答复: Re: 答复: Re: PRACK: Change MUST requirement to include SDP offer in first reliable provisional response

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Hi,

Why you answer the mail you have answered? :)

And the newer mails(on 2009-04-09) you have not answered yet.

Thanks.

Gao




Christer Holmberg <christer.holmberg@xxxxxxxxxxxx>
发件人:  <sipping-bounces@xxxxxxxx>

2009-04-07 15:43

收件人
<gao.yang2@xxxxxxxxxx>, Paul Kyzivat <pkyzivat@xxxxxxxxx>
抄送
<sipping-bounces@xxxxxxxx>, <sipping@xxxxxxxx>
主题
Re: [Sipping]        答复: Re:  PRACK: Change MUST requirement to include SDP offer in        first reliable provisional response





Hi,
 
I think we already a while ago agreed on the principle that it shall be possible to send a non-200 response to a PRACK (not only for offer/answer, but possibly also due to other reasons).
 
And, in that case, why would an intermeidate be allowed to reject a PRACK, but not the UAS?
 
Regards,
 
Christer
 
 


From: sipping-bounces@xxxxxxxx [mailto:sipping-bounces@xxxxxxxx] On Behalf Of gao.yang2@xxxxxxxxxx
Sent:
Tuesday, April 07, 2009 4:33 AM
To:
Paul Kyzivat
Cc:
sipping-bounces@xxxxxxxx; sipping@xxxxxxxx; Christer Holmberg
Subject:
[Sipping] 答复: Re: PRACK: Change MUST requirement to include SDP offer in first reliable provisional response



More points of view to this question:


By RFC3262:
1. "Retransmissions of the reliable provisional response cease when a matching PRACK is received by the UA core."


2. "If the PRACK does match an unacknowledged reliable provisional response, it MUST be responded to

  with a 2xx response."


So, when UAs receive a matching PRACK, it will stop re-transmit the reliable provisional response(18x). And the response

to PRACK MUST be 2xx.


It is simple and clear. And when UAs receive non-2xx response to PRACK, it is clear that the other side do not receive the

PRACK. It can send a new PRACK(CSeq++, the same RAck).


And now, we can use PRACK to send "precondition notification" and "codec refine". When we need to issue session modification like adding codec,
adding/removing media streams, we MUST using Re-INVITE/UPDATE.


I think we should not re-write RFC3262 to allow the UA to reject the PRACK.





Paul Kyzivat <pkyzivat@xxxxxxxxx>
发件人:  sipping-bounces@xxxxxxxx

2009-04-06 20:16


收件人
"Rockson Li (zhengyli)" <zhengyli@xxxxxxxxx>
抄送
sipping@xxxxxxxx, Christer Holmberg <christer.holmberg@xxxxxxxxxxxx>
主题
Re: [Sipping] PRACK: Change MUST requirement to include SDP offer in        first reliable provisional response







I think I also agree. There are a lot of things that in hindsight we
probably would have done differently. But that is water over the dam. We
are where we are.

               Paul

Rockson Li (zhengyli) wrote:
> I totally agree with Hadriel's insight here.
>
> It should have been avoided to put too many jobs into PRACK,
>
> I miss KISS(Keep It Simple and Stupid) principle
>
>  
>
> Regards,
>
> -Rockson
>
> ------------------------------------------------------------------------
> *From:* sipping-bounces@xxxxxxxx [mailto:sipping-bounces@xxxxxxxx] *On
> Behalf Of *Hadriel Kaplan
> *Sent:* Tuesday, March 31, 2009 9:50 PM
> *To:* Christer Holmberg; sipping@xxxxxxxx
> *Subject:* Re: [Sipping] PRACK: Change MUST requirement to include SDP
> offer in first reliable provisional response
>
>  
>
>  
>
> In hindsight I’m thinking we probably also shouldn’t have made the SDP
> answer (or another offer) required or even possible in the PRACK
> either.  I think it should have been for one and only one purpose: to
> acknowledge receipt of the provisional response.
>
>  
>
> -hadriel
>
>  
>
>  
>
>
> ------------------------------------------------------------------------
>
> _______________________________________________
> Sipping mailing list  https://www.ietf.org/mailman/listinfo/sipping
> This list is for NEW development of the application of SIP
> Use sip-implementors@xxxxxxxxxxxxxxx for questions on current sip
> Use sip@xxxxxxxx for new developments of core SIP
_______________________________________________
Sipping mailing list  https://www.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP
Use sip-implementors@xxxxxxxxxxxxxxx for questions on current sip
Use sip@xxxxxxxx for new developments of core SIP



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Sipping mailing list  https://www.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP
Use sip-implementors@xxxxxxxxxxxxxxx for questions on current sip
Use sip@xxxxxxxx for new developments of core SIP

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