HSRP IP for BGP peer

[jopetik09]

Hi All,

We have MPLS connected to 10.40.1.1 router, this IP have BGP peer with AT&T router.
Internet (DMVPN) connected to 10.40.1.3 rotuer.

Because of some other requirements we need to swap the LAN interface IP's of the both routers
As the DMVPN router IP as 10.40.1.1 and MPLS router IP 10.40.1.3

The problem is if I change the MPLS router IP 10.40.1.1 which is currently have BGP peering with AT&T then the MPLS connection will go down becuase of the BGP peering not up with AT&T untill AT&T change the new BGP peer IP at their end which will take so much of time (long process).

What I am thinking is, configure HSRP between MPLS & DMVPN router as 10.40.1.1 VIP.

Can someone tell me what will be pros & cons with the above?

Jopeti.

[milan.kulik]

Hi,

IMHO, it's not going to work.

a) AT&T would try to establish BGP peering to the virtual IP address then.

But your router would  have to use the virtual IP address as BGP update source.

AFAIK, it's impossible to configure on Cisco routers.

b) In a case the DMVPN router would become HSRP Active, it would have to peer with AT&T - but it has no peering configured probably?

BR,

Milan

[Latchum Naidu · Accepted solution]

Hi Jopeti,

First of all, I'm pretty sure that it is not even possible to establish a BGP session with a virtual IP address from HSRP. In order to establish the TCP session you would need to specify the virtual address as the update source. As far as I know you can only specify an interface which would use the assigned address for the TCP session.

And one morething that BGP works with TCP connections where HSRP works with UDP.

I think the EBGP is the best to test with the virtual IP. So, we no need the multi-homing. May try it out later.

Please rate the helpful posts.
Regards,
Naidu.