Points to Remember

• RIP uses hop count as a metric to calculate the best routing path to a destination network.

• RIP uses the Bellman-Ford algorithm to compute the metric used for routing path decision.

• RIPv1 is a classful routing protocol, does not carry subnet information, and is incapable of supporting Variable Length Subnet Masking (VLSM).

• RIPv2 is a classless routing protocol and supports VLSM and authentication.

• The common problems encountered in RIP environments are misconfiguration, classful routing, classless routing, timers, looping, and version incompatibility issues.

• RIP is activated using the command router rip.

• The syntax for assigning the network is network network number.

• Routing convergence means ensuring that the routing information about the entire network is registered with all the participating routers.

• To verify the routing protocol configuration on a router, use the command show ip protocols.

• The command to view the routing table of a router is show ip route.

• The command to check router configuration with a passive interface is show running-config.

• To create equal cost path routes for a router, use the command maximum-path <path #>.

• The process of consolidating all subnet routes of a major network while crossing the boundaries of another major network is called autosummarization.

• To verify a RIPv2 protocol configuration for different routers, use the command show ip protocols.

• To debug a router RIP message, use the command debug ip rip.

• RIPv2 cannot reach discontiguous networks by default.

• Timers dictate and influence the RIP routing calculations and their operating behavior.

• Four types of timers associated with RIP are update, invalid, flush, and hold-down.

• Invalid timer is also referred to as an expiration timer.

• Flush timers maintain routing tables for unreachable routers for a certain period of time. They are also called garbage timers.

• Hold-down timer refers to the period for which the router waits to receive information about an invalid route, ignoring any updates about the route.

• To counter looping effects, RIP uses certain features, which include hop count, split horizon, route poisoning, triggered updates, and hold-down timers.