WDM loop-back recovery in mesh networks

Current means of providing loop-back recovery, which is widely used in SONET, relies on fiber-based recovery, where a fiber is used to back up another fiber. We present WDM-based loop-back recovery for optical networks where wavelengths are used to back up other wavelengths. We present two new algorithms for performing WDM-based loop-back over optical mesh networks. The first algorithm performs recovery for link failures. We compare its operation with known ways of providing loop-back recovery and show that the known methods are not applicable to WDM-based recovery. The second algorithm performs WDM loop-back recovery for node failures. We illustrate the operation of both algorithms and prove their validity. We discuss the advantages of WDM-based loop-back for flexibility in WDM service provisioning