Technique for graceful shutdown of a routing protocol in a network
AssigneeCisco Technology, Inc.
InventorsJohn Galen Scudder, Muthurajah Sivabalan, David D. Ward
Life of this patent
Estimating the term…
Abstract
In one embodiment, a router generates a notification message that indicates the router is to be gracefully removed from service. The router sends the notification message to peers of the router in a network. The router then continues to forward packets for a grace period after sending the notification message, to permit backup paths to be propagated to peers, and to be put into service, prior to withdrawal from service of paths through the router. Thereafter, the router is removed from service at the expiration of the grace period.
Claims18
A method comprising:
- generating a notification message that indicates that a router is to be gracefully removed from service and that one or more best paths through the router are to be treated as paths of last resort from receipt of the notification message until the router is removed from service;
- sending the notification message to peers of the router in a network to trigger the peers to announce backup paths and to place one or more of the backup paths into service to replace the one or more best paths;
- continuing to forward packets from the router for a grace period after sending the notification message, to permit the announced backup paths to be propagated among peers, and to be placed into service, prior to withdrawal from service of the best paths through the router;
- and
- removing the router from service at the expiration of the grace period.
A method comprising:
- receiving a notification message that indicates a router is to be gracefully removed from service, the notification message indicating that the router will continue to forward packets for a grace period before withdrawing paths through the router from service;
- in response to receiving the notification message, marking a best path through the router that is to be withdrawn from service as a last resort path;
- attempting to select a path that does not pass through the router as the best path;
- continuing to utilize the last resort path through the router that is to be withdrawn from service until the path that does not pass through the router is selected as the best path or the grace period has elapsed;
- and
- in response to the path that does not pass through the router being selected as the best path or the grace period elapsing, ceasing to utilize the last resort path through the router.
An apparatus comprising:
- a processor;
- a routing protocol module executed by the processor, the routing protocol module operable to generate a notification message that indicates that the apparatus is to be gracefully removed from service at the expiration of a grace period and that one or more best paths through the apparatus are to be treated as paths of last resort from receipt of the notification message until the apparatus is removed from service;
- and
- a network interface operable to send the notification message to peers of the apparatus in a network to trigger the peers to announce backup paths and to place one or more of the backup paths into service to replace the one or more best paths,
- wherein the apparatus is operable to continue to forward packets for the grace period after the notification message is sent, to permit the announced backup paths to be propagated among peers, and to be placed into service, prior to withdrawal from service of the best paths through the apparatus.
Dependencies are inferred from the claim text.