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

OSPF Route Summarization and BGP


I have the following scenario. We are running OSPF on our LAN Core's and have Radio links as our Primary path back to the HQ, and MPLS Links (diginet) as backups on all our sites. We then have a Regional Data Centre (called RDC) inside the MPLS that needs to talk to all of the LAN networks via the MPLS but preferred path would be via the BSS (Business Systems backbone HQ Offices ) and then over the Primary path aka Radio links to all the various Sites. All Sites default gateway would be the BSS Core via the Radio links and like I said if a site Radio fails, it needs to switch over to their Local MPLS Router.

I have configured a GNS LAB with all the various sites and configured OSPF on the Site Core's and BGP on the MPLS. Routing is working as it should, I.E OSPF is redistributed into the BSS MPLS Router and all the Sites have full access to the RDC and back via the Preferred path aka BSS Core.

Now, I have tested the failover by  shutting the Radio link interface of a Site, then failover happens via the MPLS Routers to the RDC and traffic from RDC back via the Site MPLS Router (not the BSS Core where the Radio links are) Un shut the interface and traffic switch over from MPLS to Radio Links as it should.

Problem: When I implement summarization on the LAN Core's in OSPF with command "area 1 range network range" all the other LAN Core's learns the new Summarized /19 or /21 of each site as they should . (making the routing tables on the LAN smaller, better) BUT, the RDC routes the Site traffic into the MPLS Cloud, and then route the Site traffic directly to the Site MPLS Routers, and not Via the Preferred BSS backbone Radio links path as previous.

Question: Why would BGP learn all the Site individual routes aka /19 or /21 but not take the summary route as desired ? (summarization will then happen on MPLS and LAN)

Am I missing something....

Hall of Fame Super Blue

OSPF Route Summarization and BGP

Just a few questions for clarification -

1) are you redistributing BGP back into OSPF ? I assume you are.

2) the radio link path, is that via the SSC-MPLS router ?

3) if it is you are showing EIGRP between the left hand side and the OPSF LAN so how are you doing route redistribution here ?

4) your explanation suggests you do the OSPF to BGP redistribution on the BSS MPLS router only. But i would have though all LAN site routers (BOS-MPLS, RHO-MPLS etc.) would need to advertise their networks (otherwise why have multiple MPLS links which would never be used)

5) i may be missing it but is OSPF all in one area ?

Apologies if i have misunderstood how it is working.

If i have perhaps you could clarify.


CreatePlease to create content