Tshoot unequal cost OSPF routes

[thetonaka88]

How do I troubleshoot unequal cost routes in OSPF. The database doesn't show route cost, so unless I stop advertising the currently installed route I cannot find a way to learn the cost of the route that is not preferred/installed.

[thetonaka88]

Can anyone help me with this?

[grinch182]

Could you please discribe your situation more clear?

[thetonaka88]

Not sure how to be more clear....

I want to know the cost of (higher cost) routes that are obviously not installed into the routing table (due to being higher cost).

An example of this would be

[WAN Edge X] --- [Router A] - [ Core Router ] - [Router B] - [Router C] - [WAN Edge Y]

WAN Edge X and WAN Edge Y both get routes from our from our MPLS cloud, both are injecting them into OSPF. But (all links being equal speed, hence also equal cost) only X's routes get installed/ used by the Core Router. Without shutting down X, or manually calculating the cost, how can I tell the cost that the core see's for Y's routes? (Why do I want to? In this example, lets say I want to do equal cost multipath load balancing.... )

That's as simple as I can explain it.

[Jon Marshall]

I understand what you mean but to my knowledge there is no way to do this.

The problem is that OSPF does not exchange routes between routers, it exchanges LSAs which you can view in the OSPF database but these are not the actual routes you are looking at. So it's not like when you view the EIGRP topology table where you see all routes being exchanged.

Like i say, i could be wrong but i can't see how you could view this. You would simply need to know the costs along each path and work it out from there.

Jon

[thetonaka88]

I understand this, but the LSA's contain the topology information. The router has the cost, it uses it to run SPF. It just seems insane that there is no way to see this information... I thought maybe I had been missing something all of these years, some trick that all the other engineers knew except me!!

[Jon Marshall]

Well if there is a trick then i don't know it either