Patent ID: 7512120

Claim:
A node in a packet communication system comprised of nodes and links, said node being a destination node as a destination of a packet transmitted from a correspondent node, said node comprising: an advertisement receiver configured to receive an advertisement of path information, when a path from the correspondent node to the destination node has been updated, about a path from the correspondent node to the destination node after the path has been updated; a Path MTU discovery execution determining unit configured to compare path information of the path before the path has been updated and path information of the path after the path has been updated and determine whether a discovery of a Path MTU of the path from the correspondent node to the destination node should be executed; a Path MTU setting unit configured to set a Path MTU of the path after the path has been updated on the basis of the path information of the path after the path has been updated which was received by the advertisement receiver, when the Path MTU discovery execution determining unit determines that the discovery of the Path MTU should be executed; and a Path MTU announcer configured to announce to the correspondent node the Path MTU of the path after the path has been updated which was set by the Path MTU setting unit when the Path MTU discovery execution determining unit determines that the discovery of the Path MTU should be executed.