Label switched path set up scheme with reduced need for label set up retry operation

摘要

A label switched path set up scheme which is capable of detecting a loop of the label switched path efficiently and quickly, and which can enable the switching of the label switched path even in the case where conventionally a label switch path loop would be erroneously detected at a time of the route change, without requiring a label set up retry operation from a previous hop node device of the node device that have erroneously detected the loop which would have been necessary conventionally. A label switched path set up request message is transferred up to a node that can confirm that the path does not form a loop, while each node through which the message passes stores the fact that it is in a message processing state. Then, in a process where a response message is returned from that node, the message processing state of each node on the route of the path is released sequentially, and this releasing establishes the path set up.