How to detect ethernet path failure and clear dynamic routes on that path on cisco router
Posted on 2009-02-19
I have routers that are interconnected via two independent fast-ethernet paths for redundancy and load sharing (Per-Destination).
I have used the ip sla and track features in the IOS to auto-fail a default route based on reachability of the far end ethernet interface IP address and it works very well.
However, I have dynamic routes advertised on both ends that need to see each other. When one path goes down, the default route fails over within 3 to 5 seconds. But the dynamic routes ( using RIPv2) don't fail -over for the full 180 seconds time-out that is the RIP route time-out timer.
Is there a way to signal / remove RIP on the failed path interface so the dynamic routes get pushed over to the redundant path quickly? The RIB should have both routes and the fail-over should happen as quickly as it takes the RIB to update to the FIB.
I know if I could shutdown the interface on the failed path, this would force a routing update on the RIB and FIB. But then I could no longer monitor the path to see when it comes back up.
Use VLANs on the path maybe? One VLAN to carry traffic and another strictly for monitoring?
I could shutdown the traffic VLAN forcing the routing re-set while leaving the monitoring VLAN up to detect when the path comes back up
I have no idea on how to or if an interface can be shut down via a track object