Exterior Gateway Protocol

The term Exterior Gateway Protocol (often given as its acronym, EGP) has two meanings: first, the generic one, meaning a routing protocol used in the TCP/IP protocol suite for providing the information needed for doing path selection between a connected group of Autonomous Systems, and second, a specific protocol which was the first EGP.

The EGP protocol is now obsolete, and no longer in use. It was a Destination Vector protocol; the data it carried was routing table entries.

It did not have any mechanism for detecting and preventing routing loops; EGP was only intended for use in networs in which the graph of AS connectivity did not contain any cycles. The current EGP, BGP does not have this limitation.