Paul Kyzivat wrote:
> I think the part that is not clearly specified is when the referee may
> terminate the subscription. It must send at least one NOTIFY, but I
> think it principle it could set the subscription state to terminated in
> the very first NOTIFY if it wanted, even though the referred request is
> still incomplete.
From 3515:
Note that agents accepting REFER and not wishing to hold
subscription state can terminate the subscription with this initial
NOTIFY.
>
> Conversely, AFAIK there is no requirement that the subscription be
> terminated when the referred operation completes. If the REFER was for
> an INVITE, normally the subscription is terminated on the final
> response, but it could in principle keep sending notifications while the
> call is active.
That's what I thought but actually the RFC does state that the resource
subscribed to is the triggered transaction and as such it must terminate
when the transaction terminates. 3515 again:
The final NOTIFY sent in response to a REFER MUST indicate
the subscription has been "terminated" with a reason of "noresource".
(The resource being subscribed to is the state of the referenced
request).
and later:
The lifetime of the state being subscribed to is
determined by the progress of the referenced request.
I thought there was even more explicit text but can't find it right now.
Thanks,
Anders
>
> For the original question, take a look at RFC 4488, defining the
> norefersub option. If the referror doesn't want the subscription then
> this is an option. But it isn't an option for the referee on its own.
>
> Paul
>
> Scott Lawrence wrote:
>> On Thu, 2008-02-21 at 16:33 -0800, Dushyant Godse wrote:
>>> Hello
>>> I was referencing the RFC 3515 regarding messaging for transfers based
>>> on SIP REFER.
>>> Is the UA processing the REFER required to send NOTIFY subscription
>>> event messages to the sender agent notifying the progress of the
>>> transfer like 100 trying, 180 ringing, 200 OK. Is this a MUST?
>>>
>>> I am pasting below a snippet of the RFC which says it must. I would like
>>> to confirm this within the forum
>>> If a REFER request is accepted (that is, a 2xx class response is
>>> returned), the recipient MUST create a subscription and send
>>> notifications of the status of the refer as described in Section
>>> 2.4.4.
>> What is the ambiguity? MUST means what it says.
>>
>>
>> _______________________________________________
>> Sip-implementors mailing list
>> [email protected]
>> https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
>>
> _______________________________________________
> Sip-implementors mailing list
> [email protected]
> https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
>
_______________________________________________
Sip-implementors mailing list
[email protected]
https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
