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

Harold Ritter hritter at cisco.com
Sun Oct 16 10:20:25 EDT 2011


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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