RIP Redistributed Static Routes Failover

[absuizo14]

If static routes are redistributed into SW1 RIP what will happen if link between sw1 and sw2 fail? what can be done so that if sw1-sw2 link fail sw3 would advertise sa static routes?

[Torbjørn]

S3 will learn and advertise the route towards SW3 from SW1. If the link between SW1 and SW2 fails SW2 should start using the route learned from SW3 as the route towards SW1 is no longer viable.

[Joseph W. Doherty]

Actually, SW3 should ALREADY advertise the routes being redistributed by SW1 to SW2.

Since RIP's best path selection is via least number of hops, if SW1<>SW2 is up, that would be best path to SW4.  If that link is down, SW1<>SW3<>SW2 would become the best path.

[absuizo14]

as i remember RIP only advertises network that are in the "Network x.x.x.x" statement so i dont think SW3 will automatically advertise those static routes between SW1 and SW4 to SW2 although SW3 will be able to learn them.. should i add those static routes to SW3 and redistribute them into its RIP?

[Joseph W. Doherty]

Possibly you're confusing getting a route into a routing protocol and it being distributed by the routing protocol.

[Joseph W. Doherty]

Oh, if my prior reply doesn't make sense, what I'm trying to say is, once a route gets into a routing protocol, it should be available to all routers participating in that routing protocol (excluding specific removals or summarizations, etc.).  In other words, any route placed into the RIP routing protocol, by default, should be available to all the other RIP routers.

For example, assuming on the interconnecting link networks are made know to RIP, the routers without a should know of that network.  I.e., SW1 should know SW2<>SW3, SW2 should know SW1<>SW3, and SW3 should know SW1<>SW2.  Likewise if, SW1 is redistributing routes, both SW2 and SW3 should know that, but if SW1<>SW2 link is up, it should chose that as the best path, but if that link is down, SW2 should still know of the redistributed routes via SW3 and use that as the best (and now only) path.

Do you have a copy of Packet Tracer?  If not, suggest you obtain one, as you could lab up your topology.

[Joseph W. Doherty]

If you do have a copy of Packet Tracer, open the attachment and you'll see the behavior I'm trying to describe (I believe the topology corresponds to your OP).