Subject: dvmrp prunes

From: [email-masked]
Date: Tue, 25 Jul 2000 10:01:22 +0530

Hello Sir,
 I would like further clarification in the matter of source/mask in dvmrp prunes.

If it is argued that the source addres corresponds to 'source network' and the mask is used to 
associate with a route then it means that the prune applies to a route rather than a source. 
Hence even if a host address (not net address) is given in the prune it will prune the route to 
the source-network. Hence all traffic from the source-network will be pruned. But, if it is 
desired to prune traffic only from a particular source or set of sources in the network then this 
strategy will not work. If the forwarding cache maintains host-group(S,G) flow and prune 
applies to this then it will give the flexibility of  pruning a set of sources in the net. Will this 
method give better flexibility. Please clarify.

Regards,
Vijay

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From: Bill Fenner <[email-masked]>
Date: Tue, 25 Jul 2000 10:02:30 -0700

>If it is argued that the source addres corresponds to 'source network'
>and the mask is used to associate with a route then it means that the
>prune applies to a route rather than a source.

Yes.  That's how DVMRP works.

>But, if it is desired to prune traffic only from a particular
>source or set of sources in the network then this strategy will not
>work.

In this case, you use a 0xffffffff netmask to indicate this.

The valid values for the netmask field in the DVMRP Prune message are:
- The netmask associated with the route to the source, or
- 0xffffffff to indicate pruning only this single source.

  Bill