RIP – Quick notes
RIP is a distance-vector Interior Gateway Protocol. It calculates the shortest path by evaluating the distance to reach the prefix (vector). The distance used by RIP is the hop count.
Routing updates are sent at a regular basis, which is 30 seconds by default.
There are two versions of the RIP protocol, where version 2 is the enhanced version. Version 2 enhancements includes multicast routing updates (224.0.0.9), variable length subnet masks support and message authentication.
In Junos by default all prefixes received from other RIP neighbors are automatically accepted but nothing is advertised. To advertise a route to another RIP neighbor you need to apply routing policy.
How to check the routes received from a neighboring router:
root@R1> show route advertising-protocol rip 172.16.0.2You need to specify the IP address of the neighbor sending the routes to local router. You should know the neighbor IP address as it is not seen from the neighbor table. You can find it using traceoptions or monitor traffic interface.
The command above is very useful and provides information on what is advertised by the local router to the RIP neighbors. As stated, you need routing policy to export routes from the routing table to RIP neighbors. The above command is not available for link state routing protocols like OSPF and IS-IS, because they do not advertise routes directly from the routing table. LSAs are originated from the link state database and stored there for processing.
How to check the routes advertised to a neighboring router:
root@R1> show route receiving-protocol rip 172.16.0.1Because RIP does not maintain a neighbor state and uses multicasts to reach other neighbors, you should specify the IP address of the local RIP router when using the show route advertising‐protocol rip.
The receive‐protocol option provides information on what is received by the local router from the specified neighbor. The output contains all routes before import routing policy is applied.
RIPng exchanges routing information used to compute routes and is intended for IP version 6 (IPv6)-based networks.
RIPng is a UDP-based protocol and uses UDP port 521.