An improved GMPLS survivability mechanism using link delay-constrained algorithm

It is widely accepted that GMPLS (Generalized MPLS) will be a key technology in the evolution of the next generation of reliable Internet Protocol (IP) backbone networks. Conventional GMPLS-based optical-switching network fault recovery only provides resiliency in terms of path segment selection instead of constraint-based calculation. This can create severe impact on the protocol´s transport plane when a fault occurs to a link or path with many optical connections attached to it. This paper proposes the implementation of an improved GMPLS recovery algorithm based on the metric of optical link delay which is achieved through the pre or post selection of a safer and more stable protection path with fewer connections attached to it, and therefore with a lesser link delay metric compared to other possible paths. The improved recovery algorithm is evaluated using the network simulator ns-2 and more particularly a specialized simulator add-on for GMPLS, called ASONS (Automatically Switched Optical Network Simulator). The results indicate improved resiliency, increased fault avoidance, and reduced packet loss.