Operation Manual – Routing ProtocolH3C S7500 Series Ethernet Switches Chapter 3 RIP Configuration3-1Chapter 3 RIP ConfigurationWhen configuring RIP, go to these sections for information you are interested in:z RIP Overviewz RIP Configuration Task Listz Displaying and Maintaining RIP Configurationz RIP Configuration Examplez Troubleshooting RIP Configuration3.1 RIP OverviewRouting Information Protocol (RIP) is a simple Interior Gateway Protocol (IGP), mainlyused in small-sized networks.3.1.1 RIP Working MechanismI. Basic concept of RIPRIP is a distance-vector (D-V) algorithm-based protocol. It exchanges routinginformation via UDP packets.RIP uses hop count (also called routing cost) to measure the distance to a destinationaddress. In RIP, the hop count from a router to its directly connected network is 0, andthat to a network which can be reached through another router is 1, and so on. To limitconvergence time, RIP prescribes that the cost is an integer ranging from 0 and 15. Acost value of 16 (or bigger) is considered infinite, which means the destinationnetwork or host is unreachable.To improve performance and avoid routing loop, RIP supports split horizon. Besides,RIP can import routes from other routing protocols.II. RIP routing tableEach router running RIP manages a routing table, which contains routing entries to allthe reachable destinations. Each routing entry contains:z Destination address: IP address of a host or network.z Next hop address: IP address of an interface on the adjacent router that IPpackets should pass through to reach the destination.z Interface: Interface on this router, through which IP packets should be forwardedto reach the destination.z Cost: Cost from the local router to the destination.z Routing time: Time elapsed since the routing entry was last updated. The time isreset to 0 whenever the routing entry is updated.
