Ian King wrote:
"Near-perfect example"? I beg to differ. I used to work for a Local
The telephone number situation in the United States has been one of
continual crisis for years, because of rapid growth in use (in part because
of Internet access!). The area served by a given "area code" would be split
into smaller areas with multiple area codes; these days, those areas aren't
necessarily even contiguous. Moving from seven-digit to (effectively)
ten-digit numbers was difficult, if not impossible, for some older
equipment; sometimes a kludge could be developed to allow the old equipment
to be used for a few more months or years, but often as not new equipment
was required, at considerable cost. It was difficult for end users, too: in
addition to the confusion everyone suffered during the transition (I still
get scads of wrong numbers on my cellphone, because people forget the area
code is needed), businesses had to spend great sums of money to revise their
public appearance (advertising, letterhead, etc.).
And, often as not, we'd do it all over again a few months later.
We've now got number portability. I've got a choice of local exchange
carriers. I can get service from Bell Atlantic or from MediaOne. I can
keep the same phone number when I move from one to the other.
From the reports I read, this was implemented by mapping phone numbers
to some other tag (which the user doesn't see) which is used to get the
calls to the proper carrier and ultimately to the proper user.
Sounds a whole lot like using DNS to map names to IP addresses. Of
course we expose users to IP addresses WAY too often, and overuse them
in applications as well, for this analogy to be really workable for the
Users shouldn't care or know about the network's internal addressing.
Some of the application issues with NATs spring directly from this issue
(e.g. user of X-terminal setting display based on IP address instead of
Daniel Senie dts(_at_)senie(_dot_)com
Amaranth Networks Inc. http://www.amaranth.com