nanog mailing list archives

Re: Mac OS X 10.7, still no DHCPv6


From: Owen DeLong <owen () delong com>
Date: Mon, 28 Feb 2011 16:00:16 -0800

Small (say, under 50,000 customer) ISPs in my experience have a planning horizon which is less than five years from 
now. Anything further out than that is not "foreseeable" in the sense that I meant it. I have much less first-hand 
experience with large, carrier-sized ISPs and what I have is a decade old, so perhaps the small ISP experience is not 
universal, but I'd be somewhat surprised giving the velocity of the target and what I perceive as substantial inertia 
in carrier-sized ISPs whether there's much practical difference.

Ready or not, IPv6-only (or reasonably IPv6-only) residential customers are less than 2 years out, so, well within
your 5-year planning horizon, whether those ISPs see that or not. Denial is an impressive human phenomenon.

So, what's a reasonable target for the next five years?

In five years we should be just about ready to start deprecating IPv4, if not already beginning to do so.

1. Deployed dual-stack access which interact nicely with consumer CPEs and electronics, the IPv4 side of the stack 
deployed through increased use of NAT when ISPs run out of numbers.

Icky, but, probably necessary for some fraction of users. Ideally, we try to avoid these multi-NAT areas being
done in such a way that the end user in question doesn't also have reasonably clean IPv6 connectivity.

2. IPv6-only access, CPE and hosts, with some kind of transition mechanism to deliver v4-only content (from content 
providers and v4-only peers) to the v6-only customers.

This is, IMHO, preferable to option 1.

Perhaps it's because I've never seen a NAT-PT replacement that was any prettier than NAT-PT, but I don't see (2) 
being anything that a residential customer would buy before 2016. Perhaps I'm wrong, but I don't hear a lot of people 
shouting about their success.

Personally, I think DS-Lite is the cleanest solution, but, it isn't without its issues. The reality is that post-runout
IPv4 is going to be ugly, regardless of whether it's NAT64 ugliness, LSN ugliness, or DS-LITE ugliness.

IPv4 is all about which flavor of bitter you prefer at this point. The sweetness is all on IPv6.

Note, I'm not talking about the ISPs who have already invested time, capex and opex in deploying dual-stack 
environments. I'm talking about what I see as the majority of the problem space, namely ISPs who have not.

The majority of the problem space IMHO is end-user-space at ISPs that have put at least some dual-stack
research effort in, but, haven't come to solutions for end-users.

However, we're less than 2 years away from seeing what happens in those environments without IPv4.

Owen



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