RIP classful routing protocol

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Apr 26th, 2007
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Hi ........

i want to know what we means about classful routing protocol

i have completed my virtual lab with different subnets length and worked....

so .... how we say classful routing

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Richard Burts Thu, 04/26/2007 - 10:23
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The classful routing protocols make certain assumptions about networks and have certain behaviors. These include:

- the classful routing protocols support FLSM (Fixed Length Subnet Masking) and do not support VLSM (Variable Length Subnet Masking).

- they believe that any network can be subnetted but within a given network all subnets will be the same size. This results in a behavior that an interface will advertise subnets of its network that have the same subnet mask as the interface but will not advertise subnets of that network with a different subnet mask. it also leads to the behavior that the routing update does not contain subnet mask information.

- they believe that networks are contiguous and that you should be able to get from one subnet of the network to any other subnet of that network without going outside the network. This leads to the behavior that they always automatically summarize at network boundaries.



mohammedmahmoud Thu, 04/26/2007 - 16:23
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Hi Ibrahim,

Beside the nice explaination that Rick has provided, please check this document, its a nice one explaining how Classful routing protocols (RIP / IGRP) sends and receives updates:

Behavior of RIP and IGRP When Sending and Receiving Updates


Mohammed Mahmoud.


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