On Thu, Dec 1, 2011 at 11:08 PM, Doug Barton <do...@dougbarton.us> 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. 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*. To retain those customers, the ISPs will simply ignore the RFC and use some other space. At least, that's my prediction. regards, Ted > > 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/ > >
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