ietf-nntp New wording on article numbers - draft 3

Jack De Winter jack at wildbear.on.ca
Sat Jan 11 11:42:43 PST 1997


>Consider a "master" server, which receives and sends ordinary news feeds
>to one or more peers, just like an ordinary news server.
>
>Consider a "slave" server which wishes to use the same article numbers
>as the master server.  To this end, the slave receives a news feed from
>the master, but does not receive a feed from any other news system.  The
>slave learns the article numbers that the master has used (either by
>looking at Xref headers, or via a protocol extension such as xreplic),
>and the slave then uses the same article numbers as the master.

Well, I guess that for this, we would need to make sure that 1036
defines proper XRef headers and that if XReplic is in wide use, that
it is in the 997bis doc....

>If the feed from master to slave consists of a single NNTP session, then
>articles from the master to the slave will usually be transmitted in
>order, and there is no problem.  But in practice articles do sometimes
>get out of order.  For example, a temporary failure could result in
>article 12 being transmitted successfully, article 13 failing and being
>written to a backlog file to be tried again later, and article 14 being
>transmitted successfully.

I guess there is the question then about whether this is considered
'backfill' or a form of reinstatement.  Why would you be able to get
14 and not the others though?  I would have tried to get 14 again.

>If the feed from master to slave includes several parallel connections,
>then articles 12 and 13 might be transmitted over different connections,
>and might arrive out of order, even in the absence of any temporary
>failures.  Guaranteeing that all articles in a particular newsgroup are
>transmitted over the same connection is infeasible in the face of
>crossposted articles.

In a parallel mode I can see this.  However, if you know that you feed
is a replicating feed, I would stick to the wording in the current
numbering system.  In the case of replicating, if you know that 12 and
13 should be there and 14 has arrived, then don't expose #14 until you
know that 12 and 13 are there... then it isn't considered backfill.

>> (the hard point with doing pure theoretics is that we don't always
>> think of applications right off the bat... sharing the applications
>> can help make the theory a lot easier)
>
>I hope this helps.

yup.... the world for an example...

regards,
Jack
-------------------------------------------------
Jack De Winter - Wildbear Consulting, Inc.
(519) 576-3873		http://www.wildbear.on.ca/

Author of SLMail(95/NT) (http://www.seattlelab.com/) and other great products.



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