--On Thursday, 15 February, 2001 16:36 -0800 "Bernard D. Aboba"
anyway, what's the half-life of a piece of network equipment?
In the consumer space, it's probably the life of the
customer's arrangement with the service provider. While
turnover is high with dialup ISPs, it is presumably lower
with xDSL and Cable modems. So I would be looking at more
like 4-5 year lifetimes (roughly equal to a PC) without
upgrading the NAT code load (which means that even if IPv6
native support were available, most customers would not do
Although, FWIW, there is some, possibly growing, tendency to
treat the CPE xDSL and Cable modems as being on the ISP side of
the demarcation point. That, of course, parallels the decisions
a number of ISPs made some time ago about customer-side edge
routers in order to improve the ISPs' ability to manage their
networks and provide improved service. Then, to the extent that
those boxes can be reprogrammed (or flashed) from the ISP side,
making code changes would not require customers to change
equipment or to actively engage in upgrade activities.
existing NATs are going to be discarded, or at least
upgraded, within a short time anyway.
I wish that were true -- but in the consumer space, people
just aren't very interested in futzing with network equipment
unless their provider tells them to. So it is more realistic
to assume that equipment stays in place for a substantial
Modulo the above, I agree with this. And "their provider tells
them to" is likely to be a rare event: I would imagine that at
least some providers would be concerned that some users would
respond by seeking providers who would issue such
aggravation-causing instructions less frequently.
Today, NAT penetration among consumers isn't very high because
networked multi-PC homes are relatively rare. However, as
multiple device homes proliferate along with home networking,
I would expect the majority of consumer PCs to be behind NATs
We should not underestimate the complexity of the policy
interactions behind this one. If an xDSL or cable provider says
"with your connection, you get enough IP addresses to set up a
reasonable house, you can get more if you need them, and we will
program the 'modem' will do the routing", then that provider's
customers are unlikely to rapidly increase the number of NATs.
If, by contrast, the provider says "you get one address; if you
think you need more, you are a commercial customer and we will
charge you 10 times as much", then almost every household with
two or more devices in it is going to end up behind a NAT. And,
of course, the causes of those ISP statements recurse to the
ISP's provider, etc., until one gets to PI space, and then to
RIR policies and strategies for home networking.
Worse, one can imagine xDSL or cable ISPs adopting
address-restrictive policies for management or economic reasons
completely unrelated to the availability of address space to
And IPv6 is, or is not, a solution depending precisely on those
choices of policies.