To prefer an OSPf route Over an IS-IS Route at IP Edge Router

Hi @sachandio!

How does a router decide which routes are optimal?

For routes learned from different protocols but with the same network prefix, please do the below.

Compare the external priorities of the protocols:

a) the smaller the external priority, the higher the priority;

b) if the external priorities are the same but learned from different protocols, compare the internal priorities. A smaller priority value indicates a higher priority;

c) if the external priorities are the same and the protocols are the same, compare the internal metrics of the protocols.

So you need to change the external preference of the routing protocol.

The default external priority of OSPF is 10 and that of IS-IS is 15. Therefore, the router preferentially selects OSPF routes.