Patent ID: 7113699

Claim:
A method of propagating fault information in an optical network, comprising: detecting a fault associated with a signal received by a node; responsive to determining that the node is configured with a service capable of forwarding an alarm signal for the fault, forwarding the alarm signal; responsive to determining that the node is configured with a service incapable of generating an alarm signal for the fault, turning off a laser transmitter associated with propagating the signal towards its destination; and wherein the node is one of a source node, a destination node, and an intervening node along an optical add-drop path between the source node and the destination node, wherein, in the source node case, the fault is detected at a tributary interface of the node, and the laser transmitter is a line-side laser transmitter for propagating the signal to another node, wherein, in the destination node case, the fault is detected at a line interface of the node, and the laser transmitter is a tributary-side laser transmitter for propagating the signal to a tributary network, and wherein, in the intervening node case, the fault is detected at a line interface of the node and the laser transmitter is a line-side laser transmitter for propagating the signal to a subsequent node along the optical add-drop path.