What is Cisco RIP Protocol?
The origin of the RIP was the Xerox GWINFO protocol.
A later release was known as directed in 1982, Berkeley Standard Distribution (BSD), distributed with Unix.
RIP has evolved as an Internet routing protocol and other proprietary protocols use modified versions of RIP.
For example, Apple Talk Routing Table Maintenance Protocol (RTMP) and Banyan VINES Routing Table Protocol (RTP) are based on a version of the RIP routing protocol.
The latest development in RIP is the RIPv2 feature, which allows more information to be included in RIP packets and provides a straightforward authentication mechanism.
This is what RIPv2 needs to learn for CCNA; it is still the version you can see on some computers.
What is Routing Information Protocol
RIP is a dynamic routing protocol of the vector distance type, i.e., the best route for a given destination for RIP is the one with the least number of hopes.
In Router and Routing – Dynamic Routing, you can understand the concept of distance vectors in detail.
One detail to keep in mind at all times is the skip limit.
This limit of 15 hopping for the two protocol versions did not develop in the new version.
If I must pass more than 15 routers to reach my destination, my package will be thrown on the road.
As you can imagine, this directly affects the scalability of the protocol.
Although, at that time, a protocol that meets the moment’s needs, RIP today is well below the challenges of modern data networks.
Now you can ask me why we saw it.
Many companies still use it for little information or a technical decision.
For example, we used RIP as a redundant network protocol in one of the networks I met because it contained a high AD (Management Distance).
For those wondering, the RIP has an AD value of 120.
Messages
RIP messages can be of two types:
- Request: sent by a recently started router, requesting information from neighboring routers.
- Reply: messages containing routing tables are updated. There are three types:
Average messages: Sent every 30 seconds. To indicate that the link and route are still active. The entire routing table is sent.
Messages sent in response to request messages.
Messages are sent when cost changes. All routing table is sent.
Working mode
When the RIP starts, it sends a message to each neighbor asking for a copy of the neighbor’s routing table.
This message is a request with “address family” in 0 and “metric” in 16.
Neighbor routers return a copy of the routing tables.
When the RIP is in active mode, it sends all or part of the routing table to its neighbors every 30 seconds.
The routing table is sent in response, even if the request is absent.
When a measurement changes, it is broadcast to other routers.
The message is confirmed when the RIP receives a response, and the local table is updated if necessary.
You learned one route from another; you must save it until you find a more cost-effective way.
This prevents routers from oscillating between two or more paths at equal cost.
The routes that the RIP learns from other routers end unless they are broadcast again in 180 seconds, i.e., 6 seconds and 30 seconds.
When a route expires, its metric is set to infinity, the invalidity of the course is distributed to the neighbors, and it is deleted from the table after 60 seconds.
The information is published in the first and second versions by multicast (224.0.0.9).
Advantages and disadvantages
RIP’s main advantage is its configuration’s simplicity, which makes it very easy to implement.
Contrary to its simplicity, there are disadvantages.
One of the most important of these is to be a distance-vector protocol that is very limited in modern networks.
Today we can imagine this because we show significant differences in connection speed.
Another disadvantage is the very long convergence time.
And let’s not forget the 15-jump limit.
Can you imagine a protocol that limits you to 15 steps in a globalized world?
Reference
