A system and method for forwarding fault information in an optical network
is disclosed. Responsive to a fault being detected at a node, the fault
information is forwarded to the destination node in the form of a
loss-of-signal condition by turning off laser transmitters used to
propagate the signal towards its destination. Thus, a node or other
network element not capable of generating an alarm signal consistent with
an established alarm signaling protocol, such as a SONET alarm indication
signal (AIS) or an SDH multiplexer section alarm indication signal
MS-AIS, may still forward the fault condition to a downstream element.