Patent ID: 7536101

Claim:
A communication system comprising: a first communication device and a second communication device; a first optical switch and a second optical switch; a first link coupling the first communication device to the first optical switch, and a second link coupling the second communication device to the second optical switch; a third link coupling the first optical switch to the second optical switch, wherein during normal operation, the first optical switch connects the first link to the third link and the second optical switch connects the third link to the second link; a plurality of back-up links coupling the first optical switch to the second optical switch, wherein the back-up links have various monetary costs and latencies; and in response to a fault on the third link, the first optical switch and the second optical switch are configured to automatically select an available one of the back-up links having a lowest monetary operating cost and an acceptable latency, and in response to the selection, to automatically disconnect the first link and the second link from the third link and automatically connect the first link and the second link to the selected back-up link; wherein the first communication device is configured to provide Open Systems Interconnect (OSI) layer 2/3 protection in response to a carrier delay timer time-out, wherein the carrier delay timer is set based on a time period that allows the first optical switch and the second optical switch to detect the fault and implement the selected back-up link; and wherein the time period comprises a detection time period to detect the fault, a switch time period to select the selected back-up link, and a restoration time period for a signal to propagate over the selected back-up link.