Second BGP Process on a Router

[R0n1n]

We currently have one BGP process running on our router connecting to our Service Provider. Is it possible to create a subinterface, assign it to a VRF and then create a second BGP process within the VRF?

We are in the middle of separating some sites from our network that have MPLS connections to a new business. In the meantime, we'd have one MPLS connection to our MPLS network and a subinterface, VRF, and BGP connection to the same provider in a separate VRF in the MPLS network.

Hopefully what I am asking makes sense. Thanks in advance.

[Giuseppe Larosa]

Hello @R0n1n ,

a router belongs to a single BGP AS in Cisco implementation.

However, the command neighbor x.x.x.x local-as YYY was introduced in IOS and it is supported on IOS XE and IOS XR,

The command has several options and it was introduced for migration or for cases like your scenario

in your case the command has to be given within the VRF AF context on the PE node.

Hope to help

Giuseppe

[R0n1n]

Hi Giuseppe.

My apologies for the delayed response. But thank you.

So the second BGP AS can only be configured on the PE side of the link? Ideally, we'd do it on both the CE and PE routers to start the divestiture. And when it's complete, remove the first BGP process on both.

[Cristian Matei]

Hi,

    Not that this feature is not really like running a new BGP process, there are some restrictions happening, and the area meant for loop-free migration purposes. Read it to understand the end functionality: https://www.ciscopress.com/articles/article.asp?p=2756480&seqNum=16

    Configuration wise, you do it under BGP process, in the VRF:

router bgp 500

   address-family ipv4 unicast vrf TEST

     neighbor 1.1.1.1 remote-as 100

     neighbor 1.1.1.1 local-as 300 (no-prepend replace-as dual-as)

Regards,

Cristian Matei.