Fault Detection and Localization Scheme for All-Optical Overlaid-Star TDM Networks

Fault detection and localization is a crucial issue in all-optical networks. Since most commercially-available all-optical space switches are incapable of detecting the loss of optical signals along the data paths between its input ports and output ports, fault localization becomes a challenge for providing service survivability in such networks. This paper proposes a fault detection and localization scheme for an all-optical overlaid-star TDM network. The proposed scheme employs a fault localization technique that identifies the location of a failure by detecting the power loss of optical signals in data and control channels. Two alternatives are proposed. One requires a control channel on each wavelength of a fiber link while the other requires a small data block to be transmitted in each non-allocated data channel. Based on the proposed fault localization technique, a fault advertisement protocol is further presented, which can be incorporated into the signaling protocol used in the network to facilitate the provisioning of static protection or dynamic restoration. The data loss, fault detection time, and connection recovery time are analyzed for the different failure scenarios.