Patent ID: 7466649

Claim:
A method for setting a value of waiting time for switching, the method comprising: at a node in a sonet ring: determining which path to the node is an actual path and which path is a preliminary path; determining whether a one way fiber transmission delay of the actual path is less than a one way fiber transmission delay of the preliminary path; if the one way fiber transmission delay of the actual path is greater than the one way fiber transmission delay of the preliminary path, setting a switching time to zero and performing normal switching; if the one way fiber transmission delay of the actual path is less than the one way fiber transmission delay of the preliminary path: setting a switching time equal to the one way fiber transmission delay of the preliminary path minus the one way fiber transmission delay of the actual path; determining whether a path alarm indication signal (AIS) occurred in the actual path; if the path alarm indication signal (AIS) occurred in the actual path: stopping path switching of the actual path within the switching time; determining whether a path alarm indication signal occurred in the preliminary path; if the path alarm indication signal did not occur in the preliminary path, performing normal path switching for the actual path.