[SIPForum-discussion] Choosing the best response. Clarification needed

[Yevgen Krapiva]

Hi. I'm using Ekiga, Xlite softphones, but we are not talking about
it, it's about correct statefull proxy behavior.

2009/5/13, trungdo <trungdo at patton.com>:
>
>
> HI,
>
> You can change the invite time out waiting less then 32 seconds. This case
> is use when have 2 UAS, the UAC send first register invite to active server
> before time out. After that the UAC send to second Server.
>
> What is the UAC are u using ? That's VIP gateway or softphone. ?
>
>
> Regards
>
> trungDo
>
> On 5/13/09 7:22 PM, "Yevgen Krapiva" <ykrapiva at gmail.com> wrote:
>
>> Yes.
>>
>>> then proxy sends final response when all transaction end.
>>
>> It will happen when Timer D fires.
>>
>>> so an absolute minimum of 32s is used instead of basing Timer D on T1.
>>
>> Am I (UAC) supposed to wait 32 seconds before I get an answer from
>> proxy that my request failed ? It's too long. O_o
>> I'm saying that proxy must not wait when client transaction finally go
>> to terminated state. I think that COMPLETED state already gives me a
>> right to send the final response to UAC. Why not ?
>>
>>
>>
>> 2009/5/13, Tomasz Zieleniewski <tzieleniewski at gmail.com>:
>>> Hi,
>>>
>>> I think You have mistaken the completed with terminated state.
>>> When proxy receives 300-699 response this causes a proxy client
>>> transaction
>>> to
>>> transition to completed state. In which for unreliable transport it
>>> starts
>>> D
>>> timer
>>> in order to generate ACK for transaction response retransmissions.
>>> When D timer fires transaction transitions to completed state. (proxy
>>> removes any associated resources)
>>> Keep in mind that this a per transaction behavior. When there is forking
>>> at
>>> the proxy
>>> if the response is not 6xx or 200 then proxy sends final response when
>>> all
>>> transaction end.
>>>
>>> Kind regards,
>>> - Tomasz Zieleniewski
>>>
>>> 2009/5/12 Yevgen Krapiva <ykrapiva at gmail.com>
>>>
>>>> Hi.
>>>>
>>>> Here is a quote from RFC 3261 Response processing section in statefull
>>>> proxies:
>>>>
>>>>> 6.  Choosing the best response
>>>>>
>>>>>         A stateful proxy MUST send a final response to a response
>>>>>         context's server transaction if no final responses have been
>>>>>         immediately forwarded by the above rules and all client
>>>>>         transactions in this response context have been terminated.
>>>>
>>>> Should I treat the words "terminated transaction" as transaction in
>>>> TERMINATED state ? If yes, then keeping in mind that client
>>>> transactions created by proxy "live" for about 30 seconds in case of
>>>> 3XX-699 responses, then the UAC have to wait half a minute until the
>>>> proxy answers him.
>>>>
>>>> In other words: If client transaction created by proxy receives
>>>> 3XX-699 response, then it will elapse 30 seconds before transaction
>>>> goes from COMPLETED to TERMINATED state. All this time proxy have to
>>>> wait until it sends the final response to UAC.
>>>>
>>>> Is it normal ? Or should proxy choose the best response when all
>>>> client transactions goes to COMPLETED OR TERMINATED state ?
>>>> _______________________________________________
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>>>
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>
>