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Path: utzoo!linus!decvax!ucbvax!kre
From: kre@ucbvax.ARPA (Robert Elz)
Newsgroups: net.mail
Subject: Re: Name space explosion -- first tremors
Message-ID: <9390@ucbvax.ARPA>
Date: Sat, 27-Jul-85 07:51:49 EDT
Article-I.D.: ucbvax.9390
Posted: Sat Jul 27 07:51:49 1985
Date-Received: Sun, 28-Jul-85 06:03:10 EDT
References: <568@decuac.UUCP> <531@down.FUN> <570@decuac.UUCP> <537@down.FUN>
Organization: University of California at Berkeley
Lines: 64
Summary: down!honey's scheme looks attractive, but has drawbacks ...

In <537@down.FUN> Peter Honeyman made a fairly persuasive case
for not using domains, but for using uucp style addresses instead,
with a smart parser to work out what where you wanted your mail to
go, and find a route to get there.

One problem with this is ambiguous names - two sites with the same
name.  Peter's solution to that is to (rightly) notice that in
that case, just giving the name is insufficient, you have to
provide more information.  The extra information that he suggests
is the name of a uucp neighbour of the badly named site.  This
works, as no site can talk to two others of the same name.

The problem with this "solution", is that addresses aren't anything
that can be relied on.  Peter's address in his scheme would be
"down!honey".  Today.  Tomorrow it might not be, as anyone,
anywhere can create another "down", making "down!honey" ambiguous.
Peter's address is now "princeton!down!honey".  I'm not sure
how anyone could explain to users that the unrelated actions
of some site on the other side of the world, on some unrelated
network (Peter's scheme has lots of networks rolled into it)
has suddenly invalidated what used to be a perfectly good address.

Of course, things don't end there.  All that needs to be done now
is to make another node "princeton" and connect it to the new "down"
and Peter's address changes again.  Now it is "seismo!princeton!down"
or "seimens!princeton!down" or any of dozens more.  Apart from the
original name change, we now have the problem that Peter has
lots of different addresses, and it takes a very smart piece of
code to deduce that they all specify the same person.

The final straw is that none of these nodes actually need to
exist - all I need to do to foul up lots of people's mail to
Peter, if I feel unkind to him, is to add dozens of dummy hosts
to my route maps, connected just the same way that they are
in real life.  It would be possible to set things up so that
just about the only legal address for Peter would be a fully
specified uucp path (just like we used to have to use, and
many places still do).  Somehow i can't believe that this
is a practical solution

This is the principal difference with domains.  A domain is
an *authority*.  That is, there is some responsible entity
who alone can make new names in the domain.  Peter's scheme
assumes mutual cooperation, which in some environments can
be assumed, but can't be in others.  In a mail system that
you want to work everywhere, you simply have to allow for the
bastards (like me) as well as the good guys (like Peter).

Don't be misled by syntax trivia - it makes no difference
whether domain names are expressed
	cbosgd.att.uucp!mark
or
	uucp!att!cbosgd!mark
or even
	mark@cbosgd.att.uucp

What's important is the issue of who is allowed to create
new names that are expected to be recognised in other places.

Some kind of naming authority is essential if this network
is to continue to grow and be useful.  That's exactly what
a domain is (and a domain is no more than that).

Robert Elz				ucbvax!kre