Abstract: A facility is provided to allow a supervisory message to quickly propagate through a transmission network without delay. Specifically, a supervisory message is quickly routed from one node to a next node by (a) splitting the control channel signal carrying the supervisory message at a receiving node, (b) sending one of the split control channel signals to an output via switchable apparatus for immediate transmission the next node and (c) sending the other split signal to a controller for analysis. If the controller invokes a predetermined procedure as a result of the content of the message, e.g., invokes protection switching, then the controller forms a supervisory message identifying the invoked procedure, operates the switchable apparatus so that the message identifying the invoked procedure may be routed to the output in place of the split channel signal message.

Abstract: An optical transmission system formed from a plurality of nodes interconnected in a ring configuration via at least two transmission media provides protection capacity for each optical channel. If a channel signal does not meet predetermined criteria, then a loss of signal indication is declared for the channel and one of a plurality of protection switching states is invoked to re-route service traffic carried by the impaired channel to its destination via corresponding protection capacity. The switching states include particular transmission states and at least “keep-alive” and “protection access” states.

Abstract: An optical communications system employs a plurality of optical nodes interconnected in a ring configuration by at least two optical transmission media, for example, optical fiber. The at least two optical transmission media, in this example, provide optical service transmission capacity and optical protection transmission capacity. Efficient restoration of optical communications between optical nodes in the ring, after an optical transmission media failure, is realized by employing a relatively simple and efficient optical switch matrix having a first number of possible switching states and, then, by utilizing only a second number of the switching states fewer than the first number to switch optically from the optical service transmission capacity of the failed or faulted optical transmission media to the optical protection transmission capacity of another optical transmission media.

Abstract: An optical communications system employs a plurality of optical nodes interconnected in a ring configuration by at least two optical transmission media, for example, optical fiber. The at least two optical transmission media, in this example, provide optical service transmission capacity and optical protection transmission capacity. Efficient restoration of optical communications between optical nodes in the ring, after an optical transmission media failure, is realized by employing a relatively simple and efficient optical switch matrix having a first number of possible switching states and, then, by utilizing only a second number of the switching states fewer than the first number to switch optically from the optical service transmission capacity of the failed or faulted optical transmission media to the optical protection transmission capacity of another optical transmission media.

Abstract: An optical communications system employs a plurality of optical nodes interconnected in an optical ring transmission configuration by at least two optical transmission media, for example, optical fiber. The at least two optical transmission media, in this example, provide optical service transmission capacity and optical protection transmission capacity. Efficient restoration of optical communications between optical nodes in the optical ring transmission configuration, after an optical transmission media failure, is realized by employing an autonomous optical restoration arrangement and technique. To this end, each node autonomously controls an optical switch matrix in the node in effecting the desired restoration without the need of switch control signals transmitted from any other node in the ring, from a main controller or from a central controller.