[NNTP] LIST EXTENSIONS and an NNTPv2 capability

Clive D.W. Feather clive at demon.net
Tue Oct 26 09:20:03 PDT 2004


Ken Murchison said:
> I'm curious as to what makes NNTP so different from IMAP/POP/SMTP that 
> it requires an extension discovery mechanism that is orders of magnitude 
> more complex.  These other protocols have been able to "survive" with a 
> mechanism just as simple as the existing LIST EXTENSIONS + NNTPv2 
> proposal.  In fact, IMAP is far more complex than NNTP and is able to 
> get by with a very simple CAPABILITY command.

Firstly, I'm not sure that NNTP is significantly different (but see below).
However, I suspect that it's simply that none of them have run into the
problems I discuss *yet*. And SMTP *has* sort of had the versioning
problem, with the HELO v EHLO commands.

I also don't accept "orders of magnitude".

My concerns, as explained in my previous messages, split into two areas:

(1) The ability to handle variations - version numbers - of extensions.
This *will* happen to lots of protocols, even if it hasn't happened yet.

(2) NNTP's unique (as far as I know) concept of "extensions that aren't
available until you do something separate".

The two can be considered orthogonally. Each, if you accept it is an issue,
introduces a need for something more, though not as much more as you might
think.

> My fear is that we are trying to over engineer this to the point of 
> solving a non-existent problem.  I'm also afraid that this level of 
> complexity will lead to implementation delays or no implementations at all.

I went through my views in detailed steps. If you disagree with them, I'd
still like to know where; I think that will help move the discussion on.

> This is another case where we need client vendors to determine what is 
> necessary.  The only client feedback that I have seen is from Mark 
> Crispin, whose c-client library is used as the core of Pine (and other 
> packages like PHP) and supports all 4 protocols discussed above.  His 
> quote to me (he's not on the mailing list so he may or may not have 
> posts sitting in the moderator queue) regarding the STATUS proposal was 
> "It is unnecessary and needlessly complex.  It should not happen."

I'd like his feedback as well. I'm unconvinced of "unnecessary", but I'd
like to know where we diverge. As for "needlessly complex", all it does is
adds a version number and an "available or not" flag to each extension.
If these are needed, then it's pretty minimal. If not, then let's debate
why not.

-- 
Clive D.W. Feather  | Work:  <clive at demon.net>   | Tel:    +44 20 8495 6138
Internet Expert     | Home:  <clive at davros.org>  | Fax:    +44 870 051 9937
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Thus plc            |                            |



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