RIP

What is RIP

RIP is an distance vector routing protocol and is using hop count as its routing metric - the less hops to the destination, the better.

To prevent routing loop, RIP implements split-horizion, which prevent routing information being sent out the same interface as it was received.
Combining split-horizon with poison reverse resulting a metric of 16, where a metric of 15 is the max amount of hops before a router consider a route as unreachable, therefore it tells the neighbors that a route is inaccesible rather than not saying anything.

RIPv1, among other limitiations, is limited to classfull routing and are therefore obsolete. Use RIPv2 instead, at least.

RIPv2	RIPng (Next Gen)	Facts
Classless routing	Same as RIPv2	Type	Distance Vector
Triggered updates	IPv6	Algorithm	Bellman-Ford
Global configuration	Interface configuration	Standard	Non proprietary
		Protocol	UDP
		Group	IGP

Configuration

RIPv2

Router rip
Version 2
No auto-summary
Network <Network adress>
Passive-interface [<Interface> | Default]

RIPng

ipv6 unicast-routing
Router rip <Name>
exit
int <interface>
ipv6 rip <Name> enable