Path control apparatus, path control method, path control program, and network system

摘要

A path control apparatus of the present invention includes: a status change detecting unit that detects a status change of a network; a path calculating unit that decides a path in accordance with the status of the network; and a calculation execution node deciding unit that compares a shortest path tree, which is established before occurrence of a change in the status of the network calculated by the path calculating unit, with a shortest path tree, which is established after the occurrence of the change in the status of the network calculated by the path calculating unit, and creates information required for determining whether a node apparatus in the network needs a path update, when the change occurs in the status of the network.

主权项

1. A path control apparatus comprising:
a status change detecting unit implemented at least in hardware and that detects a status change of a network; a path calculating unit implemented at least in hardware and that decides a path in accordance with the status of the network; a calculation execution node deciding unit implemented at least in hardware, the calculation execution node deciding unit selecting a first node connected to a next forwarding destination via a failure link in a path table before an occurrence of the status change, the calculation execution node selecting a second node in a path from the path control apparatus to the first node in a first shortest path tree, the calculation execution node deciding unit deciding that the second node is a node apparatus in the network which needs a path update, when the calculation execution node deciding unit determines that a second value is smaller than or equal to a first value, the first value being obtained by subtracting a cost for a path from the path control apparatus to the first node in a second shortest path tree, from a cost for a path from the path control apparatus to the first node in the first shortest path tree, the second value being a total of a cost for a path from the path control apparatus to the second node in the second shortest path tree and a cost for a path from the second node to the path control apparatus in a third shortest path tree, the first shortest path tree being a shortest path tree after the occurrence of the status change, the second shortest path tree being a shortest path tree before the occurrence of the status change, the third shortest path tree being a shortest path tree in an opposite direction before the occurrence of the status change; a message creating unit implemented at least in hardware and that creates a message showing the decided node apparatus which needs a path update; and a message transmitting unit implemented at least in hardware and that transmits the message to the decided node apparatus which needs a path update.