Thanks. Yes. E3, THCC_1, THCC_2 are running EIGRP.

What about Test_1 & Test_2 ? are they too running EIGRP.

No they are not.

What is the output When you do a

show ip route

on the Test_1 when the Link between THCC_1 & Test_1 is down.

Is there any reason that Test_1 is not runnign EIGRP

IF you do not want to run EIGRP on Test_1, then you have to put 2 static default Routes on it with different metrics - one pointing to 10.90.153.101 & 10.90.153.2

Then the return packets will flow back to E3 & you will be able to ping to Test_1 from E1

The same will be the case for Test_2

With regard to your design.

what are you connecting on various switches ?

Thanks.

I've turned on EIGRP on both Test_1 and Test_2.

It re-routes fine when I disconnect either (THCC_1 to Test_1) link or (THCC_2 to Test_2) link.

But now the problem is when I disconnect the link between Test_1 and Test_2, I lose connection to Test_2 because E3 thinks the route to it is still via THCC_1 and Test_1.

Test_1 and Test_2 will have client computers

connected to them. If I have one DHCP scope

for the 10.90.153.0/24 network, what should the router be set to? Test_1 or Test_2?

What are the subnet masks for the various IPs

What are the functions of E1,THCC_1 & THCC_2 switches