Re: [RFC 4235 & draft-kuthan-sip-derive] 481 "Call doesn't exist" for initial SUBSCRIBE ?

On Thu, Nov 13, 2008 at 4:16 PM, Robert Sparks <[email protected]> wrote:
>
> On Nov 13, 2008, at 8:37 AM, Iñaki Baz Castillo wrote:
>
>> 2008/11/13 Paul Kyzivat <[email protected]>:
>>
>>> I understand the reasoning behind 481 but I am a *bit* troubled by it. It
>>> is
>>> a distinct semantic for 481, though one that is unambiguous. But 481
>>> already
>>> has three distinct meanings, so adding another doesn't seem like a great
>>> idea.
>>
>> I agree, imagine if you sends such a SUBSCRIBE but as refresh
>> SUBSCRIBE (in-dialog request), and you get 481. What does it mean?:
>>
>> a) The current SUBSCRIBE dialog doesn't exist anymore.
>> b) The indicated dialog in the "Event: dialog;call_id=xxx,to_tag=xxx"
>> doesn't exist.
>
> It might be a bit of a stretched analogy, but in this particular situation:
> The response to the subscribe definitely talks about the subscription usage
> (its the envelope)
> Information about the pointed-to dialog ending is carried in NOTIFYs (its
> the stuff in the envelope)

IMO, RFC 4235 establishes a relationship between the envelope and the content:
Section 3.4.  Subscription Duration
"In that case, when the dialogs terminate, so too does the subscription."
-- 
Victor Pascual Ávila
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