ietf-822
[Top] [All Lists]

Re: mail vs. news ???

2003-02-22 14:12:15

"Dave" == Dave Crocker <dcrocker(_at_)brandenburg(_dot_)com> writes:

 AG> Mail systems do not appear to make any actual use of the
 AG> message-id header other than for logging (and internally in some
 AG> odd systems).  None of SMTP, POP3 or IMAP ever use message-ids as
 AG> protocol parameters.

 Dave> Message-ids are not nearly as deeply and usefully and broadly
 Dave> used as we had expected them to be.  However, they ARE used, to
 Dave> good effect, for duplicate detection and for thread
 Dave> construction.

at the layer of actual message transport, or just in the clients or
client-side services such as IMAP threading? I really wasn't referring
to the clients when I mentioned "mail systems".

I have heard of mail transports that assume a 1-1 correspondence
between message-ids and body content but I believe this to be highly
unusual; please correct me if I am mistaken on this point.

There is absolutely no comparison between the extent to which
message-ids are used in mail and the extent to which they are used in
news. Their importance to the news transport is _in addition to_ uses
such as threading which are common with mail. Duplicate detection is
not something which is optionally performed by clients or user
delivery agents but something which is built right into the core of
the system. Every news server, regardless of the type of transport it
uses, has to keep a database of message-ids seen. A fullfeed transit
server with a lot of peers might receive over 200 million CHECK
commands per day (that's over 2300 per second), all containing a
message-id that must be looked up in the local history database. Some
news clients use the fetch-by-message-id commands of NNTP for _all_
their article retrieval. All NNTP article retrievals, whether by ID or
number, contain the message-id of the retrieved article in the command
response. And so on.

-- 
Andrew.

<Prev in Thread] Current Thread [Next in Thread>