The Gateway-to-Gateway Protocol (GGP) is an obsolete
protocol defined for
routing
Routing is the process of selecting a path for traffic in a network or between or across multiple networks. Broadly, routing is performed in many types of networks, including circuit-switched networks, such as the public switched telephone netw ...
datagrams between
Internet gateways. It was first outlined in 1982.
The Gateway-to-Gateway Protocol was designed as an
Internet Protocol (IP) datagram service similar to the
Transmission Control Protocol (TCP) and the
User Datagram Protocol (UDP). However, it is classified as an
Internet Layer protocol.
[, ''Transport Protocols For Department of Defense Data Networks'', National Research Council, (February 1985), p.17]
GGP uses a ''minimum hop'' algorithm, in which it measures distance in router hops. A router is defined to be zero hops from directly connected networks, one hop from networks that are reachable through one other gateway. The protocol implements a distributed
shortest-path methodology, and therefore requires global convergence of the routing tables after any change of link connectivity in the network.
Each GGP message has a field header that identifies the message type and the format of the remaining fields. Because only core routers participated in GGP, and because core routers were controlled by a central authority, other routers could not interfere with the exchange.
See also
*
Distance-vector routing protocol
*
Link-state routing protocol
*
Router Information Protocol
References
{{compu-network-stub
Internet layer protocols