Lets just say I have three routers in full mesh. R1 has an uplink to an ISP publishing 220.127.116.11/24. Behind each router takes care of a subnet of the public block for web servers connected through a switch in three different locations like so:
18.104.22.168/26 - R1 (host gateway is 22.214.171.124)
126.96.36.199/26 - R2 (host gateway is 188.8.131.52)
184.108.40.206/26 - R3 (host gateway is 220.127.116.11)
I need to use BGP to advertise internally where each subnet is at, but from what I understand, its best practice in bgp to assign the IP address for each router to a loopback. This is not going to work because the IP address for each router needs to be on the interface facing the switches for each location.
So my question is:
Do I use private /31 networks between each router so they can talk iBGP or do I have to further subnet my public range to join them all together?
Alternatively, rather than using up 2 public IP addresses for each sub-network, would it be better to use 18.104.22.168/26 and put them all on the same subnet to talk (.1,.2 and .3) leaving room for .4+ for when I add new sites?
Cheers for reading my Q :)