Path: utzoo!lsuc!ncrcan!ontenv!soley
From: soley@ontenv.UUCP (Norman S. Soley)
Newsgroups: news.admin
Subject: Re: No longer about April Fools (the Path: header)
Message-ID: <442@ontenv.UUCP>
Date: 6 Apr 88 17:11:54 GMT
References: <1590@sigma.UUCP> <4750002@hpscdc.HP.COM> <47838@sun.uucp> <5137@ihlpg.ATT.COM>
Organization: Ontario Ministry of the Environment, Toronto
Lines: 68

In article <5137@ihlpg.ATT.COM>, ejbjr@ihlpg.ATT.COM (Branagan) writes:
: So far, so good.  Message IDs and history indeed are sufficient to
: prevent loops.  They are also NECESSARY to prevent duplication of
: articles recieved from multiple independent paths through the
: network.
: >				They aren't sufficient to prevent
: > wasted transmissions of articles;
: This however is not true.  Rather than checking the Path:, it would
: be possible to ask the remote machine if it already has a given
: message ID in its history file BEFORE transmission, rather than
: waiting to check locally on the remote machine after transmission.

Doesn't this already exist in the form of ihave/sendme?
  
: This would be perfectly sufficient to prevent retransmission of
: articles back and forth between machines.
  
Yes but at what cost, There are two costs to maintaining a link; the
time required to transmit your data and the time the line sits idle
while you process things. Requiring history checking will reduce the
first no doubt but would also certianly increase the idle time. 
  
: It would also prevent the tremendous amount of wasted transmission
: of articles by multiple paths through the network for which the Path:
: header is not sufficient.

When is this the case? I know the Path: line can mess you up if your
name is a subset of someone elses but barring that when does Path:
break down?
  
: >				    getting rid of Path: will
: > significantly increase backbone news traffic (adding roughly one
: > full feed's worth of traffic), since every backbone site talks to at
: > least two others and passes full feeds back and forth.
: Only if article transmission continues to ignore the existence of
: history (i.e. eliminating Path: WITHOUT adding a history check
: would significantly increase network traffic.  Eliminating Path:
: and using history instead would DECREASE network traffic).
: So why don't we use history instead?
  
See above, traffic decreases but connect time (i.e. what the phone
company charges us for) increases.

: Before I stick my foot too far down my throat, does such a protocall
: already exist?  Based on my limited knowledge of netnews internals
: and the discussion I've seen here, I don't think so.  If it does,
: could someone more knowledgable tell us about it?  If it does exist,
: is it limited to major backbone sights? - if so should it be more
: widely distributed?

Ihave/Sendme does this and it's a part of regular netnews if you turn
it on. Personally I only take news from 1 feed so I don't have a
multi-path problem. I don't know how extensively Ihave/Sendme is used
in the more connected part of the net.

: Note that the Path: header would still be needed - as an audit trail to
: track down problems like sites which mangle headers.  It would be nice
: if the Path: header were more hidden though, to prevent attempted 
: misuse.

And the INTERNET define should be....OK so that's another war...I'll
shut up about it. 

-- 
Norman Soley - Data Communications Analyst - Ontario Ministry of the Environment
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