Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 6/24/83 (MC830919); site haring.UUCP
Path: utzoo!linus!decvax!mcvax!haring!teus
From: teus@haring.UUCP
Newsgroups: net.mail
Subject: Re: Area-code as uucp domains
Message-ID: <203@haring.UUCP>
Date: Tue, 21-Feb-84 11:39:14 EST
Article-I.D.: haring.203
Posted: Tue Feb 21 11:39:14 1984
Date-Received: Wed, 22-Feb-84 04:36:15 EST
References: <426@psuvax.UUCP>, <758@ulysses.UUCP>, <3508@utzoo.UUCP> <3513@utzoo.UUCP>
Organization: CWI, Amsterdam
Lines: 79
Apparently-To: rnews@mcvax.LOCAL

"The domain-based system decouples naming and routing almost completely,
and it is important to make the distinction." (Henry Spencer).

That is already discovered by the PTT.
People are already using domain addressing schemes for some time
now. As well they use routing. To deliver an envelope with data
domain addressing is used in the address and routing is used for delivering
or better to carry the packet from mr Mark to mrs Karin.

Insite the building the address of the packet sent by Mark is just "Karin".
The postman has some intelligence insite the building so he knows
to route the packet to Karin. The default domain in this case is just
the building. Even the postman needs not to know the name of the building
now. However if Karin is living in another building on the campus, Mark
needs to include more to the address on his packet to Karin.
He can use the sub-domain "Building 1C" in his address. 
So in this case Mark is living in "Building 2C" and
Karin's address is "Karin in subdomain Building 1C".
Both are on the campus say domain "Bell". 
The packet with the address Karin@Building1C is given to the postman in
Marks building (2C), he does not know the route now, but knows that the
postman in Building 1C knows all the details there and 
will route the packet to the subdomain Building 1C on the campus "Bell". 
That is not an easy job for him. Now he needs to think. 
Well he knows some of the friendly speedy postmen at that subdomain.
So he routes the packet to a postman out there, which he trust most.
And the packet will arrive at Karin's desk via that postman some time later.

Well I'm living somewhere else in the world. So if I need to send a mail
to Karin, I have to include more data about the domains (boundaries) 
the packet is crossing. 
All the postmen on each domain level will have a hint (or handle)
to use their intelligence for finding a postman in each domain,
who can do the rest.

The postman in Building 2C from Mark does not need to know the route/path
to Karin. Even he does not need to know the existance of Karin at all.
Or the postman at my site (where I'm living) does not need to know
that there is a subdomain Building 1C insite the campus Bell or perhaps
that there is a Bell in the USA. The postmen in my top domain are the one
who really should know a route to one of the postmen in the domain USA!
Or if he knows a postmen at "Bell", well he can route the mail to him.

Or there is of course the possibility that my postman does not have that
intelligence. Well I can help him. If I know better I can 
provide him with a path/route to a postman which knows there. 
I.e. I give him the route to f.i. the postman in
Building 2C (Marks postman) or f.i. to Mark himself.

Conclusion:
Only the postman on level n needs to know (is up to date) about one of
the postmen on level n-1. If he is more intelligent (knows more details
of levels < n-1) well that is nice. What he does is routing it to some
postman on a level < n.
So if someone new or some new postman is added only the postman (or better
postmen) in that domain need to know that. If a new subdomain is added
only the postmen one level higher need to know that.
The only appointments to be taken is the format.
(see <3508@utzoo.UUCP>, Lauren).

I agree with Lauren that there is no need to map domains or subdomains
on anything particular (f.i. geographic), but it can help. So "decvax"
is ok (it has nothing to do any more with some machine at DEC!) and
"NJ" is ok. The PTT is using some number scheme. Well that is for people,
machines can handle names very easy. And it is easier for me to remember.

The scheme as above will leave everybody free. A full path is still
possible (but who will use that?), intelligence is used where possible,
combinations of routing and domaining can be used. Even John Gilmore
can hide his 50 machines inside the SUN domain (but should announce
his postman machine to the California domain postman ucbvax).
F.i. erix!enea!mcvax!philabs!cbosgd!mark (a full path),
erix!enea!mcvax!mark@Bell.OH.USA.UUCP (a mixure),
mark@cbosgd.Bell.OH.USA.UUCP (on domains) are the same.
Forgiveness for the format, I just picked one which is suppost to be
clear for everyone.

-- 
	Teus Hagen	teus@mcvax.UUCP  (CWI, Amsterdam)