[I've taken the bulk of my response to Ed's last reply to private
mail, since I assume few here are interested in tedious arguments
about exactly how the Internet is analogous to the postal system,
but I'll just make his one public observation:]
At 9:45 PM -0800 2/15/01, Ed Gerck wrote:
I agree that you can define many different analogies, from that example.
But, as above, if you consider the way that information is received then
a NAT box is IMO one valid analogy for reception because it satisfies
the functionality observed in a NAT box when receiving packets.
Your postal example doesn't entail the modification of an address on
the received package, which is the defining characteristic of a NAT.
Your postal analogy does show how you can get nice properties of
address portability and location-hiding within a local network
*without* resorting to address modification, i.e., it shows that
you can have the flexibility you so prize without doing NAT. Maybe
that's the lesson you should draw from this "naturally occurring"
analog to packet networks.