On 12/02/2011 09:50, Ted Hardie wrote: > On Thu, Dec 1, 2011 at 11:08 PM, Doug Barton <dougb@xxxxxxxxxxxxx > <mailto:dougb@xxxxxxxxxxxxx>> wrote: > > On 12/01/2011 22:07, Ted Hardie wrote: > > No, I think that premise is mis-stated. Premise 1: There exists > > equipment that can't handle identical addresses on the interior and > > exterior interface. Premise 2: it may be deployed now or in the > future > > for customers using any part of the RFC 1918 allocation *because those > > using the RFC 1918 allocations had no prior warning that this might > > create a collision*. Conclusion: You cannot avoid identical > addresses > > on the interior and exterior interface by using any part of the > RFC 1918 > > allocation. > > But doesn't that same line of reasoning apply to any new allocation > that's made for this purpose? You can fix the problem for today, but you > can't fix it for the future because you can't prohibit customers from > using the new allocation on the inside of their network. > > > If a customer uses a CGN-specific allocation on the inside of their > network as if it were RFC 1918 space, then, yes, they will have trouble > if they ever use a provider that uses a CGN. Thanks. So my point is, this proposed allocation doesn't solve anything, it just kicks the can down the road a while. That's not enough benefit to justify the cost. > At the very least, though, > they have collaborated in their need to renumber by ignoring the quite > plain warnings that this is a bad idea. They did not have that warning > about using an allocation from RFC 1918 space. > > > > Therefore, making the allocation is a pointless waste of resources that > can be better utilized elsewhere. > > Step 1: Determine the most popular inside prefixes for CPEs > Step 2: Use the least popular RFC 1918 prefix for the CGN network > Step 3: If your customer has somehow chosen the same prefix, tell them > they can't do that. > > And yes, I realize that Step 3 is going to be incredibly unpopular for > the ISPs, but they created the problem, so they should have to live with > the results. > > > It's not going to be unpopular with ISPs, it will be unpopular with > *customers*. ... which is why it'll be unpopular with the ISPs. See what I did there? :) > To retain those customers, the ISPs will simply ignore the > RFC and use some other space. At least, that's my prediction. Works for me. Doug -- "We could put the whole Internet into a book." "Too practical." Breadth of IT experience, and depth of knowledge in the DNS. Yours for the right price. :) http://SupersetSolutions.com/ _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf