Using “floating” static routes with IP SLA: in the following example, there are two routes (one to a specific ISP router, for instance), one with a default AD (1 for static) that is tracked by an IP SLA reachability operation, and also a second route with an AD of 254 that is not inserted into the routing table unless the IP SLA operation fails and the tracked route is thereby removed (thus inserting the AD 254 route for dynamic path control).
To use the IP SLA within a policy-based routing configuration (to allow for more granular classification of traffic and action thereof), observe the following example:
… in this example, the route-map is configured to match an ACL called PBR-ACL. The first set statement includes the command verify-availability which sets the condition to either use (operation: up) or bypass (operation: down) the set ip next-hop command on that line. Note both set statements are configured with an AD, and both are valid, but only the AD 1 route will be observed due to its superior AD unless the IP SLA operation fails fails.
Note that the use of the verify-availability command potentially allows an administrator a lot of flexibility in setting multiple next-hop options if multiple tracking statements are configured.
Stuck-in-Active: Journal of an IT-Network Administrator 