Subject: Re: RFC822's Appendix D, and X- fields

From: "D. J. Bernstein" <[email-masked]>
Date: 6 Feb 2000 20:43:15 -0000

Sam Roberts writes:
> And what about Appendix B, Simple Field Parsing, or is it deemed
> redundant?

Not at all. Any sensibly structured parser will start that way. See
http://cr.yp.to/immhf/header.html and http://cr.yp.to/immhf/field.html;
beware that there are several interoperability problems to watch out for
even in this ``simple'' format.

> I also was looking for a description of the X- for extension fields
> that will never conflict with the names of standard fields.

If you're trying to avoid conflicts, contribute to my list of names at
http://cr.yp.to/immhf/index.html. The X- prefix really doesn't help.

---Dan

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From: Charles Lindsey <[email-masked]>
Date: Sun, 6 Feb 2000 18:03:37 +0000 (GMT)

On Sat, 05 Feb 2000 14:38:36 -0500
	Keith Moore <[email-masked]> said...

> the problem isn't with the X- convention, it is with the idea that
> you can create a new field in isolation and not cause interoperability
> problems.  this problem exists whether or not you use the X- convention
> for your new field name.  the X- convention cannot solve the problem,
> but it can serve as a warning to others - don't expect this field 
> to be used consistently from one implementation to another.

I agree entirely. That is essentially what we are saying in the USEFOR draft.

Charles H. Lindsey ---------At Home, doing my own thing------------------------
Email:     [email-masked]  Web:   http://www.cs.man.ac.uk/~chl
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From: Dave Crocker <[email-masked]>
Date: Wed, 09 Feb 2000 08:00:46 +0100

At 03:38 PM 2/8/2000 -0500, Keith Moore wrote:
>what you call chilling effects and what I might call strategically
>placed bars are sometimes useful.  some people think that the IETF

1.  Sometimes is not always.  X- is always

2.  For all of your concern about examples, what are the examples of 
BENEFITS from the artificial X- barrier?

>process imposes a chilling effect because people have to meet
>certain requirements to get their work declared as standards.

This isn't about meeting standards.  Those requirements are well enforced 
through other mechanisms.  This is about ALWAYS requiring starting over, 
and therefore losing all install-base momentum.  Always.

In effect you are insisting on a syntactic barrier for enforcing a policy 
barrier.  Overloading functions that way should be permitted only in the 
face of compelling requirement and a good ability to demonstrate that the 
requirement needs to be enforced that way.

d/

=-=-=-=-=
Dave Crocker  <[email-masked]>
Brandenburg Consulting  <www.brandenburg.com>
Tel: +1.408.246.8253,  Fax: +1.408.273.6464
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From: Charles Lindsey <[email-masked]>
Date: Fri, 25 Feb 2000 09:20:17 +0000 (GMT)

On 24 Feb 2000 21:39:52 -0000
	"D. J. Bernstein" <[email-masked]> said...

> 
> 
> Charles Lindsey writes:
> > I think what I had in mind was to restrict it to those which had made it
> > into an RFC, with maybe a 'provisional' listing for those which had made
> > it into an internet-draft.
> 
> Great idea!
> 
> Let's allocate TCP port numbers the same way. IESG-approved protocols
> will be assigned ports. Private experiments won't be assigned ports;
> experimenters can simply pick ports in the 50000-65535 range.
> 
> Two experimenters might accidentally select the same port, you say? The
> users and implementors will suffer if both protocols become popular?

Which is why I carefully said there could be provisional listing for
internet drafts. If you have a bright idea, try it out first with an
X-Header, just to make sure it works. But if you want it to catch on
and become the de facto standard (in which case you care whether it is
unique or not), then write it up as an internet draft, at least for an
experimental protocol. There is nothing like being made to write your
idea down clearly on paper and having other people discuss it, when it
comes to getting the bugs and inconsistencies out of it.