Appendix B. RIP (Routing Information Protocol)

This appendix covers the following topics:

• RIP Routing Table

• RIP Routing Convergence

• RIP Concerns

• RIP Routing Protocol Summary

RIP is a simple distance-vector routing protocol, and because RIP is an open standard, it is a safe presumption that any network routing device is capable of supporting RIP. RIP is an Interior Gateway Protocol (IGP) and is designed for use in small, simple networks. RIP was designed and engineered to support only Classful Routing and has no support for Classless Routing, such as CIDR (Classless Inter-Domain Routing).

NOTE

Interior Gateway Protocols (IGPs) are designed to convey routing updates within their own routing domain or autonomous system. Exterior Gateway Protocols (EGPs) are designed to convey routing updates between routing domains or autonomous systems.

RIP configured routers build a routing table, calculated from the information shared by the exchanging of routing information with each router's immediate neighbors. This routing table consists of one entry for each known (and reachable) destination. This entry is the lowest-cost path to that destination.

NOTE

The term cost when applied to routing tables and metrics is the total calculated value of that route. This cost is compared with the cost of other routes to determine the ideal path for traffic; the lower the cost value (closer to zero), the better the path.