Friday, January 23, 2009

Reliable static routing

Static routing is just that static. If an interface goes down the route remains in the table and potentially black holes traffic.

Reliable static routing gets around this problem by only installing a static route based on the the state of a tracked object. By using this feature static routes in effect become dynamic!

R1 --------------- R3

On R1 I reate an sla monitor to track the reachability of the loopback on R3

ip sla monitor 1
type echo protocol ipIcmpEcho
timeout 900
frequency 1
ip sla monitor schedule 1 life forever start-time now

I then create a tacking object

track 1 rtr 1

Router_1#s track
Track 1
Response Time Reporter 1 state
State is Up
5 changes, last change 00:00:02
Latest operation return code: OK
Latest RTT (millisecs) 1
Tracked by:

I then create a reliable static route based on the status of the tracked object 1

ip route 55 track 1

The route only remains in the routing table as long as the loopback on R3 remains reachable.


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