Protocol gateway border or the BJP (BGP) is a routing protocol, from the type of External is the connection between autonomous systems it provides. There are protocols of this, for access to the global internet network is essential.

the main characteristics BJP can be to feature the amount of flexibility (Scalability), it is noted. This protocol in comparison with protocols such as OS, PHP, FTP, and AIG that to the number of routers in an AS or an Area restriction. due to the lack of need for direct connection of two routers in the network, this limit does not.

The BJP contains two types of internal or iBGP, and external, or eBGP. Type external IT between the two systems independent different runs and the type of interior it is also within an autonomous system. Usually, communication between routers in a state of iBGP full mesh is established. because the law prevent the creation of loops, a router does not allow routes received through an iBGP within its iBGP release.