MPLS MP-IBGP configuration

Unanswered Question
Apr 14th, 2009


I have configured following senario


PE1 -s1/0-

PE2 -s1/0-

I have configured the IBGP between PE1 and PE2 with physical interface IP address.

I can see the BGP session is UP between PE1 and PE2.

I have configured (activate) MP-IBGP between PE1 and PE2.

And i received the following message on the PE1 router.

%BGP-4-vpnv4NH_IF:next-hop may not be reachable from neighbour - not a loopback.

Can anyone please explain me what is this mean?

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Overall Rating: 5 (1 ratings)
Harold Ritter Tue, 04/14/2009 - 07:40


You should configure the VPNv4 session using the loopback interface address of the PEs rather than their physical interface IP address.

Using the physical interface IP address will most definitely cause issues.


ganpatspatil Wed, 04/15/2009 - 02:54

Thanks for the responce.

Can you please brief me in details what would be the issues ?

shivlu jain Wed, 04/15/2009 - 03:26

Explanation A VPNv4 route is being sent to the IBGP neighbor indicated in the messages. The next hop is one of the directly connected physical interfaces. It is possible that the label for the address of the next hop is being removed in the MPLS cloud one hop too soon. Because the provider (P) routers do not store VPN information, they do not know where to forward packets that carry the BGP label. If the address is not available at the correct hop, it could break connectivity between VPN sites.


shivlu jain


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