Differentiated Quality-of-Recovery in Survivable Optical Mesh Networks Using $p$-Structures

Abstract

This paper investigates design methods of protection schemes in survivable WDM networks that use preconfigured protection structures ( $p$ -structures) in order to provide different quality-of-recovery (QoR) classes within 100% resilient single-link protection schemes. QoR differentiation is a practical and effective approach in order to strike different balances among protection cost, recovery delay, and management complexity. Based on the degree of pre-cross connectivity of the protection structures, we develop three design approaches of shared protection capacity schemes based on the following: 1) fully pre-cross-connected $p$ -structures ( $fp$ -structures); 2) partially pre-cross-connected $p$ -structures ( $pp$ -structures); and 3) dynamically reconfigured $p$ -structures ( $dp$ -structures). In order to identify the optimal combinations of protection structures to meet the requirements of the three QoR classes, we use a column generation (CG) model that we solve using large-scale optimization techniques. Our CG decomposition approach is based on the separation processes of the design and selection of the protection structures. In the design process of the protection structures, the shape and protection capability of each $p$ -structure is decided dynamically during the selection process depending on the network topology and the targeted QoR parameters. Extensive experiments are carried out on several data instances with different design constraints in order to measure the protection capacity cost and the recovery delay for the three QoR classes.