Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!uunet!mcvax!ukc!dcl-cs!aber-cs!pcg
From: pcg@aber-cs.UUCP (Piercarlo Grandi)
Newsgroups: comp.mail.sendmail
Subject: Re: Short-circuiting a route
Keywords: sendmail, smail, domain names
Message-ID: <1040@aber-cs.UUCP>
Date: 29 Jun 89 11:29:21 GMT
Reply-To: pcg@cs.aber.ac.uk (Piercarlo Grandi)
Organization: Dept of CS, UCW Aberystwyth
	(Disclaimer: my statements are purely personal)
Lines: 28

In article <3570@ncar.ucar.edu> woods@handies.UCAR.EDU (Greg Woods) writes:
    In article <4140@tank.uchicago.edu> matt@oddjob.uchicago.edu (Matt Crawford) writes:
    
    >But in the absence of such cooperation, what I did was to short-circuit
    >only if the first hop was not a known UUCP neighbor.  
    
      THANKS! I guess I can mark oddjob as undead now? I see nothing wrong with
    doing this, because there would be no way for you to deliver the message 
    otherwise.

Actually you have more freedom than this; you can *always* add components to
the *beginning* of a route, even if its first component is directly attached
to you (e.g. if the direct link is slow or temporarily dead and the sender's
maps have not been updated yet). On the other hand, every site should only
add the minimum number of components to the beginning of a route.

If everybody stuck to this rule, one could have a full spectrum between
source routing and aggressive (dynamic) routing; if you want the former,
just specify the full route, if you want the latter just specify the first
hop (and rely on it and every other hop to keep specifying only the hop and
target) and the target (in UUCP this, to be unambiguous, may need to be a
relative name, i.e. a route... :->), if you want in between, specify
a few hops between you and the target, and let them figure out the routes
among themselves.
-- 
Piercarlo "Peter" Grandi           | ARPA: pcg%cs.aber.ac.uk@nsfnet-relay.ac.uk
Dept of CS, UCW Aberystwyth        | UUCP: ...!mcvax!ukc!aber-cs!pcg
Penglais, Aberystwyth SY23 3BZ, UK | INET: pcg@cs.aber.ac.uk