[c-nsp] Running OSPF on PE-to-CE

[Harold Ritter]

I did not mean to check at the RIB on the PE but rather at the BGP table.
You will see that the locally originated route (redistributed from ospf) is
preferred over the one received via VPNv4.

De :  ar <ar_djp at yahoo.com>
Répondre à :  ar <ar_djp at yahoo.com>
Date :  Mon, 17 Oct 2011 15:33:25 +0800 (SGT)
À :  Harold Ritter <hritter at cisco.com>, "cisco-nsp at puck.nether.net"
<cisco-nsp at puck.nether.net>
Objet :  Re: [c-nsp] Running OSPF on PE-to-CE

Hi. The PE actually prefer the one via OSPF learned from CE (Intra-area). It
has admin distance of 110 compred to 200 of MP-iBGP.



From: Harold Ritter <hritter at cisco.com>
To: ar <ar_djp at yahoo.com>; "cisco-nsp at puck.nether.net"
<cisco-nsp at puck.nether.net>
Sent: Sunday, October 16, 2011 6:20 AM
Subject: Re: [c-nsp] Running OSPF on PE-to-CE

This is normal behavior. If you look at the PE you will see that the
locally originated route (the one redistributed from OSPF) has a weight of
32768, which makes sure that this route always win over the one received
from the other PE via BGP VPNv4.

Regards



Le 11-10-16 04:02, « ar » <ar_djp at yahoo.com> a écrit :

>    
>
>Can somebody tell me why this route is being prefered?
>
>I have 2 customer edge router. one on each site. The are linked together
>running ospf for intra-area routes. Multihomed to the MPLS VPN service
>provider using OSPF also as PE-to-CE  routing protocol. Routes are
>redistributed so they are both E2 routes.
>
>Here's the outpu from one of my CE. I am trying to check show ip route
>the loopback address of CE2 from CE1.
>
>
>Here's the route of CE-2's loopback via the MPLS/VPN
>
>
>CE1#sho ip route 10.30.30.30
>Routing entry for 10.30.30.30/32
>  Known via "ospf 10", distance 110, metric 1
>  Tag Complete, Path Length == 1, AS 10, , type extern 2, forward metric 1
>  Last update from 172.16.2.1 on FastEthernet0/0, 00:01:47 ago
>  Routing Descriptor Blocks:
>  * 172.16.2.1, from 10.2.2.2, 00:01:47 ago, via FastEthernet0/0
>      Route metric is 1, traffic share count is 1
>      Route tag 3489660938
>
>
>Here's the CE-2's loopback via the Intra-area link. (elected as best path
>always)
>
>CE1#sho ip route 10.30.30.30
>Routing entry for 10.30.30.30/32
>  Known via "ospf 10", distance 110, metric 20, type extern 2, forward
>metric 1000
>  Last update from 172.16.3.1 on FastEthernet1/0, 00:00:08 ago
>  Routing Descriptor Blocks:
>  * 172.16.3.1, from 10.30.30.30, 00:00:08 ago, via FastEthernet1/0
>      Route metric is 20, traffic share count is 1
>
>
>Loopback IP is just redistributed to OSPF so it should be an E2 route.
>
>However based on the two routes above, the one via the intra-area link is
>always being prefered over the one via the MPLS network even if I adjust
>the redistribution metric. Both are E2 routes already. What's the
>difference between the two routes and why the other is being prefered
>always regardless of metric set?
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