEE/ACM Transactions on. Vol. 6(6), pp. 755-767.
Abstract: Optical networks based on passive-star couplers and employing WDM have been proposed for deployment in local and metropolitan areas. These networks suffer from splitting, coupling, and attenuation losses. Since there is an upper bound on transmitter power and a lower bound on receiver sensitivity, optical amplifiers are usually required to compensate for the power losses mentioned above. Due to the high cost of amplifiers, it is desirable to minimize their total number in the network. However, an optical amplifier has constraints on the maximum gain and the maximum output power it can supply; thus, optical amplifier placement becomes a challenging problem. In fact, the general problem of minimizing the total amplifier count is a mixed-integer nonlinear problem. Previous studies have attacked the amplifier-placement problem by adding the “artificial” constraint that all wavelengths, which are present at a particular point in a fiber, be at the same power level. This constraint simplifies the problem into a solvable mixed-integer linear program. Unfortunately, this artificial constraint can miss feasible solutions that have a lower amplifier count but do not have the equally powered wavelengths constraint. In this paper, we present a method to solve the minimum-amplifier-placement problem, while avoiding the equally powered wavelength constraint. We demonstrate that, by allowing signals to operate at different power levels, our method can reduce the number of amplifiers required
BibTeX:
@article{RaIM98ton,
  author = {Ramamurthy, B. and Iness, J. and Mukherjee, B.},
  title = {Optimizing amplifier placements in a multiwavelength optical LAN/MAN: the unequally powered wavelengths case},
  booktitle = {Networking, IEEE/ACM Transactions on},
  journal = {IEEE/ACM Transactions on Networking},
  year = {1998},
  volume = {6},
  number = {6},
  pages = {755--767},
  url = {http://dx.doi.org/10.1109/90.748087},
  doi = {http://dx.doi.org/10.1109/90.748087}
}
Ramamurthy, B. & Mukherjee, B. (1998), "Wavelength conversion in WDM networking", IEEE Journal on Selected Areas in Communications., In Selected Areas in Communications (JSAC), IEEE Journal on. Vol. 16(7), pp. 1061-1073.
Abstract: Wavelength conversion has been proposed for use in wavelength-division multiplexed networks to improve efficiency. This study highlights systems challenges and performance issues which need to be addressed in order to incorporate wavelength conversion effectively. A review/survey of the enabling technologies, design methods, and analytical models used in wavelength-convertible networks is provided
BibTeX:
@article{RaMu96jsac,
  author = {Ramamurthy, B. and Mukherjee, B.},
  title = {Wavelength conversion in WDM networking},
  booktitle = {Selected Areas in Communications (JSAC), IEEE Journal on},
  journal = {IEEE Journal on Selected Areas in Communications},
  year = {1998},
  volume = {16},
  number = {7},
  pages = {1061--1073},
  url = {http://dx.doi.org/10.1109/49.725178},
  doi = {http://dx.doi.org/10.1109/49.725178}
}
Datta, D., Ramamurthy, B., Feng, H., Heritage, J.P. & Mukherjee, B. (1998), "BER-based call admission in wavelength-routed optical networks", In Optical Fiber Communication Conference. February 1998. Volume 2, pp. 1-3. Optical Society of America.
BibTeX:
@inproceedings{Datt98ofc,
  author = {Datta, Debasish and Ramamurthy, Byrav and Feng, Helena and Heritage, Jonathan P. and Mukherjee, Biswanath},
  title = {BER-based call admission in wavelength-routed optical networks},
  booktitle = {Optical Fiber Communication Conference},
  publisher = {Optical Society of America},
  year = {1998},
  volume = {2},
  pages = {1--3},
  url = {http://www.opticsinfobase.org/abstract.cfm?id=94350},
  doi = {http://dx.doi.org/10.1109/OFC.1998.657234}
}
Datta, D., Feng, H., Ramamurthy, B., Heritage, J.P. & Mukherjee, B. (1998), "BER-based call admission in wavelength-routed optical networks", OSA Trends in Optics and Photonics: Optical Networks and Their Applications., January, 1998. Vol. 20, pp. 1-3. Optical Society of America.
BibTeX:
@article{Datt98tops,
  author = {Datta, Debasish and Feng, Helena and Ramamurthy, Byrav and Heritage, Jonathan P. and Mukherjee, Biswanath},
  title = {BER-based call admission in wavelength-routed optical networks},
  journal = {OSA Trends in Optics and Photonics: Optical Networks and Their Applications},
  publisher = {Optical Society of America},
  year = {1998},
  volume = {20},
  pages = {1--3},
  url = {http://www.opticsinfobase.org/abstract.cfm?id=115998}
}
Ramamurthy, B., Iness, J. & Mukherjee, B. (1997), "Minimizing the number of optical amplifiers needed to support a multi-wavelength optical LAN/MAN", In INFOCOM '97. The 16th Conference on Computer Communications. Volume 1, pp. 261-268.
Abstract: Optical networks based on passive star couplers and employing wavelength-division multiplexing (WDM) have been proposed for deployment in local and metropolitan areas. Amplifiers are required in such networks to compensate for the power losses due to splitting and attenuation. However, an optical amplifier has constraints on the maximum gain and the maximum output power it can supply; thus optical amplifier placement becomes a challenging problem. The general problem of minimizing the total amplifier count, subject to the device constraints, is a mixed-integer nonlinear problem. Previous studies have attacked the amplifier-placement problem by adding the “artificial” constraint that all wavelengths, which are present at a particular point in a fiber, be at the same power level. In this paper, we present a method to solve the minimum-amplifier-placement problem while avoiding the equally-powered-wavelength constraint. We demonstrate-that, by allowing signals to operate at different power levels, our method can reduce the number of amplifiers required in several small to medium-sized networks
BibTeX:
@inproceedings{RaIM97infocom,
  author = {Ramamurthy, B. and Iness, J. and Mukherjee, B.},
  title = {Minimizing the number of optical amplifiers needed to support a multi-wavelength optical LAN/MAN},
  booktitle = {INFOCOM '97. The 16th Conference on Computer Communications},
  journal = {INFOCOM '97. The 16th Conference on Computer Communications},
  year = {1997},
  volume = {1},
  pages = {261--268},
  url = {http://dx.doi.org/10.1109/INFCOM.1997.635138},
  doi = {http://dx.doi.org/10.1109/INFCOM.1997.635138}
}
Borella, M.S., Jue, J.P., Banerjee, D., Ramamurthy, B. & Mukherjee, B. (1997), "Optical components for WDM lightwave networks", Proceedings of the IEEE., In Proceedings of the IEEE. Vol. 85(8), pp. 1274-1307.
Abstract: Recently, there has been growing interest in developing optical fiber networks to support the increasing bandwidth demands of multimedia applications, such as video conferencing and World Wide Web browsing. One technique for accessing the huge bandwidth available in an optical fiber is wavelength-division multiplexing (WDM). Under WDM, the optical fiber bandwidth is divided into a number of nonoverlapping wavelength bands, each of which may be accessed at peak electronic rates by an end user. By utilizing WDM in optical networks, we can achieve link capacities on the order of 50 THz. The success of WDM networks depends heavily on the available optical device technology. This paper is intended as a tutorial on some of the optical device issues in WDM networks. It discusses the basic principles of optical transmission in fiber and reviews the current state of the art in optical device technology. It introduces some of the basic components in WDM networks, discusses various implementations of these components, and provides insights into their capabilities and limitations. Then, this paper demonstrates how various optical components can be incorporated into WDM optical networks for both local and wide-area applications. Finally, the paper provides a brief review of experimental WDM networks that have been implemented
BibTeX:
@article{Bore97proc,
  author = {Borella, M. S. and Jue, J. P. and Banerjee, D. and Ramamurthy, B. and Mukherjee, B.},
  title = {Optical components for WDM lightwave networks},
  booktitle = {Proceedings of the IEEE},
  journal = {Proceedings of the IEEE},
  year = {1997},
  volume = {85},
  number = {8},
  pages = {1274--1307},
  url = {http://dx.doi.org/10.1109/5.622506},
  doi = {http://dx.doi.org/10.1109/5.622506}
}
Iness, J., Ramamurthy, B., Mukherjee, B. & Bala, K. (1996), "Elimination of all-optical cycles in wavelength-routed optical networks", IEEE/OSA Journal of Lightwave Technology., In IEEE/OSA Journal of Lightwave Technology. Vol. 14(6), pp. 1207-1217.
Abstract: A transparent (wide-area) wavelength-routed optical network may be constructed by using wavelength cross-connect switches connected together by fiber to form an arbitrary mesh structure. The network is accessed through electronic stations that are attached to some of these cross-connects. These wavelength cross-connect switches have the property that they may configure themselves into unspecified states. Each input port of a switch is always connected to some output port of the switch whether or not such a connection Is required for the purpose of information transfer. Due to the presence of these unspecified states, there exists the possibility of setting up unintended all-optical cycles in the network (viz., a loop with no terminating electronics in it). If such a cycle contains amplifiers [e.g., erbium-doped fiber amplifiers (EDFA's)], there exists the possibility that the net loop gain is greater than the net loop loss. The amplified spontaneous emission (ASE) noise from amplifiers can build up in such a feedback loop to saturate the amplifiers and result in oscillations of the ASE noise in the loop. Such all-optical cycles as defined above (and hereafter referred to as “white” cycles) must be eliminated from an optical network in order for the network to perform any useful operation. Furthermore, for the realistic case in which the wavelength cross-connects result in signal crosstalk, there is a possibility of having closed cycles with oscillating crosstalk signals. We examine algorithms that set up new transparent optical connections upon request while avoiding the creation of such cycles in the network. These algorithms attempt to find a route for a connection and then (in a post-processing fashion) configure switches such that white cycles that might get created would automatically get eliminated. In addition, our call-set-up algorithms can avoid the possibility of crosstalk cycles
BibTeX:
@article{IRMB96,
  author = {Iness, J. and Ramamurthy, B. and Mukherjee, B. and Bala, K.},
  title = {Elimination of all-optical cycles in wavelength-routed optical networks},
  booktitle = {IEEE/OSA Journal of Lightwave Technology},
  journal = {IEEE/OSA Journal of Lightwave Technology},
  year = {1996},
  volume = {14},
  number = {6},
  pages = {1207--1217},
  note = {(Jointly published by the IEEE Journal on Selected Areas in Communications (JSAC).)},
  url = {http://dx.doi.org/10.1109/50.511622},
  doi = {http://dx.doi.org/10.1109/50.511622}
}