A fast lightpath restoration method using two backup paths in WDM networks

WDM networks providing Terabits per second bandwidth are becoming the core technology for the next generation Internet. Due to the tremendous bandwidth offered by these networks, it´s imperative for them to be survivable. Current path-based proactive restoration scheme precomputes a backup lightpath at the time a primary lightpath is setup, thus provides 100% restoration guarantee. Better spare capacity utilization can be achieved using backup multiplexing technique that allows backup lightpaths to share wavelength channels. However, the method has the drawback of long restoration time due to the end-to-end signaling required to setup the backup lightpath upon failure. In this paper, we present a new proactive lightpath restoration method that computes one primary and two backup lightpaths for a traffic demand. Simulation results showed that the new method can significantly reduce the restoration time with only minor increase in capacity requirement.