Multiple-Link Failures Survivability in Optical Networks with Traffic Grooming Capability

This paper investigates the problem of survivable traffic grooming (STG) in shared mesh optical networks and proposes different frameworks for improving the survivability of low speed demands against multiple near simultaneous failures. Capacity reprovisioning has recently been considered for improving the overall network restorability in the event of multiple failures by allocating protection resources after a failure to unprotected and vulnerable connections. In this paper we propose two different reprovisioning schemes (lightpath level reprovisioning, LLR, and connection level reprovisioning, CLR). Each of these schemes is suitable for a different survivable grooming policy. While LLR provides collective reprovisioning of connections at the lightpath level, CLR reprovisions spare bandwidth for lower speed connections instead. We study the performance of these schemes under two grooming policies (PAL and PAC), and we show that while CLR reprovisions substantially more connections than LLR, CLR yields a much better network robustness to near simultaneous failures due to its superior flexibility in using network resources.