Survivable Multipath Provisioning with Differential Delay Constraint in Telecom Mesh Networks

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 which should not be ignored. We investigate survivability of service paths based on differential-delay constraint (DDC) and multipath provisioning together in a telecom backbone mesh network. We present a DDC-based K link-disjoint paths algorithm (DDCKDP) for multipath provisioning subject to DDC. We also compare it with the minimum-cost-flow (MCF) and K shortest link-disjoint paths (KDP) algorithm, using Shared Protection of the Largest Individual Traversed link (SPLIT), under dynamic service request with several different DDCs. We find that (1) exploiting link-disjoint paths is very efficient for survivable multipath provisioning; and (2) SPLIT-DDCKDP is resource efficient, has low signaling overhead, and has fast fault-recovery for survivable multipath provisioning with DDC. For a 5 ms DDC, DDCKDP can decrease the Bandwidth Blocking Ratio (BBR) by more than 100% compared with KDP in a typical US backbone network.