RIP timers

The RIP routing protocol has the following timers:

  • Update - every 30 seconds, an update with the entire RIP routing table is sent to all other RIP routers.
  • Invalid - 180 seconds, the amount of time after which a route is considered unreachable. After the timer expires the hop count of the routing entry will be set to 16, marking the destination as unreachable.
  • Hold-down - 180 seconds, the amount of time during which information about other paths is ignored. The hold-down timer is started per route entry when the hop count for a particular route has changed from a lower value to a higher value. This allows the route to get stabilized. During this time no update can be done to that routing entry. This is not part of the RFC 1058 but is a Cisco implementation.
  • Flush - 240 seconds, is the time between when the route is marked as unreachable and the removal of the entry from the routing table. By default, the value is 60 seconds longer than the Invalid timer. So for 60 seconds, the router will be advertising a route with a hop count of 16 (unreachable) before it is removed.

These values are the same for RIPv1, RIPv2, and RIPng

https://tools.ietf.org/html/rfc1058 https://datatracker.ietf.org/doc/html/rfc2453 https://datatracker.ietf.org/doc/html/rfc2080

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