BGP Peering with HSRP Address

[jfraasch]

So this is one I can't figure out. Probably simple, yet complicated. I have two 3825 routers running HSRP and IBGP. One 3825 connects to Cogent, the other to Sprint both take full routes.

I am an ISP and have customers that will want to peer BGP directly with me. I want to give them the redundancy that I have built into my network with the HSRP...however, I understand that the customer routers CANNOT peer with my HSRP virtual address so that leaves me with...I dont know what!

So what do other people do in this situation? Have the customer peer with only one of the 3825's and hope that isnt the one that fails?

Please let me know your thoughts. This is a brand new installation and I can build it any way I want.

[pedroquiroga]

Hi, we have two customer access router (CAR), when we want to give redundancy to one customer which is speaking BGP with us, we usually bring up 2 bgp sessions with the customer, each of one with a CAR and we use local preference and metric to control which connection to use. With this configuration if one CAR goes down, the custormer traffic takes the other one.

I think you can peer with HSRP address too. But if one 3825 goes down, the traffic for the customer will be stop until the new bgp session goes up.

[jfraasch]

Thank you so much for the response. I thought it would be pretty easy to do. I don't get quite the failover with BGP that I would with HSRP but peering with both routers seems logical.

I had previously opened a case with Cisco and they told me that using the HSRP address would not work. I am not sure about putting the same IP Loopback address on two routers. I would think that too many things could go wrong with that.

Thanks again for the help. Keep the replies coming if there are any more ideas out there. I am a week away from implementing this network.

[Georg Pauwen]

Hello,

I have tried to lab this, and the only way I got it to work was to create a loopback interface with the same IP address on both HSRP routers, and then have the customer peer with that loopback IP address. Just make sure that the loopback IP on your two ISP routers does not become the router-id.

On the customer router, you then need two static routes to the loopback address configured on your routers, with different administrative distances.

I guess Pedro has a point, HSRP might not be the best way to configure redundancy in your situation (as an ISP), and local preference or weight are probably better suited...

Regards,

GP