I'm in the process of setting up BGP between 2 ISPs at 2 data centers. From ISP A to data center A, I have 4 T1 lines configured with "ip load-sharing per-packet", from ISP B to data center B I have 1 T1, and I have a /24 assigned to me from ISP B to advertise. Between the 2 data centers I have a point to point T1 line going. My question is: Is it possible to use IP addresses from private class C to assigned to the interfaces that carry the point to point connection between the 2 date centers, then create loopback interfaces on the routers, assign these interfaces with ip addresses from the IP block that I'm advertising, then use "update-source loopback 0" to send routing updates between the two routers at the 2 data center (iBGP). Is it possible also to use an ip address from this IP block to assign to the ethernet interface that's facing with my internal firewall while this ip block is being advertised?
Since I have 4 T1 lines coming from ISP A, they asked to have a loopback interface set up which will be used to connect to their loopback interface on their router, is it still neccessary to set up "ebgp multihop".
We're mostly setting this up as failover, with as-prepending applied on the route out from IPS B, so that data center A will be the primary data center (traffic to this /24 IP space will go to data center A) until it goes offline, then data center B will take over all traffic to this /24.