This is part of the Cisco Notes series on Mike’s World News.
There are 2 versions of RIP that IPv4 networks can use as a Routing Protocol, namely RIP version 1 and RIP version 2.
Both RIP v1 and v2 are Distance Vector protocols. This means that the way they advertise routes is based on how far away in the routers are from each other. If, for example, to get from Router 1 to Router 4, there are are ways two get there, both RIP v1 and v2 will count how many routers are each way and go the way with the fewest routers. This is referred to as a Hop Count.
See image below:
In this example, Router 1 can communicate with Router 4 either by talking to the router directly (1 Hop), or by talking to Router 2. then 3, and then finally 4 (3 Hops). RIP v1 and RIP v2, regardless of the speeds of the connections will always go from Router 1 to Router 4.
Every 30-seconds, the full routing table is sent to all other routers. RIP v1 does this as a broadcast (255.255.255.255) and RIP v2 does this as a multicast to 224.0.0.9.
The Administrative Distance of RIP is 120.
RIP will load balance equal cost links. So, in the example above, traffic from Router 1 to Router 3 will be load balanced, with half going via Router 2 and half going via Router 4. By default, it will load balance up to 4 paths.
RIP uses Split Horizon, which prevents a Router update across the same interface that received it.
By default, RIP wil use Auto Summerization.
RIP v1 is a Classful Routing Protocol. It does not, therefore, support Variably Length Subnet Masks (VLSM) or CIDR.
RIP v2 does support both VLSM and CIDR.
1 Comment
In an effort to avoid unnecessary load on hosts that do not participate in routing, RIPv2 multicasts the entire routing table to all adjacent routers at the address 224.0.0.9 , as opposed to RIPv1 which uses broadcast. Unicast addressing is still allowed for special applications.