Subject: [Sip] how to create a multicast session using SIP?

From: "CTO YAN Renxiang" <[email-masked]>
Date: Mon, 5 Jun 2006 19:46:41 +0800

Hi, all,

How to create a multicast session using SIP? Is the following description right?
Two kinds of case:
Case (1) A invites B to join a multicast session.
  A sends a INVITE to B, the multicast address is included in SDP part of INVITE message. 
  B will then join the session by sending an IGMP to join the multicast session.
  ...

Case (2) A joins a multicast session independently.
 A sends INVITE to whom? when send IGMP join message?

Other cases?

Regards,
Renxiang

_______________________________________________
Sip mailing list  https://www1.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use [email-masked] for questions on current sip
Use [email-masked] for new developments on the application of sip

---

From: "Tarun Kapoor" <[email-masked]>
Date: Mon, 5 Jun 2006 09:57:24 -0400

Hi Renxiang,

	I believe this question is more suited for the "SIP Implementors"
mailing list ([email-masked]).  But to answer your
question, you always need to embedded any media session parameters (such as
multicast session) in the SDP of any INVITE.  However, in the first case,
you are directly inviting B to the multicast media session (who will then
join the multicast session via IGMP, assuming it accepts the INVITE with a
200 response), and in the second case, A needs to determine whom to invite
to the session (which is independent of SIP) and sends the INVITE to the
those users, and if they accept with a 200 response, then they will also
join the multicast session via IGMP.

	Alternatively, in the second case, you could send the INVITE itself
to a multicast address (i.e., send the SIP message to a multicast address,
rather than a unicast address).  Anyone listening for SIP messages on that
multicast address will automatically receive the INVITE and can determine
whether to join independently of any specific (i.e., unicast) INVITE
received.  However, in practice, I don't know how many implementations use
the SIP over multicast scenario.

Regards,
 
Tarun Kapoor
Pangean Technologies, LLC
W: +1 (877) 472-6432
F: +1 (877) 581-7616
M: +1 (917) 698-3450
www.pangeantech.com
"...communications without boundaries"

-----Original Message-----
From: CTO YAN Renxiang [mailto:[email-masked]] 
Sent: Monday, June 05, 2006 7:47 AM
To: [email-masked]
Subject: [Sip] how to create a multicast session using SIP?

Hi, all,

How to create a multicast session using SIP? Is the following description
right?
Two kinds of case:
Case (1) A invites B to join a multicast session.
  A sends a INVITE to B, the multicast address is included in SDP part of
INVITE message. 
  B will then join the session by sending an IGMP to join the multicast
session.
  ...

Other cases?

Regards,
Renxiang

_______________________________________________
Sip mailing list  https://www1.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol Use
[email-masked] for questions on current sip Use
[email-masked] for new developments on the application of sip