Patent ID: 7272307

Claim:
A multi-node optical network comprising: a plurality of spaced apart nodes; a plurality of working communication paths, the members of the plurality extend between and carry traffic in a selected direction between selected nodes; a normally unused predetermined protection communication path that extends between all of the nodes forming a closed ring, the protection path is available to carry traffic in the selected direction, as needed at least between pairs of nodes in response to a failure of any one of the working paths between a respective pair of nodes; substantially identical activation circuitry at each node, the activation circuitry at each node of a selected pair of nodes detects a signal loss indicative of the failure of one of the working paths therebetween, each activation circuitry communicates with the other via the protection path to place that portion of the protection path between the selected pair of nodes into service in response to failure of any one of the working paths therebetween where the activation circuitry at a receiving node of the selected pair of nodes, in response to a loss of light on a working path from the transmitting node of the selected pair of nodes, terminates transmission on the respective working path and initiates a first dataless transmission via the protection path to the transmitting node, where the activation circuitry at the transmitting node, in response to a loss of light on the working path from the receiving node, terminates transmission on the respective working path and initiates a second dataless transmission, via the protection path, to the receiving node, the activation circuitry switches at least the second dataless transmission to traffic carrying between the nodes, and where the remaining members of the plurality of working paths continue to carry traffic in the selected direction.