multi-hop BGP4

[tato386]

My company has a large T1 private line network which is using private IPs in the 10.X.X.X range. The company has an Internet connection at corporate and all Internet destined traffic from the remote sites is routed over the private network and out the connection at corporate. I am located at one of the remote sites and we would like to add our own Internet T1 for redundancy purposes. Our ISP is providing us with a full Class C public block that we would like to advertise via our ISP and also via the corporate ISP. Since the corporate ISPs router is not adjacent to ours I would like to use multi-hop BGP to talk to the corporate ISP and standard BGP setup for our ISP.

Is this possible? Will the fact the the corporate ISPs BGP router is not adjacent to ours and also several hops away via a private network prevent this from working?

Thanks,

Diego

[thisisshanky · Accepted solution]

Ebgp multihop works even if the neighbor is upto 255 hops away.

command used is , "neighbor ebgp-multihop

where X is the number of hops.

Make sure the neighbor ip address specified is reachable via your IGP.

[thisisshanky]

Since you might be using the same AS number on both the routers, you really wont be running EBGP between the routers. But instead, it will be IBGP (since AS numbers are same..). IBGP doesnt need any Multihop configurations. If the neighbors are not adjacent, only thing that needs to me made sure, is reachability via IGP.