Border Gateway Protocol
A routing protocol often associated with the Internet. BGP can be used between gateway hosts on the Internet. BGP examines the routing
table, which contains a list of known routers, the addresses they can reach, and a cost metric associated with the path to each router so that
the best available route is chosen. BGP communicates between the routers using TCP.
Some literature classifies BGP as a distance-vector routing protocol, it can more accurately be described as a path-vector routing protocol, meaning that it can use as its metric the number of AS hops that must be transited to reach a
destination network, as opposed to a number of required router hops. BGPs path selection is not solely based on AS hops, however. BGP has a variety of other parameters that it can consider. Interestingly, none of those parameters
are based on link speed. Also, although BGP is incredibly scalable, it does not quickly converge in the event of a topological change.