Optimal dedicated protection approach to shared risk link group failures using network coding

摘要

Survivable routing serves as a key role in connection-oriented communication networks for achieving desired service availability for each connection. This is particularly critical for the success of all-optical mesh networks where each lightpath carries a huge amount of data. Currently, 1+1 dedicated path protection appears to be the most widely deployed network resilience mechanism because it offers instantaneous recovery from network failures. However, 1+1 protection consumes almost twice as much capacity as required, which imposes a stringent constraint on network resource utilization. In addition, finding an SRLG-disjoint path is essential for 1+1 protection, which is nonetheless subject to non-trivial computation complexity and may fail in some SRLG scenarios. To address these problems, we introduce a novel framework of 1+1 protection, called Generalized Dedicated Protection (GDP), for achieving instantaneous recovery from any SRLG failure event. It is demonstrated, that finding a non-bifurcated optimal solution for GDP is NP-complete. Thus, the paper presents a novel scheme applying Generalized Dedicated Protection and Network Coding (GDP-NC) to ensure both optimal resource utilization among dedicated protection approaches and instantaneous recovery for single unicast flows, which can be split into multiple parts in all-optical networks. We demonstrate that the proposed GDP-NC survivable routing problem is polynomial-time solvable, owing to the ability to bifurcate flows. This flexibility comes at the expense of additional hardware for linear combination operations for the optical flows.