Yves Devillers <Yves.Devillers@inria.fr> writes: * * ==>Is there a place were one can fetch that marvellous tool able to do * automatic agregation in a relevant fashion ?
Tony Bates <Tony.Bates@ripe.net> writes:
I use a tool written by Bjorn Carlson to do this. Check out
ftp://ftp.ripe.net/cidr/tools/fixnets.c
I think that this tool will not create aggregates where there exists "holes" in the network numbers which are being routed (at least that was what I heard last time; I have not actually used or read the program). Such holes may be there because a site is temporarily unavailable, because the network number hasn't been assigned yet etc. I have yet to see a tool which beats human knowledge when it comes to determining which ranges can be announced as aggregates, especially when the knowledge of the assignment status for blocks is known. The output of such a tool should be taken mainly as "advice". I will claim that there is nothing dangerous and certainly very small inconvenience or cost involved in announcing such "holes" as part of a CIDR announcement. Remember that we do it all the time when it comes to non-assigned subnets of class B networks. Depending on your routing policy, there may be small complications when a customer moves to another service provider, but we all know that, right? Add to that that you'll be able to assign new networks to your cursomers and route them without having to modify your external announcements, and you have a nice savings in the form of less work to do. - Havard