Routing Information Protocol and comparing the three different versions

Routing Information Protocol and comparing the three different versions

In this article I will try to cover the three different versions of RIP which have been developed and evolved over years since 1988 and compare them briefly for quick reference.

Different vendors have implemented there flavor of RIP and this article is entirely focused on Cisco devices. As we all know every vendor implements it differently; but most of the core features remain identical.


The Routing Information Protocol commonly known as (RIP) has three version RIP v1, RIP v2 & RIPng.


Some of the common features among all three versions are mentioned below:

Common Features between RIP v1, RIP v2 & RIPng
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1. It is a Distance-Vector routing protocol.
2. The algorithm used is Bellman-Ford also known as distance-vector algorithm.
3. It is an “Interior gateway protocol" [ IGP ]
4. Uses hop count as the routing metric, limited to networks whose longest path involves 15 hops. The hop limit severely limits the size of network it can be used in.
5. Easy to implement.
6. RIP router transmits (advertises) full updates every 30 seconds by default.
7. Split horizon, Route poisoning and Holddown.

Default RIP Timers:
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Update timer = 30 seconds
Invalid timer = 180 seconds ( six updates periods 30 * 6 = 180 )
Hold down timer = 180 seconds
Flush timer = 240 seconds ( 60 seconds longer than the invalid timer )


RIP version 1 (v1)
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1. Is a classfull routing protocol. It was designed for class-based IP internetworks where the network ID can be determined from the values of the first 3 bits of the IP address in the RIP route.

2. Uses broadcast User Datagram Protocol (UDP) data packets to exchange routing information. UDP port 520 has been reserved for RIP.

3. Subnet mask is not included with the routes.

4. Does not support discontiguos (disjointed) network.

5. No support for authentication for RIP route updates.

6. Administrative Distance (AD) = 120

7. Does not support Variable Length Subnet Mask (VLSM).

8. No support for Classless Inter Domain routing (CIDR).

9. No Support for route summarization.

10. No support for Unicast Updates.

11. Does not support "route tags" tagging of routes to identify specific routes i.e. external redistributed routes.

12. Support for equal cost load-balancing.


RIP version 2 (v2)
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1. Is classless routing protocol.

2. Multicasted RIP Announcements, supports sending RIP announcements to the IP multicast address of 224.0.0.9. Broadcasting of RIP v2 announcements is also supported.

3. Subnet mask is included with the routing updates.

4. Subnets of a network ID do not have to be contiguous, they can be disjointed subnets.

5. Supports Authentication for RIP route updates i.e. clear text & MD5.

6. Administrative Distance (AD) = 120

7. Does support Variable Length Subnet Mask (VLSM).

8. Support for Classless Inter Domain routing (CIDR).

9. Support for route summarization.

10. Support for Unicast Updates.

11. Supports "route tags" tagging of routes to identify specific routes i.e. external redistributed routes.

12. Support for equal cost load-balancing.

RIP Next Generation (RIPng)
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1. Support for IPV6 was introduced.

2. It has no authentication facility as it was in RIP v2. It was designed behind the idea that it would rely on IPSEC within IPV6 stack itself.

Drawbacks / Limitations:
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1. Uses fixed "metrics" to compare alternative routes. It does not consider key features of a link i.e. ( Bandwidth / Delay / Reliability / Load )

2. Can be used ideally ONLY on small networks.

3. Limited to 15 hops than the network is considered as unreachable.