-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 08/30/2011 08:44 AM, Keith Moore wrote: > > On Aug 30, 2011, at 11:38 AM, Marc Petit-Huguenin wrote: > >> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 >> >> On 08/30/2011 07:58 AM, Keith Moore wrote: >>> On Aug 30, 2011, at 10:54 AM, Marc Petit-Huguenin wrote: >>> >>>> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 >>>> >>>> On 08/30/2011 07:35 AM, Keith Moore wrote: >>>>> On Aug 30, 2011, at 10:14 AM, Marc Petit-Huguenin wrote: >>>>> >>>>>> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 >>>>>> >>>>>> 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.
The meaning of SHOULD is clear for the authors (it "mean[s] that there may exist valid reasons in particular circumstances to ignore a particular item, but the full implications must be understood and carefully weighed before choosing a different course."), the problem is that some implementers use a different meaning (I do not have to implement this if it is inconvenient or difficult for me to implement), vendors another one (SHOULD gave us the right to not implement it). I even read somewhere, perhaps on this list, about a vendor that rejected any bug report against a SHOULD. Conditional MUST, in my opinion, does not have this problem. > > 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. - -- Marc Petit-Huguenin Personal email: m...@petit-huguenin.org Professional email: petit...@acm.org Blog: http://blog.marc.petit-huguenin.org -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iEYEARECAAYFAk5dCosACgkQ9RoMZyVa61e8iwCfZccbWf20L0VaDtBFH6ekmhm5 l30AoJmTDscY/dAGwjfU3toAnydGZHft =pbTY -----END PGP SIGNATURE----- _______________________________________________ Ietf mailing list Ietf@ietf.org https://www.ietf.org/mailman/listinfo/ietf
