[Serusers] rfc 3262 support

[Klaus Darilion]

Greger V. Teigre wrote:
> I think the idea is that a proxy can send a provisional response to the 
> UAC and thus take responsibility for the transaction towards the (real) 
> UAS, just like sending a 100 Trying... before forwarding. The UAS has 
> not yet received the INVITE (or whatever message we are talking about) 
> and thus to tag is not yet set.

This is the standard transaction stateful call setup - there is no 
reliability of provisional responses.

regards
klaus

> g-)
> 
> Klaus Darilion wrote:
>> Hi Kamal!
>>
>> I reconsidered by previous answer and found that there is no Cseq 
>> Problem as CSeq may have gap.
>>
>> But reading your snippet: I've never seen any client yet sending 
>> provisional responses without to-tag. Thus, even if the proxy could 
>> generate reliable responses it wouldn't be used often.
>>
>> regards
>> klaus
>>
>> Kamal.Mann at t-systems.com wrote:
>>> Hi Darilion
>>> Please check the following snippet from rfc-3262
>>> "An element that can act as a proxy can also send reliable provisional
>>> responses.  In this case, it acts as a UAS for purposes of that
>>> transaction.  However, it MUST NOT attempt to do so for any request that
>>> contains a tag in the To field.  That is, a proxy cannot generate
>>> reliable provisional responses to requests sent within the context of a
>>> dialog.  Of course, unlike a UAS, when the proxy element receives a
>>> PRACK that does not match any outstanding reliable provisional response,
>>> the PRACK MUST be proxied."
>>>
>>> Regards
>>> Kamal Mann
>>>
>>> -----Original Message-----
>>> From: Klaus Darilion [mailto:klaus.mailinglists at pernau.at] Sent: 
>>> Thursday, October 19, 2006 3:03 PM
>>> To: Greger V. Teigre
>>> Cc: Mann, Kamal; serusers at lists.iptel.org
>>> Subject: Re: [Serusers] rfc 3262 support
>>>
>>> AFAIK PRACK is a client feature and is end to end. Thus, ser supports 
>>> PRACK as any other generic SIP request.
>>>
>>> Maybe you could fake PRACK requests or responses between a PRACK capable
>>>
>>> client and the proxy, but this will cause end-to-end CSeq mismatch 
>>> and would require a dialog stateful proxy to adapt the CSeqs.
>>>
>>> regards
>>> klaus
>>>
>>> Greger V. Teigre wrote:
>>>> AFAIK, this RFC is not implemented yet. As for a list, there is none 
>>>> right now, but it's on the to-do list :-)
>>>> g-)
>>>>
>>>> Kamal.Mann at t-systems.com wrote:
>>>>> Hi All
>>>>>
>>>>> Do SER supports 'rfc 3262 Reliability of Provisional Responses in 
>>>>> SIP'? Is there any list of standards supported by SER available??
>>>>>
>>>>>  
>>>>>
>>>>> Regards
>>>>>
>>>>> Kamal Mann
>>>>>
>>>>>  
>>>>>
>>>>>
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