[news.software.b] Multicast batching, anyone?

flee@shire.cs.psu.edu (Felix Lee) (05/04/89)

Has anyone used the multicast feature to batch news?  I was thinking
of compressed batches.  Multicast batching could reduce compression
overhead significantly.  Something like, a multicast target that
batches the standard news subscription to multiple hosts, and other
targets for regional and non-standard subscriptions.  Non-overlapping
subscription classes may be a little tricky because of the confusion
between hierarchies and distributions...
--
Felix Lee	flee@shire.cs.psu.edu	*!psuvax1!shire!flee

eric@snark.uu.net (Eric S. Raymond) (05/06/89)

In <FLEE.89May3160952@shire.cs.psu.edu> Felix Lee wrote:
> Has anyone used the multicast feature to batch news?  I was thinking
> of compressed batches.  Multicast batching could reduce compression
> overhead significantly.

In TMN-Netnews multicast is handled in a way designed to make this easy.
Basically it goes like this:

In the feeds file (the old sys file) the target system name field may contain
a comma-separated list of systems. Normally, such an entry behaves exactly as
several duplicate entries (one for each system) would.

However, if the entry includes the 'X' multicast flag, the list of systems is
treated as a multicast group. If no explicit transmission command is given in
the entry, UUCP multicasting using Shane McCarron's uucast code is done. If
there *is* an explicit transmission command, the whole system list is passed
to it as an argument (this is a hook for hypothetical future multicast
networking methods).

This is orthogonal to the batching options. So if you have batching set on a
multicast group you should get exactly the result you want -- one batch
generated, with multicast xmit to the target systems. This is the case I
had in mind when I designed the feature.

And yes, this is all documented in the installation guide.

Warning: the multicast code has been exercised in debug mode but not live-
tested yet, it's a recent addition. It's very simple though, I'm confident
that it will work fine.
-- 
      Eric S. Raymond                      (the mad mastermind of TMN-Netnews)
      UUCP: {uunet!vu-vlsi!cbmvax}!snark!eric      INTERNET: eric@snark.uu.net
      Post: 22 S. Warren Avenue, Malvern PA 19355  Phone: (215)-296-5718

mark@jhereg.Jhereg.MN.ORG (Mark H. Colburn) (05/07/89)

In article <1RMF4D#9rtBZh=eric@snark.uu.net> eric@snark.uu.net (Eric S. Raymond) writes:
>In <FLEE.89May3160952@shire.cs.psu.edu> Felix Lee wrote:
>> Has anyone used the multicast feature to batch news?  I was thinking
>> of compressed batches.  Multicast batching could reduce compression
>> overhead significantly.

Most of the sites in the state of Minnesota have used a version of
multicasting which was developed by Steve McDowell and Shane McCarron.  The
software works with the existing 2.11 new software and does multicasting
quite simply.  It supports both vanilla and HDB UUCP.

If there is enough interest, I can post the software...

-- 
Mark H. Colburn                          mark@jhereg.mn.org
Minnetech Consulting, Inc.