On 12/02/2011 09:50, Ted Hardie wrote:
On Thu, Dec 1, 2011 at 11:08 PM, Doug Barton <dougb(_at_)dougbarton(_dot_)us
<mailto:dougb(_at_)dougbarton(_dot_)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.
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.
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