Chapter 10. RIP

Introduction

The Routing Information Protocol ( RIP) is an interior gateway protocol (IGP) that was developed as part of the ARPANET project and was included in the Unix BSD operating system in the early 1980s. RIP was widely deployed in the 1980s and became the industry standard for interior routing. It was standardized by the IETF in 1988, in RFC 1058. This version is referred to as RIP Version 1. RIP Version 2, defined in RFC 2453, added support for Classless Interdomain Routing ( CIDR) and authentication. RIP Version 2 MD5 authentication is defined in RFC 2082. RFCs 2080 and 2081 define RIPng, which is designed for IPv6 networks. JUNOS software supports RIP Versions 1 and 2, and RIPng.

RIP is a relatively simple protocol. It uses a distance-vector algorithm (also called the Bellman-Ford algorithm) to determine the best route to a destination. The distance is measured in hops, which is the number of routers that a packet must pass through to reach the destination. The best route is the one with the shortest number of hops. In the routing table, the router maintains two basic pieces of information for RIP routes: the IP address of the destination network or host and the hop count (metric) to that destination.

Every 30 seconds, devices on a RIP network broadcast RIP route information, which describes their view of the network topology and generates a lot of traffic on the network. RIP uses two techniques to reduce the amount of traffic:

Split horizon

A device ...

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