A novel recursive shared segment protection algorithm in survivable WDM networks

This paper investigates the problem of dynamic survivable routing for shared segment protection in mesh Wavelength-Division-Multiplexing (WDM) optical networks. We propose a heuristic algorithm, named Recursive Shared Segment Protection (RSSP), to introduce a more flexible way to partition the working path into segments and compute the corresponding backup segments. In RSSP, the working segments cannot be determined before the backup segments are found, we adopt a recursive process to compute the backup segments one by one and then choose an optimized way to partition the working path. The calculations of every neighbor working segment and its backup segment are connected with each other. We constrain the hop count for each backup segment to insure the short failure recovery time and control the bandwidth resource utilization. Compared with the Share Path Protection (SPP), RSSP can achieve much shorter failure recovery time with a little sacrifice in bandwidth resource utilization and RSSP can also perform better compromise between the failure recovery time and the bandwidth resource utilization than the Equal-Length Segment Protection (ELSP) algorithm. We evaluate the effectiveness of RSSP and the results are found to be promising.