RIP Limits

[vinuv]

HI,

Why RIP IS LIMITED TO only 15 hops , why not 32 or 63 hops.

[ruwhite]

Because the hop count field is limited to a number between 0 and 15.

Russ.W

[thisisshanky]

Distance vector protocols such as RIP have a lot of limitations, especially routing loops. You might be aware that RIP uses counting to infinity theory. If the system had several hundred networks, and a routing loop was formed, which involves the whole of the network, it would take more time to resolve, as well as more bandwidth would be consumed (considering updates being sent each time a change in metric is detected).

So there was a need to define "infinity" and once the hop count reached a value of 16, the route was considered as unreachable, thus removing the loop.

So the designers of RIP would have thought that this protocol is not scalable, and suggested an optimum value of 15, and not 32. If you compare a RIP design with 32 hops, it would take more time to converge, than a network with 15 hops.

I dont have an answer, for why it was not chosen as 16 instead of 15.

Hope that helps!

[milan.kulik]

I remember that it was possible to configure "network diameter" in RIP configuration on Wellfleet routers. But it was over 10 years ago.

But it was a dangerous feature - when you changed the value from default 15 to 32 in your network and connected a new router with the default value it could lead to unpredictable network behaviour and routing loops.

I agree with the others that the reason of the 15 hop limit is to provide a reasonable convergence speed.

Regards,

Milan