Internet > How
the Internet works > Routing >
IGP Protocols >
Routing Information Protocol (RIP)
The Routing Information Protocol (RIP) provides the standard IGP protocol for local area networks, and provides great network stability, guaranteeing that if one network connection goes down the network can quickly adapt to send packets through another connection. The following subsections describe how RIP was invented, how RIP works, and other RIP resources.
How RIP was invented. The Routing Information Protocol (RIP) was written by C. Hedrick from Rutgers University in June 1988, and has since become the most common Internet routing protocol for routing within networks.
RIP is based on the computer program "routed", which was widely distributed with the Unix 4.3 Berkeley Software Distribution (BSD) operating system, and became the de-facto standard for routing in research labs supported by vendors of network gateways.
All RIP routing protocols are based on a distance vector algorithm called the Bellman-Ford algorithm, after Bellman's development of the equation used as the basis of dynamic programming, and Ford's early work in the area.
Software based on these algorithms was used as early as 1969 on the ARPANET, but the main protocol development was done by the Xerox network research and development division. The earliest RIP protocol was the PUP protocol, which used the Gateway Information Protocol to exchange routing information, and was invented by a team that included R. M. Metcalfe, who later developed the Ethernet physical layer network protocol. The PUP protocol was later upgraded to support the Xerox Network Systems (XNS) architecture, and named "Routing Information Protocol", usually just called RIP.
How RIP works. What makes RIP work is a routing database that stores information on the fastest route from computer to computer, an update process that enables each router to tell other routers which route is the fastest from its point of view, and an update algorithm that enables each router to update its database with the fastest route communicated from neighboring routers:
D. P. Bertsekas and R. G. Gallaher proved the RIP algorithm converged to the best estimates of distance to each destination address.
The RIP routing protocol uses UDP because it is particularly efficient, and there are no problems if a message gets, which is fine for router updates where another update will be coming along shortly anyway.