Patent ID: 6529958
Filing Date: 2003-03-04
Classification: H04L

Abstract:
A method for setting up a label switched path, comprising the steps of:judging whether the label switched path forms a loop or not at a node that received a request message regarding a set up of the label switched path for a packet flow, on a basis of label switched path information stored in a first mode at said node that received the request message, the request message including a flow identifier for identifying the packet flow and information indicating that it is a message currently awaiting a response regarding the packet flow, and the first mode indicating that a message from which the label switched path information originates is a message currently awaiting a response; storing the flow identifier contained in the request message as the label switched path information in the first mode at said node that received the request message, and transferring the request message from said node that received the request message to another node on a route of the packet flow, when said node that received the request message cannot judge that the label switched path does not form a loop; returning a response message for the request message from said node that received the request message when said node that received the request message judges that the label switched path does not form a loop; and changing the label switched path information currently stored in the first mode at a node that received the response message into a second mode different from the first mode such that the label switched path information that is changed into the second mode will not be used subsequently in judging whether any requested label switched path forms a loop or not at said node that received the response message and the label switched path will become available at said node that received the response message.