What you should know about BGP-4 Protocol
Border Gateway Protocol Version 4 (BGP-4), documented in RFC 1771, is the current exterior routing protocol used for the global Internet. BGP is essentially a distance-vector algorithm, but with several added twists. Other BGP-related documents are RFC 1772 (BGP Application), RFC 1773 (BGP Experience), RFC 1774 (BGP Protocol Analysis), and RFC 1657 (BGP MIB).