Path: utzoo!attcan!uunet!lll-winken!lll-lcc!ames!elroy!judy!stevo
From: stevo@judy.Jpl.Nasa.Gov (Steve Groom)
Newsgroups: news.software.b
Subject: Grading of UUCP news traffic
Keywords: Different UUCP grades for articles vs control messages?
Message-ID: <7182@elroy.Jpl.Nasa.Gov>
Date: 30 Jun 88 21:18:15 GMT
Sender: uucp@elroy.Jpl.Nasa.Gov
Reply-To: stevo@elroy.Jpl.Nasa.Gov (Steve Groom)
Organization: Image Analysis Systems Grp, JPL
Lines: 67

We have been slowly adding Trailblazer news feeds using ihave/sendme.
However, for some sites we deal with (including us), 'blazer time can
be hard to come by.  You know, several modems available, but the
'blazers are busy or just not available at all hours.

What we do now is put a grade limitation on the slower modems so that
it doesn't try to send news over a slow line if the 'blazer(s) is/are
busy, but holds news waiting for the 'blazer.  What I would like to do
is be able to send news control messages across the slow lines, and
just reserve actual article traffic for the 'blazers.

(For those of you unfamiliar with 4.3 BSD UUCP grading: for UUCP
commands such as uux you can specify a 'grade'.  Then in the L.sys
file, along with the time-to-call information, you can specify the
minimum grade permissible for jobs when connecting on that line.  Jobs
not qualifying remain queued and are not run until the line grade
allows it.  By putting mail at a different grade from news and setting
the minimum grade for a slow line somewhere in between the two, you can
restrict a line to mail only.)

Since we run ihave/sendme, I would like to be able to get those ihave's
and sendme's out to the other system as soon as possible, and at the
same time not worry about having news flow over slow lines.  This
would, I believe, make the protocol more effective, as timely replies
help reduce redundant traffic.  It would also help ensure that the
sender had articles ready to go when the fast line does become
available, and time wouldn't be wasted with the exchange and processing
of ihave's and sendme's during that time.

Doing something like this might also help improve the effectiveness of
cancel messages, by allowing them to propogate at a higher "priority"
than the regular message.

One drawback to giving all control messages a higher priority (that
you've probably already thought of) is that "sendsys" messages could
also flood the net that much faster.

(Note: we're running news 2.11 patch 14)

The mechanism I would propose to implement this would be to use
different UUCP grades for control messages and article batches.  Since
news uses the same uux flags (which include the UUCP grade
specification) for everything it sends, setting this up requires more
than just a header fix and recompile.  (Actually, the flags are
specified once in the 'localize' script and copied everywhere else during
the install.)

The quick solution would be to fix sendbatch and inews (actually
defs.h) directly after localize had been run.  Sendbatch invokes uux to
send articles and inews invokes uux to send control messages, so I
think that would allow a 'control message' grade and an 'article batch'
grade.

An extravagant solution might be to set up the software with several
different sets of uux flags which could be specified from 'localize',
with perhaps a different set of flags for each type of control message,
and another for article batches.  I'm sure that, in practice, this
would be overkill.

I would like to hear what others think about this.  I will be hacking a
bit locally for my own purposes, but I thought that this might be of
general interest and a possibility for inclusion in later releases.

-steve
/* Steve Groom, MS 168-522, Jet Propulsion Laboratory, Pasadena, CA 91109
 * Internet: stevo@elroy.jpl.nasa.gov   UUCP: {ames,cit-vax}!elroy!stevo
 * Disclaimer: (thick German accent) "I know noothingg! Noothingg!"
 */