Problems with BGP and MPLS

Answered Question
Jul 11th, 2007

I have a provider edge router (PE) that is connected to a core router (core1) via eBGP. Core1 is connected to Core2 via IGP. A VRF was configured between PE and Core1 for a customer. We now have to extend that VRF to core2. When the configuration is put in, BGP works normally on the circuit, but the eBGP learned next-hop (PE) is shown as the next hope for routes on Core2, which cannot contact that router over the VRF.

Based on Cisco's configuration for eBGP and iBGP using next-hop-self, I tried to apply that via a neighbor statement within the vrf. Im now getting duplicate routes with change the vrf's route every minute or so. And Im not able to pass the traffic, which was the problem in the first place.

Attached are the configs for both the Core1 and Core2 routers, as well as the ip bgp vpnv4 vrf CustomerA statement from Core2 showing the weighted but duplicated routes.

Any help on a better way to do this would be appreciated.

Thanks

Greg

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Correct Answer by vassiliev about 9 years 4 months ago

I look your MPLS.txt, look the core1 config.

router bgp XXXXX

bgp log-neighbor-changes

neighbor 10.0.0.82 remote-as 65512

neighbor 10.0.0.82 update-source Multilink12 <<<<

and CORE 2 config:

!

router bgp XXXXX

bgp log-neighbor-changes

neighbor 10.0.1.1 remote-as XXXXX

neighbor 10.0.1.1 update-source Multilink1

!

why only one neighbor? where is the PE2 ?

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gregwoodson Wed, 07/11/2007 - 14:09

This whole problem might be simpler due to this. From Core2, I cannot ping 10.0.1.1 from within the VRF. If I could do that, I could apply the neighbor next-hop-self on the main address family and solve this issue.

Greg

Correct Answer
vassiliev Wed, 07/11/2007 - 21:33

I look your MPLS.txt, look the core1 config.

router bgp XXXXX

bgp log-neighbor-changes

neighbor 10.0.0.82 remote-as 65512

neighbor 10.0.0.82 update-source Multilink12 <<<<

and CORE 2 config:

!

router bgp XXXXX

bgp log-neighbor-changes

neighbor 10.0.1.1 remote-as XXXXX

neighbor 10.0.1.1 update-source Multilink1

!

why only one neighbor? where is the PE2 ?

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