Survivable Multipath Traffic Grooming in Telecom Mesh Networks With Inverse Multiplexing

We investigate the survivable traffic grooming problem with inverse multiplexing in telecommunication mesh networks employing next-generation SONET/SDH and WDM. With the support of virtual concatenation, a connection of any bandwidth can be provisioned as several subconnections (i.e., inverse multiplexed) over diverse paths. Therefore, it is important to efficiently groom and protect these low-speed subconnections onto high-capacity wavelength channels, considering the typical constraints. We propose and investigate the characteristics of survivable multipath traffic grooming with protection-at-connection and protection-at-lightpath levels for grooming connections with shared protection, subject to the constraints of the inverse-multiplexing factor, differential-delay constraint, and grooming ports. Since this problem is NP-complete, we propose effective heuristics using a novel analytical model. Our results show that (1) the network performance, in metrics of bandwidth blocking ratio and resource overbuild, can be notably improved by exploiting the inverse-multiplexing capability, (2) tight constraints have negative impact on performance, (3) protection-at-connection performs better in most cases of multipath provisioning when the constraints are not too tight, and (4) protection-at-lightpath achieves better performance when the number of grooming ports is moderate or small.