On 1/29/19 11:29 AM, Alex Balashov wrote:
Hello,
On Tue, Jan 29, 2019 at 11:21:01AM -0500, Paul Kyzivat wrote:
5.13 says: "Attributes MUST be registered with IANA", so why do you
say this isn't illegal?
Upon reflection, you are certainly correct. I suppose the notion of
legality I had in mind was implicitly to do with grammatical validity /
request intelligibility rather than policy.
So, if the attribute is not registered and if the foregoing applies to
unsupported but registered attributes, and is therefore illegal, then,
in the context of one of those acrimonious "how dare you say I'm not
following the standards?" disputes, does this--in any _reasonable_ way,
taking purely political phenomena out of it--open the door to the
receiver/answerer vendor arguing that an endpoint making use of an
unregistered attribute (that is to say, illegally so) is not justified
in expecting predictable or standards-prescribed results in the answer?
In this case I think the UAC *should* expect that a conforming recipient
will act in a conforming way and *ignore* the attribute - and thus *not*
include it in the answer. This is because a conforming recipient cannot
distinguish the non-conforming use by the UAC from use of a standard
extension not known to the recipient.
So the UAC *can* game the system and use this to negotiate with another
UA implementing the same unregistered non-conforming extension.
But you can still call them out for being non-conforming.
Thanks,
Paul
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