Jonathan
When I said UAS receives provisional responses, I meant to say the UAS stack
is asked by the UAS application to send provisional responses. The confusion
was unfortunate.
The question is this -
What is an UAS SIP stack to do if it receives requests from the UAS
application to send multiple provisional responses reliably and the call is
answered before the first PRACK is received and the 200 is to be sent by
the UAS application.
What should be done with the unsent provisional responses that are queued
pending the receipt of the first PRACK.
Venkat
> -----Original Message-----
> From: Arunachalam Venkatraman [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, May 16, 2001 9:17 PM
> To: SIP Implementors
> Cc: Jonathan Rosenberg
> Subject: [Sip-implementors] Unsent Reliable Provisional
> Responses after
> final response
>
>
> I have re-formulated an earlier question with a better
> explanation (I hope!)
>
> In Section 6.3 of the 100-rel draft's 03 version, it is said -
>
> The UAS MUST NOT send a second reliable provisional
> response until the first is acknowledged. After the first, it is
> RECOMMENDED that the UAS not send an additional reliable
> provisional
> response until the previous is acknowledged.
>
>
> It is also said in the same section -
>
> A UAS MUST NOT send new
> reliable provisional responses (as opposed to retransmissions of
> outstanding ones) after sending a final response to a request.
>
>
> Suppose a UAS receives the following in rapid succession (or
> any other valid
> sequence of provisionals followed by 200)
Why would a UAS receive provisionals? A UAS sends them.
>
> 182 2 in Queue
> 182 1 in Queue
> 183 Session Progress
> 180 Ringing
> 2XX/3XX/ 4XX/5XX/6XX
>
> The final response may be available to be sent even before
> the PRACK to the
> first one is received.
> In that case, (based on the above extracts from the draft) the other
> provisional responses MUST not be sent.
>
> However, there may be useful information in the attachments
> (eg. ISUP INFO
> for SIP-T, with cause code) that should be
> conveyed reliably but cannot be sent.
If the UAS wants to send those provisionals reliably before sending the
final response, it can do so.
>
> If the final response is 200 OK, the attachment in that
> response is adequate
> and there should be no loss of information by dropping the provisional
> responses. But if the final response is a failure response,
> the attachment
> in an earlier 183 will have IEs that are required, for example, to
> correctly interpret the cause of the call failure.
>
> Should we queue up a non-200 final response to wait for the
> first PRACK?
That is an implementation decision.
-Jonathan R.
---
Jonathan D. Rosenberg, Ph.D. 72 Eagle Rock Ave.
Chief Scientist First Floor
dynamicsoft East Hanover, NJ 07936
[EMAIL PROTECTED] FAX: (973) 952-5050
http://www.jdrosen.net PHONE: (973) 952-5000
http://www.dynamicsoft.com
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