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Re: 2119bis

2011-08-30 10:45:07

On Aug 30, 2011, at 11:38 AM, Marc Petit-Huguenin wrote:

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On 08/30/2011 07:58 AM, Keith Moore wrote:
On Aug 30, 2011, at 10:54 AM, Marc Petit-Huguenin wrote:

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On 08/30/2011 07:35 AM, Keith Moore wrote:
On Aug 30, 2011, at 10:14 AM, Marc Petit-Huguenin wrote:

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On 08/30/2011 06:54 AM, Keith Moore wrote:
I think you're overgeneralizing.  My experience is that judicious use of
SHOULD seems to make both protocols and protocol specifications simpler;
trying to nail everything down makes them more complex.

But using SHOULD does not make the implementation less complex, it simply
decreases the complexity for the *author* and increases the probability 
that two
independent implementations will have interoperability problems.

To the extent that SHOULD is causing interoperability problems, it may be 
that some authors are misusing SHOULD.  But it's not an inherent problem 
with SHOULD.

As an implementer, I would ban all SHOULD/SHOULD NOT/RECOMMENDED/NOT 
RECOMMENDED.

I'm an implementor also, and I've found SHOULD to be very helpful.  

Yes, it is very helpful in convincing one's PHB that one does not have to
implement something, or in convincing another company to reactivate a 
feature
during interop tests because one did not bother to implement it.


Rather than vaguely attacking SHOULD, maybe it would be more illuminating to 
cite specific examples?

It is difficult because of a mix of NDAs, employment confidentiality 
agreements
and desire to not single out individuals.  I'll send you an example in a 
private
email.

I look forward to seeing it.

But in general I get the impression that people are attacking SHOULD because of 
specific problems rather than general problems.  Since I find SHOULD very 
useful, to me it makes more sense to try to outline cases where SHOULD is 
problematic, and provide advice for those cases, than to try to get rid of it 
or change what it means.

e.g. For the specific case of optional features that must be negotiated, I 
don't think that SHOULD is the problem.  Rather I think that optional features 
are too common.  That's not to say that optional features and feature 
negotiation are never useful, particularly when extending a protocol that is 
already well-established in the field.  But if making features optional is seen 
by WGs as a way to avoid making hard decisions about what is required to 
interoperate, that really is a problem.  It just doesn't have anything to do 
with SHOULD.

Keith

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