MP-BGP and MPLS

[matthew8wilson]

Hello all,

I've been experimenting recently with MP-BGP and MPLS. I have no issues with how it works and how to implement and have a fully working lab however I am wondering whether there is a solution that exists in order to create a full mesh without on every PE router having to specify the IP address of every other PE router in the VPNv4 configuration. So the ideal scenario would be that i could add another site to my MPLS which will receive all routes from every other site without updating any configuration at any other site.

Thanks

[Emmanouil Patiniotakis]

The best solution for this is to use route reflectors. With this way its PE has only one neighborship to the RR and whenever you add another site you do not have to change anything on the existing ones.

[matthew8wilson]

I already have the P routers configured as reflectors, could you explain further?

The setup I have at the moment is as follows: CE1 -> PE1 -> P1 -> P2 -> PE2 -> CE2

[Nagendra Kumar Nainar · Accepted solution]

Hi Mathew,

You can choose P1 or P2 as RR and configure a single MP-BGP session from PE devices to RR. Any new PE that you want to include will need configuraion changes on RR and the new PE alone. You dont need to add configuration on other exisitng PEs.

You can also play around with bgp dynamic neighbor to further reduce the configuration. But I ahvent used it myself and not sure if VPNv4 is supported.

-Nagendra

[matthew8wilson]

Hi Nagendra,

I'm not sure what I am doing wrong then, I have all of the core routers configured as RR and each PE device is peered to a core but my PE's won't receive any routes from any other PE's unless I configure VPNv4 relationships between them. The VRF's are configured with the same import/export targets.

I'll upload some configuration when I'm at my computer, that may shed some light

[Emmanouil Patiniotakis]

You must configure VPNv4 relationships because this is the way to carry vrf-enabled routes. Otherwise it is not possible to carry routes coming form vrfs.

[matthew8wilson]

After some searching I came across the following topic:

https://supportforums.cisco.com/document/138646/configuration-exampleroute-reflectors-implemention-mpls-vpn

I've just tested this and it works brilliantly - your answer was correct but I now understand the PE VPNv4 configuration needs to point towards P routers running VPNv4 sessions with the others PEs and not between each and every PE.