BGP — Border Gateway Protocol

What is the Border Gateway Protocol (BGP)?

The Border Gateway Protocol is the routing protocol for the Internet. The BGP protocol specifies a TCP-based communications method for establishing routed peerings between Autonomous System (AS) border routers (ASBRs), that facilitate the exchange of information about routable IP prefixes. BGP peerings exist between all active Internet Autonomous Systems.

BGP is a path vector protocol, and BGP-enabled ASBRs send path vector messages to each other with lists of Internet-routable IP prefixes along with a Autonomous System (AS) path—the list of ASNs that must be traversed to reach that prefix.

BGP currently manages nearly 800K Internet-routable prefixes across the Internet.