BGP - Graceful Restart Mechanism
The BGP Graceful Restart Mechanism is used when a BGP router or its peer needs to be restarted, typically for software upgrades or any other maintenance activity. The BGP session is preserved during the restart, and the forwarding plane continues to work as before. It's a way to minimize network disruptions during planned outages. After the restart, the BGP router relearns the routes from its peers. The mechanism helps in the situation where a BGP speaker is temporarily out of service. The neighboring routers are informed about the restart, and they keep the routing information unchanged for the restarting router for a certain period.
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