number of unaggregated class C's in swamp?

Michael Dillon michael at
Sat Sep 30 06:00:59 UTC 1995

On Fri, 29 Sep 1995, Dennis Ferguson wrote:

> I like the idea of measuring each and every class-A-sized block
> against some standard separately, since a lot of the class-C space has
> been allocated to regional registries this way and it inconveniences
> those places which have done the best the least.  I'm less attached to
> the number 1200 in particular, but I do think an explicit target should
> be chosen which represents both a tractable limit to design big routers for
> and which allows the implementation of efficient address allocation strategies
> which won't have to be tighened over time.  I do note that 1200 is
> close to the threatened /18 address filter, but this is mostly accidental.
> I'd much rather see each space filled with /14's and /20's, and even
> an occasional /23 or /25, as appropriate and as long as the filled block
> was only 1200 (or N, for some well-defined N) routes, rather than
> picking an arbitrary, one-size-fits-all filter limit.  The latter is
> a sign of failure.

Your N-routes-per-/8 block is less of a big-stick approach than the /18 
filtering and meshes well with what seems to be a movement to force 
people to renumber in that it provides an out for people who feel they 
must have an independently routed /24. If their provider can fit them in 
and still meet the goal of N in their block then it's OK. If they can't 
be fitted in, then they are not S.O.L. By renumbering to a different /8 
block they could still be allowed to keep their independently routed /24

Given that some people might feel threatened by the big stick approach it 
would be good to have an out for them so they don't feel cornered and run 
to their lawyers.

If there is a forced renumbering then would there also be some 
reallocation of these /8 blocks based on topology? Would a proportional 
fraction of N also be allocated to the providers who do the topological 
aggregation in each /8 block? So if N = 1200 and 4 providers are given
one quarter of a /8 like 192 would they also be given one quarter of the 
routes, i.e. 300, and then negotiate from there? Or is this whole idea of 
reassigning a block like 192/8 to NSP's based on topology completely 

Michael Dillon                                    Voice: +1-604-546-8022
Memra Software Inc.                                 Fax: +1-604-542-4130                             E-mail: michael at

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