OSPF Default Route

[EMES]

We recently had a network event where a card in our core switch would not lock OSPF neighbors. I ended up rebooting this card and was able to restore services. However, I am confused why the network didn't alter the default route in the rest of our routers to redirect traffic. I have attached a simple diagram, red routers are ospf and green routers include BGP. My problem was the link between the green routers and when I tried to get traffic in a peer on the north side(north is up, right?!?) destined for a customer attached via BGP on the south peer, it goes from green to the red just north of it, once it got there, it didn't have a route in it's table for that southern peer, it only has the default route.

So...should it recalculate the default route or should I see a route in the routing table on that first hop away from the green so it doesn't use the default route. The default route is viable so I'm not sure that truly needs recalculated. I do have the following commands on the south BGP router:

enable ospf export e-bgp ExportToBGP
enable ospf export i-bgp ExportToBGP

that policy just states that all networks are accepted:
permit;
cost 2;
cost-type ase-type-1;

[Stephane_Grosj1]

Hi,

sorry I didn't come back to you before, the RIB was not very helping without knowing the BGP loopback addresses and the presence of the loopback in the IGP: what was my hint as your problem.

Looks like you have found it, good. I understand this was the reason, is it correct?

Regards,

[EMES]

I Believe this to be resolved. The two BGP Routers did not have a protected path for talking when the link was down.

This article, has a different point overall, outlines what I saw.

https://mpreath.wordpress.com/2014/10/04/how-mpls-reduces-routes-bgp-free-core/

[EMES]

Let me know where I can offer more detail.

Thank you to both of you!

[Stephane_Grosj1]

Hi, sorry, forgot to answer. A full RIB with BGP routers is usually a bad idea  I'm just interested in the prefixes causing pb and the default, with the info of the next-hop as well for each prefix. I don't need the real IPs, as long as you keep it consistent. So, if you can extract that info, stating clearly what router has what, just post it here.