CIDR FAQ

Tony Li tli at cisco.com
Thu Aug 17 06:11:29 UTC 1995


Simon,

   >The exact source of this growth has not been determined quantitatively.

   Which somewhat explains why this group reminds me of a bunch of decapitated
   hens. 

We welcome folks who would like to study it in more detail.  We have a
surplus of folks interested in flaming, a shortage of those actually
interested in the problem (and I include both pro and con participants).

   Would it be correct to interpret your last sentence as:

	     We don't what the underlying cause of the growth in prefixes
	     is (new allocations, old allocations, ISP's not aggregating).

This is overly broad.  We have been doing periodic (but irregular!)
top-20 non-aggregating ISP reports which clearly show that there are
major gains to be had by certain ISP's aggregating.  Determining if a
particular prefix is the result of someone using an address in the
"portable" model is rather difficult as you have to understand their
motivation and plans, as well as just the routing data.  For example,
they may be in the process of doing the renumbering within the
organization and may quite legitimately be using multiple prefixes,
some from the old provider or a legacy allocation.

   With other words, we don't even know if the I-D in question is fixing the 
   right problem.

I think we have a small misunderstanding here.  Erik-Jan's figures as
presented in Stockholm are evidence that we still have a problem.  The
address ownership I-D is _not_ a direct response to that presentation.
In fact, the "ownership" presentation was first given in Danvers.
This is not cause and effect and I certainly didn't intend it as such.
I apologize if I was misleading.

To summarize:
	- We know we still have a bad problem.
	- We have end users who want "portable" addresses.
	- Some of them are actually getting them.
	- There are some ISP's who are not doing a reasonable job of
	  aggregation. 
	- We would like the ISP's to do a better job of aggregation.
	- "Portable" addresses, by definition, are not aggregateable.
	- If we can substantially reduce the number of "portable"
	  addresses which are assigned, then we can alleviate one
	  _clear_ cause of the problem.
	- Other measures are in place to encourage ISP's to aggregate.
	- Even more measures still remain to be developed.
	- Most of the Evil Greedy Bastards who espouse CIDR have done
	  a good job of aggregating already.

Tony



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