linking up/down state of serial0 to control Fastethernet0

[easternhemlock]

I have 4 Cisco 1721 each with a T1 wic installed; they are connected as redundant links that are connected at one end by a simple unmanaged switch. The other end is connected to a pair of Schneider Electric TF Switch which has allows redundant coupling of several network segments. And if I pull the primary patch cable it switch over just fine.
My problem is that if I pull/lose the T1 line the switch does not know that the T1 is down, and of course keep on sending data down a black hole. Is there a way to down the FastEthernet0 interface in the router when a T1 link/CD is lost??

 

[pmesjar]

Please explain yourself, why would you want to do that?

Peter Mesjar
CCNP, A+ certified
pmesjar@centrum.sk

"The only true wisdom is in knowing you know nothing.

 

[easternhemlock]

I need to down the Fastethernet0 interface so the the main switchs know that the primary T1 is down and to switch over to the backup T1. We don't use the T's as one big pipe as the data rate is not nearly close to any real load, but as 100% backup for both the T1's and the routers. I admit that this is not a normal set up as we are connecting PLC's with this system.

 

[pmesjar]

I guess I can't quite well imagine your setup. Could you please draw a logical diagram?

However if you are looking for a command built in an IOS, I am afraid but I don't have any info on a command, that would do what you need.

Peter Mesjar
CCNP, A+ certified
pmesjar@centrum.sk

"The only true wisdom is in knowing you know nothing.