High Quality Content by WIKIPEDIA articles! The Exterior Gateway Protocol (EGP) is a now obsolete routing protocol for the Internet originally specified in 1982 by Eric C. Rosen of Bolt, Beranek and Newman, and David L. Mills. It was first described in RFC 827 and formally specified in RFC 904 (1984). Not to be confused with EGPs in general (of which EGP and Border Gateway Protocol (BGP) are examples), EGP is a simple reachability protocol, and, unlike modern distance-vector and path-vector protocols, it is limited to tree-like topologies.