Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Two MPLS service prividers with OSPF issue

I have customer with multiple sites connected via MPLS WAN.

The same sites were linked with ( same bandwidth) the second MPLS service provider for link redundancy and load sharing.

Customer is running ospf.

Sooner when we connect a SINGLE location to the second service privider the routes originally learned from the first service privider were also updated as if they come from the second service provider. Obviusly this is wrong.

For example if I consider the route ( which is another branch connected ONLY to the service provider)

Before connecting to second service provider it looks like this;

O E2 [110/1] via, 05:00:08, Serial0

After connecting with the second service provider it becomes;

O E2 [110/1] via, 00:00:00, Serial1

Why does the branch router installs this route errornously and how do we isolate the problem ?


Re: Two MPLS service prividers with OSPF issue

Are you running two OSPF processes on your branch router i.e are you running OSPF as the PE-CE protocol for both providers ? If so, are they configured to use the default administrative distance ?


New Member

Re: Two MPLS service prividers with OSPF issue

Branch router serial 0 is connectted to SP#1.

serial 1 is connected to SP#2. One ospf process running in the branch router.

Yes , the PE-CE protocol is ospf for both SP's here.

SP says that they are running BGP inside their network and they are redistributing the ospf to BGP and vice-versa.

Re: Two MPLS service prividers with OSPF issue

Can you please post a "show ip ospf database external" with both LSA5 announcing the network in question?

With OSPF usually the truth is within the database.


New Member

Re: Two MPLS service prividers with OSPF issue

OK we can post the output but we have to wait for after-hours till the link becomes less critical.

( sooner the routing table populated with wrong paths, the branch cannot communicate since the actual traffic cannot go though Serial 1 connection for the simple reason that none of the other branches were connected via SP#1 at the moment.).