At 19:38 -0400 8/10/00, Fred Baker wrote:
At 01:33 PM 8/10/00 -0400, Corzine, Gordie wrote:
Wouldn't it be better by far, to assign new addresses from 000...1, and map
to routing information however we may code it?
well, that is essentially what has happened in the telephone network, at
least the wireless portion of it. Your telephone number is no longer
<country code><area code><exchange><house> but is essentially a random
number which is used to look up your E.214 IMSI in a database, find the
current topological location of the telephone, and then place a
circuit-switched route to it. You move, the route follows you.
What the Internet architecture tries to do is get rid of the
circuit-switched route and the large-scale database. We do that by
embedding topology information in the IP Address. This is fundamentally the
difference between a connection oriented and connectionless network.
No, it's not a stupid question. It's a paradigm question. You're asking the
same thing Dave Mills asked in the mid-1970's: are we better off with
circuit-switched routes or connectionless routes? Kleinrock's premise,
underlying packet networking as we know it, is that the latter is a winner
for survivability reasons. Those who form the bell-shaped side of the
business tend to be of the other opinion. This constitutes something of a
religious divide.
As to the difference between the two, you can think of it in terms of
telling someone how to get from Los Angeles California to Jacksonville
Beach Florida. There are three ways:
- I can give the guy a map and tell him to find his own way
(that may be Active Networking)
- I can tell him to get on Highway 10 and go east until he can't go any
further
- I can tell him to get on Highway 10, go east until he comes to a
junction,
and then ask someone for directions.
The first is pretty complex when you think in terms of packet networks. The
second is pretty simple, but gives the driver (packet) no options. The
third is more survivable, but requires enough intelligence in the driver to
ask the right question. The third is connectionless networking as
implemented in the IP Internet. The topological address is what he needs to
ask that question.
Next issue is "so how do we get the right address?" - aha, something that
you translate into a topological address for the purpose of routing is a
name. The ITU even has a formal definition somewhere that puts it in so
many words. We have names - DNS names.