Question: what is the difference between internal and external bgp?
Answer: And BGP can run in two modes that each has a very different behavior when advertising routing information. EBGP: external BGP runs between routers in different ASs. IBGP: internal BGP runs between routers in the same AS. EBGP: routes received from an EBGP peer can be advertised to EBGP and IBGP peers.