Re: [sipcore] draft-sparks-sipcore-refer-explicit-subscription-02: comments

[Robert Sparks <[e-mail]>]

On 11/10/14 9:07 AM, Brett Tate wrote:
> Hi,
>
> The following are some comments concerning
> draft-sparks-sipcore-refer-explicit-subscription-02.
>
> Thanks,
> Brett
>
> -------
>
> If something within this draft allows a RFC 6665 compliant notifier to not
> supply a GRUU Contact within call's dialog, please clearly indicate it.
> For instance if true, indicate that the notifier is not required to supply
> a GRUU Contact if notifier supports 'nosub' (even if referrer does not
> support 'nosub').
>
> Section 6 indicates the following:
>
> "The 'explicitsub' and 'nosub' option tags MAY appear in the Supported
>   header field of SIP messages, and in sip.extensions feature tag
>   defined in [RFC3840].  This signals only that the UA including the
>   value is aware of the extensions.  In particular, a UA can only
>   invoke the use of one of the extensions in a request.  A User-Agent
>   Server (UAS) that is processing a REFER request that lists
>   'explicitsub' or 'nosub' in its Supported header field and wishes to
>   use one of those extensions will return a 421 response indicating
>   which extension is required.
>
>   OPEN ISSUE: This description of the use of 421 is not yet perfectly
>   aligned with RFC3261's definition."
>
> I think that the open issue should be closed by not mandating the 421
> response (at least if REFER was sent within dialog).  Similar to the RFC
> 3262 behavior, the UAS can indicate it is being used by including
> option-tag within Require header of 2xx response.
Hi Brett -

I sent text last week proposing how to address this (Subject 'Open issue 
in refer-explicit-subscriptions').
Was that text problematic for you?

RjS