Subject: [SIP] Re-invites in a multi-party call

From: Deepika Giri <[email-masked]>
Date: Mon, 11 Jun 2001 15:33:29 +0530

Hi,

I am trying to implement a multi-party conference control application in SIP
using 3pcc.
My problem is this:

Usr A is currently in a conference call with User B and C, now it wishes to
put the current conference call on hold, by sending a re-INVITE, but what
will be the sip request url for this re-invite, does it send hold messages
to B and C individually?  If it has to do this, it has to maintain the users
currently in the conference call, but does a standard SIP-phone maintain
this information?   The number of users in a conference is not always known
to each client in a conference, there has to be a mechanism by which the
users get a fresh list of participants every time one leaves the call or
joins in. Can someone explains how such a feature would be implemented in a
SIP phone?

I need to know how a sip phone behaves in this scenario, b'cos my 3rd party
application has to handle this "hold " invocation by any of the users in a
call.

Can you please clarify?

Thanks
Deepika

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---

From: "Ranjit Avasarala" <[email-masked]>
Date: Mon, 11 Jun 2001 14:00:01 -0500

Hi  Deepika,

      to put usr B on HOLD usr A sends a Re INVITE (HOLD) message with a
session description containing a null (0.0.0.0) address.
when used with SDP the 'c' address field of media types is set to 0.

Regards
Ranjit
Mascon Communication Technologies
http://www.masconit.com

----- Original Message -----
From: Deepika Giri <[email-masked]>
To: <[email-masked]>
Cc: <[email-masked]>
Sent: Monday, June 11, 2001 5:03 AM
Subject: [SIP] Re-invites in a multi-party call

Hi,

Can you please clarify?

Thanks
Deepika