On provisioning diverse circuits in heterogeneous multi-layer optical networks

Abstract

Network planners are often requested to provision multiple physically-diverse high-speed circuits over a large carrier’s core (inter-city) DWDM network, which consists of multiple layers and heterogeneous vendor systems. Optimally provisioning such circuits while avoiding shared risk link group (SRLG) failures is an NP-hard problem. In this paper, we propose a novel and practical two-step approach: pre-processing with Integer Linear Programming (ILP) for absolutely or maximally SRLG-diverse routes and post-processing for DWDM system selection, regenerator placement and wavelength assignment. This approach has been implemented in a production network planning tool. According to our experiments, for a typical large carrier’s core optical network, most of the diverse-routing demands can be solved within 1min, even with tens of thousands of binary decision variables, which allows interactive use by network planners.