[c-nsp] Static routes in routing table

[Chen, Qinxue]

We have two static routes to the same destination through two different next-hops. One static route has less prefered admin distance. We want a graceful failover happening when the primary static route fails. Now the question is how soon can Cisco routers take out the failed static route. If the next hop is on a direct-connected network (not necessaryly a point-to-point link,) that will depend on how soon the ARP table cleared on the Cisco router. There are two cases:

1) If cisco router -> next-hop is a point-to-point link, will the Cisco router flash the ARP entry for the next-hop right after the next-hop is down?
2) If the next-hop is connected to a cisco switch but on a direct-connected network as the Cisco router, will the Cisco router has to wait for the ARP timeout for the next hop to take out the failed static route? Or any other way to make it instantly.

Thanks

-Qinxue

-----Original Message-----
From: Rodney Dunn [mailto:rodunn at cisco.com]
Sent: Thursday, October 06, 2005 12:21 PM
To: Chen, Qinxue
Cc: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] Static routes in routing table


On Thu, Oct 06, 2005 at 12:12:21PM -0700, Chen, Qinxue wrote:
> I get a quick question:
> 
> If next-hop for a static route is unreachable, will Cisco routers put in the routing table? (What about Junipers?) Thanks
>

For Cisco.

Not unless the next hop recurses through a route that is up.

That's assuming you don't point at the interface and next hop or
you are not doing some form of object tracking.