To begin configuring a BGP network, you need to establish a connection between the current device and a counterpart, adjacent device known as a neighbor or peer. While this may seem like unneeded information at first, it is actually central to the way BGP works. Unlike OSPF, you now have to configure two devices, both the current router and its neighbor, for BGP to work. While this requires more work, it enables networking to occur on a larger scale as BGP eludes deploying the limited advertising techniques inherent to interior networking protocols.

There are two types of BGP neighbors: internal neighbors which are in the same autonomous system and external neighbors which are in different autonomous systems.