Two Routers One Routing Issue

mrashby · ‎10-21-2009

All,

I have two core routers, one has a T3 connected to it the other an OC3. The T3 connects to my core 2 switch and the OC3 connects to my core 1 switch. It is all EIGRP for the routing protocol. The T3 is strictly for backup I am not doing any load balancing. My issue is that some times the T3 router advertises routes that sometimes screw up a couple of my branch sites. By that I mean the branch site will not be able to get to a particular destination on the WAN. What usually fixes the problem is me clearing the routing table on the T3 router and then all is right with the world again. Obviously I don't want to have to keep doing this. What I want is for the T3 router to be in a total backup capacity. If the OC3 goes down the routing protocol recognizes there is another way out via the T3 and advertises that. I tried to play around with some of the metrics on the T3 router but that doesn't seem to help. Any thoughts?

andrew.prince · ‎10-21-2009

You may consider doing the following:-

1) Use interface delays

2) Use HSRP between the 2 routers, having core1 be the primary and track the interface connecting to the OC3.

3) Use IP SLA to monitor connectivity over the OC3 to the remote end, in the event of a mid-circuit break - core2 takes over.

HTH>

mrashby · ‎10-29-2009

Andrew,

The more I think about it I am liking the HSRP option. I have a question since I have never configured HSRP before. From what I currently understand there will be a virtual address involved. Will I have to have any static routes in my core switches to route traffic to the virtual HSRP adddress or will EIGRP take care of that?

Edison Ortiz · ‎10-29-2009

Static route pointing to the VIP. The VIP does not participate in the dynamic routing protocol, the physical interface IP does.

Regards

Edison