Path switching method, communication system, communication device, and program

A communication system comprising:

• a plurality of communication devices, and
• at least one link connecting the communication devices, wherein
• a communication device serving as a relay point of a path includes a resource removal processing unit which, when receiving from an outside request source a removal preparation request specifying a removal target resource existing in the communication device itself, detects a path identifier and a communication device serving as a start point of each path passing through the removal target resource, and for each detected path, transmits a path switching request specifying the detected path identifier of the path and the removal target resource to the communication device serving as the start point of the path, and
• the communication device serving as the start point of the path includes:
• a routing processing unit which, when receiving the path switching request specifying the path identifier and the removal target resource, computes a route of another path having a start point and an end point which are the same as those of the path identified by the path identifier and not passing through the removal target resource, and
• a path switching processing unit which, after performing a setting process of the other path computed by the routing processing unit, performs a disconnecting process of the path identified by the path identifier.

A communication device comprising:

• a resource removal processing unit which, when receiving from an outside request source a removal preparation request specifying a removal target resource existing in the communication device itself, detects a path identifier and a communication device serving as a start point of each path passing through the removal target resource, and for each detected path, transmits a path switching request specifying the detected path identifier of the path and the removal target resource to the communication device serving as the start point of the path;
• a routing processing unit which, when receiving the path switching request specifying the path identifier and the removal target resource, computes a route of another path having a start point and an end point which are the same as those of the path identified by the path identifier and not passing through the removal target resource;
• and
• a path switching processing unit which, after performing a setting process of the other path computed by the routing processing unit, performs a disconnecting process of the path identified by the path identifier.

A computer program product comprising computer implementable instructions to cause a computer to function as:

• a resource removal processing unit which, when receiving from an outside request source a removal preparation request specifying a removal target resource existing in the communication device itself, detects a path identifier and a communication device serving as a start point of each path passing through the removal target resource, and for each detected path, transmits a path switching request specifying the detected path identifier of the path and the removal target resource to the communication device serving as the start point of the path;
• a routing processing unit which, when receiving the path switching request specifying the path identifier and the removal target resource, computes a route of another path having a start point and an end point which are the same as those of the path identified by the path identifier and not passing through the removal target resource;
• and
• a path switching processing unit which, after performing a setting process of the other path computed by the routing processing unit, performs a disconnecting process of the path identified by the path identifier.

A communication device comprising:

• resource removal processing means for, when receiving from an outside request source a removal preparation request specifying a removal target resource existing in the communication device itself, detecting a path identifier and a communication device serving as a start point of each path passing through the removal target resource, and for each detected path, transmitting a path switching request specifying the detected path identifier of the path and the removal target resource to the communication device serving as the start point of the path;
• routing processing means for, when receiving the path switching request specifying the path identifier and the removal target resource, computing a route of another path having a start point and an end point which are the same as those of the path identified by the path identifier and not passing through the removal target resource;
• and
• path switching processing means for, after performing a setting process of the other path computed by the routing processing unit, performing a disconnecting process of the path identified by the path identifier.