I'm attempting to wrap my head around a very critical piece of setting up BGP between 2 ISP's concerning how many Virtual Routers are required. I currently have 1 ISP (A) up and running on BGP just fine and my other ISP (B) will be converted to BGP on Monday. Both will be advertising my public IP space from ARIN. So my question is, do I put both ISP A's and ISP B's interfaces on the same VR or do they need to be on their own separate VR's? I'm receiving a few conflicted answers to this question, so I'm looking for real world experience. Currently I'm still a strong believer in that I need to just add my ISP B as its own Peer Group to my current primary Virtual Router, add ISP B's own subinterface to the Resdistribution Profile along with ISP A's subinterface, configure a new Import Rule for ISP B plus an Export Rule with a Prepend of 2 if I choose to, and finally check ECMP for "load balancing". All this sounded great until I was told the following from a Palo rep: " Two interfaces ( belonging to same VR ) cannot have IP addresses from the same subnet. x.x.x.x/24" That threw a wrench into my whole thought process because both ISP's are advertising my /24 from ARIN, but are physically connected with 2 different /30's to each ISP's switch.
... View more