Title: RE: [Sip] Open Issue #58: Rejected mid-call SDP in 2xx

Hi Victor / everyone,

>Just to confirm, the scenario we are talking about is
>
> (part 1) User A <-----> User B    established with 2 streams (say)    
> (part 2)User A  -----> User B    re-INVITE Hold both streams
> User A <------ User B    200 OK with Hold SDP (2 way hold)
> User A  -----> User B    ACK and session is on hold now.
>
> NOW...
> (part 3) User A  -----> User B    a re-INVITE w/o SDP


>>In addition to the above two, the UAS can also send a third new SDP with
>>addition/deletion/modification of new/old/old streams if it intends, as all
>>characteristics of a session can be modified.

Yes, if you mean the scenario

(part 4)  User A ----> User B  a re-INVITE with modified SDP as you describe

then I think this is valid.  Whether or not user B accepts this SDP is of course a different matter.

Does anyone else agree with this?


Best Regards

Chris

Chris Hogg
Nortel Networks (UK).


-----Original Message-----
From: Victor Paulsamy [mailto:[EMAIL PROTECTED]]
Sent: 04 October 2001 19:49
To: Hogg, Chris [MDN05:EP30:EXCH]; stoshniwal
Cc: SIP; sip; brett; 'Christer Holmberg'; Victor Paulsamy
Subject: RE: [Sip] Open Issue #58: Rejected mid-call SDP in 2xx


> Just to confirm, the scenario we are talking about is
>
> User A <-----> User B    established with 2 streams (say)
> User A  -----> User B    re-INVITE Hold both streams
> User A <------ User B    200 OK with Hold SDP (2 way hold)
> User A  -----> User B    ACK and session is on hold now.
>
> NOW...
> User A  -----> User B    a re-INVITE w/o SDP
>
> Is this correct?
>
>
> If so, I have a feeling I agree with Brett. A response to a
> re-INVITE w/o SDP need not have a held SDP even if the UAS
> was earlier put on hold.
>
> REASON: On the list it had earlier been agreed that change
> of IP and/or port in ANY offer after the original INVITE
> is allowed. In case of responding to a re-INVITE w/o SDP,
> the offer is in the 200 OK to this re-INVITE. The UA SHOULD
> be allowed to send either of:
>
> 1. A hold SDP (like the previous 200 OK response that it sent)
>    if it still wants A to be on hold.
> 2. A unhold SDP as this involves only a change of IP (or
>    media stream) as it may now want User A to come off hold.
>
> What the UAS MUST NOT do is add a third stream (in addition
> to the 2 already accepted originally). It is free to put one
> or more of the 2 "originally in use streams" on/off hold.
>
> Comments please?
>

In addition to the above two, the UAS can also send a third new SDP with
addition/deletion/modification of new/old/old streams if it intends, as all
characteristics of a session can be modified.

Comments?

Warm regards,

--victor

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