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.
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.
Doug
--
"We could put the whole Internet into a book."
"Too practical."
Breadth of IT experience, and depth of knowledge in the DNS.
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