From: Simon Perreault [mailto:simon(_dot_)perreault(_at_)viagenie(_dot_)ca]
Sent: Saturday, July 07, 2012 5:21 PM
Wes,
Here's my take on this...
CGN as defined in this document does not only include NAT444. It is more
generic than that: it really means "multi-user NAT". Dave Thaler came up
with the example use case of the NAT in a wifi hotspot. It's just NAT44,
but it still fits with the draft's definition of CGN because you have
multiple users potentially fighting for the same NAT resources. Remember
that the main raison d'être of this draft is for the operator to be able
to ensure fairness between NAT users. So in this view I think it is
clearly behave material since the sunsetting of IPv4 really is
orthogonal to multi-user NATs.
On the question of IPv6: I don't think we should talk about IPv6 simply
because IPv6 NAT so far has not seen significant deployment in the
context of multi-user NAT. And NPTv6 is stateless so there are no
resources to fight for.
[WEG] I agree with all of what you've said, but I think I need to make the
point that I'm concerned with clearer, because the above doesn't exactly
address it. I wasn't saying anything about IPv6 NAT, or even IPv4 sunset. I was
saying that the current wording is unclear as to what you mean by "IPv4-only".
While the NAT specified by this document itself may only act on IPv4 traffic,
as you note above it's not limited to just NAT444 or even an IPv4-only
*network*. The recommendations in this doc will work for an IPv4 NAT associated
with DSLite just as easily as a more traditional IPv4 transport. This is an
important distinction, IMO.
Back to your email, where you wrote:
if it is truly a IPv4-only NAT (NAT44 or NAT444) requirements doc
rather than a more generic CGN requirements doc, it should be named to
reflect that.
How about "Common Requirements for IPv4 Carrier Grade NATs (CGNs)"?
[WEG] This helps, but only in conjunction with additional clarification about
the application - that is, just because the NAT is IPv4-only doesn't mean that
the network must also be IPv4-only.
Thanks
Wes George
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