The Exterior Gateway Protocol
) 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
). EGP is a simple reachability protocol, and, unlike modern distance-vector and path-vector protocols, it is limited to tree-like topologies.
During the early days of the Internet, an exterior gateway protocol, EGP version 3, was used to interconnect autonomous systems. EGP3 should not be confused with EGPs in general. Currently, Border Gateway Protocol (BGP) is the accepted standard for Internet routing and has essentially replaced the more limited EGP3.