Protection switching in communication networks

In this paper, we survey different approaches to achieve survivability in communication networks. Due to volume and throughput of data on optical networks, and catastrophic consequences of failures in those networks, we focus on survivability in optical Wavelength Division Multiplexing (WDM) networks. However, some of the techniques studied here are used in other types of networks as well. We will review the trade offs between protection switching versus dynamic restoration; and survivability in electronic layer versus optical layer. We go over link protection and path protection methodologies. We cover protection of mesh networks using p-cycles. Cross-layer design for survivability is considered; and problem of lightpath embedding is reviewed. Failure of a single link in the physical topology will not propagate to higher-level logical network, when we use such approaches. We tackle the problem of survivability in Shared Risk Link Groups (SRLGs) and Probabilistic SRLGs in face multiple network failures.