Survivable Multipath Provisioning with Differential Delay Constraint in Telecom Mesh Networks

Survivability is a critical concern in modern telecom mesh networks because the failure of a network element may cause tremendous data and revenue loss in such networks using high-capacity optical fibers employing wavelength-division multiplexing (WDM). Multipath provisioning is a key feature of next-generation SONET/SDH networks (which can be used on top of optical WDM), and they can support virtual concatenation (VCAT); thus, multipath provisioning can significantly outperform single-path provisioning in resource efficiency, service resilience, and flexibility. However, in multipath provisioning, differential delay is an important constraint that should be considered. We investigate survivability of service paths based on differential-delay constraint (DDC) and multipath provisioning together in telecom backbone mesh networks. We propose the Shared Protection of the Largest Individual Traversed link (SPLIT) method for survivable multipath provisioning and present a DDC-based algorithm for multipath routing subject to DDC. We also compare the DDC-based algorithm with the K shortest link-disjoint paths (KDP) algorithm, using SPLIT, under dynamic service requests. We find that exploiting link-disjoint paths is very efficient for survivable multipath provisioning, and our algorithm is resource-efficient, has low signaling overhead, and has fast fault recovery for survivable multipath provisioning with DDC. For a 5-ms DDC, our algorithm can decrease the bandwidth blocking ratio (BBR) significantly in typical U.S. backbone networks.