Comments inline:

> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]]On Behalf Of Murali
> Medikonda
> Sent: Wednesday, May 22, 2002 12:01 PM
> To: [EMAIL PROTECTED]
> Cc: Don McKinney
> Subject: [Sip-implementors] OFFER/ANSWER after Hold
>
>
> All,
>
>     consider the following scenario:
>
>     Client A and Client B are in a stable call (SDP is offered in the
> INVITE and
>                                                                    is
> ANSWERed in the 200OK)
>
>
>      Client A holds Client B by sending a re-INVITE (IP address set to
> 0.0.0.0)
>                            (I realize this method of holding a session
> is no longer recommended)
>
>      Now, when Client A reverts back to B, what should client B's
> behaviour be when
>
>      (a) Client A sends a re-INVITE with SDP - offer SDP (new or same as
> earlier) and expect an
>                      answer in the 200OK)
>

If A offers the same SDP, B will answer with the very same SDP. If some of
the existing session characteristics have been modified and/or new media has
been added, B will respond accordingly. If new media is to be added, it has
to be added to the already negotiated SDP, though.

>      (b) Client A sends an re-INVITE - with NO SDP - i.e wait for the
> offer in 200OK and send an
>                      answer in the ACK.
>

See the post to the previous question on the list. The UAS would respond
with Global Error (6xx).

Regards,

--victor

Victor Paulsamy               E-mail: [EMAIL PROTECTED]
Senior Software Engineer      Phone : 650.930.1339 (Direct)
Zapex Technologies, Inc.      Phone : 650.930.1300 (Main)
Mountain View, CA 94043       Fax   : 650.930.1399

>     I realize, in general, this is how OFFER/ANSWER model works!! Not
> counting the Outstanding
> Offers case, are there any restrictions or limitations to this model.
>
> Specifically, can I do either (a) or (b), when applied to situation
> described above viz., when a
> session is held and is being retrieved.
>
> Appreciate your commments
>
> Murali
>
>
>

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