Implementing a BGP Core
If building a BGP core is the right design choice, what is the next step? How would you go about implementing a BGP core? There are three fundamental issues that need to be addressed before discussing the BGP core design itself: Should each separate routing domain within the network connect via eBGP, or should the core run iBGP to connect these separate routing domains; how should routing in the core itself be handled; and what sorts of information should be exchanged between the core of the network and each of the separate routing domains?
eBGP Cores versus iBGP Cores
The first issue we need to address is whether each routing domain will be in a separate autonomous system or they should all be in the same autonomous system. ...