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

[Tomasz Zieleniewski]

2009/5/13 Yevgen Krapiva <ykrapiva at gmail.com>

> 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 ?

No this timer is required for the purpose of ACK retransmissions.

> 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 ?

Stateful proxy core may start processing of the corresponding server client
transactions as
soon as all client transactions move to completed state.

Best regards,
Tomasz

>
>
>
>
> 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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