What is BGP?

distance-vector routing protocol

BGP (Border Gateway Protocol) is a protocol for exchanging routing information between gateway hosts (each with its own router) in a network of autonomous systems. BGP is often the protocol used between gateway hosts on the Internet.

Hosts using BGP communicate using the Transmission Control Protocol (TCP) and send updated router table information only when one host has detected a change.

BGP does not broadcast its entire routing table.

 

http://en.wikipedia.org/wiki/Bgp
enterprisenetworkingplanet.com/netsp/article.php/3615896/Networking-101-Understanding-BGP-Routing.htm
bgpexpert.com/what.php