| 摘要 |
A change-back system is designed for an asynchronous transfer mode network in which a rerouting path is set to replace an original path when a fault is generated in the original path within the network, which network includes a plurality of communication nodes (21-23) which are coupled via lines and communicate information in the form of cells, and the original path and the rerouting path couple first and second communication nodes within the network. The change-back system makes a change-back process to change the path used from the rerouting path to the original path when the fault is restored. The change-back system includes a first circuit (32) for detecting a restoration of a fault in the original path, a second circuit (33) for transmitting a cell from the first communication node to the second communication node via each of the rerouting path and the original path when the restoration of the fault is detected, prior to making the change-back process, and for measuring a first time it takes for the cell to travel through the rerouting path and a second time it takes for the cell to travel through the original path, and a third circuit (31, 34) for calculating a guard time which is a difference between the first and second times and for delaying transmission of a cell from the second circuit to the original path after the restoration of the fault, so that the cell after the restoration of the fault is transmitted to the original path at least after a time which corresponds to the difference from a time when a cell is last transmitted to the rerouting path immediately before the fault is restored. <IMAGE> |
