Lightpath restoration in WDM optical networks

Optical networks employing wavelength-division multiplexing and wavelength routing are potential candidates for future wide area networks. Because the se networks are prone to component Failures and carry a large volume of tra ffic, maintaining a high level of service availability is on important issu e. This article discusses providing fault tolerance capability to the optic al layer in WDM-based transport networks. It presents a survey on restorati on schemes available in the literature, explains the operation of these sch emes, and discusses their performance.