Adding T1 to take over for Frame Relay?

[thomuff]

We are adding a T1 circuit to run from Location A to Location B Currently Location A and B has a two Frame connections. Look Below:

Currently

Router A1 -------768FR---------- RouterB1 ip ospf cost 1000 HSRP priority 120

Router A2 -------512FR---------- RouterB2 ip ospf cost 2000 HSRP priority 110

Future

Router A3 -------T1------------- RouterB3

cost 500 NO HSRP

I want to confirm that traffic will go through the T1 instead of the FR because it has lower cost. We do not want to affect HSRP. Long story.

Thanks

tom

[Richard Burts]

Tom

Without knowing what the real requirements are it is difficult for us to give you good advice. And your comment about long story sounds like there are requirements not yet described.

The simple solution would be to bring up the T1, configure it as an OSPF interface, configure an OSPF cost less than 1000, do not change routers 1 or 2 and do not change HSRP. The result will be that the routing decision favors sending traffic over the T1. If PCs are still configured with their default gateway as the HSRP address, then they will forward traffic to their gateway, which will recognize that it is not the best path to the remote and will forward traffic to router 3 to forward over the T1. The return traffic will come over the T1 to router 3 which will forward it directly to the PC.

An alternative would be to add router 3 to the HSRP group and give it a priority higher than router 1. This way the routing decision and the HSRP operation will agree. But I do not know how that would fit with your long story.

HTH

Rick

[thomuff]

Router A1 -------768FR---------- RouterB1 ip ospf cost 1000 HSRP priority 120

Router A2 -------512FR---------- RouterB2 ip ospf cost 2000 HSRP priority 110

Future

Router A3 -------T1------------- RouterB3

cost 500 NO HSRP

Update, We have a 4507 switch at each site. We are going to move the default gateway at Location A by moving configuring HSRP and setting the priority. At Location B, we are going to move the default gateway from the F0/0 interface on RouterB1 and assign to the VLAN interface on B4507. Moving forward, the Frame circuits will strictly be used for backup circuits to connect to Location B to Location A(Main site) OSPF routing will be configured on both 4507s.