Well the problems that I see: - How do you specify a group? If all phones in the local area network start talking that is probably not the right way to do it - How do you send ACK? Also by multicast? - How do you send BYE? - How do you deal with packet loss? - What about Record-Route problems?
Thats what just comes to my mind. I think it is much easier to keep the signalling non-multicast and set the session up after the phone starts. CS > -----Original Message----- > From: Mudigonda, Saisrikiran [mailto:[EMAIL PROTECTED] > Sent: Wednesday, June 07, 2006 6:46 AM > To: Christian Stredicke; [email protected] > Cc: CTO YAN Renxiang > Subject: RE: [Sip-implementors] How to create a multicast > session using SIP? > > Aren't most multicast sessions public? May be you're right > when the case relates to setting up a private group address. > Can you please specify some problems that may be caused for > my benefit? > Thanks, > Sai. > > -----Original Message----- > From: Christian Stredicke [mailto:[EMAIL PROTECTED] > Sent: Wednesday, June 07, 2006 3:24 PM > To: Mudigonda, Saisrikiran; [email protected] > Cc: CTO YAN Renxiang > Subject: RE: [Sip-implementors] How to create a multicast > session using SIP? > > You mean the signalling should be multicast as well? That > will cause a lot of problems. I think it should be possible > to set the group up using TLS, so that no one in the middle > would see the parameters of the paging group (e.g. SRTP key). > > CS > > > -----Original Message----- > > From: Mudigonda, Saisrikiran [mailto:[EMAIL PROTECTED] > > Sent: Wednesday, June 07, 2006 3:46 AM > > To: Mudigonda, Saisrikiran; Christian Stredicke; > > [email protected] > > Cc: CTO YAN Renxiang > > Subject: RE: [Sip-implementors] How to create a multicast session > > using SIP? > > > > Sorry typo. > > > > B can then send an INVITE (not SUBSCRIBE) > > > > > > -----Original Message----- > > From: Mudigonda, Saisrikiran > > Sent: Wednesday, June 07, 2006 12:43 PM > > To: 'Christian Stredicke'; [email protected] > > Cc: CTO YAN Renxiang > > Subject: RE: [Sip-implementors] How to create a multicast session > > using SIP? > > > > We could use an initial INVITE for A to join a multicast > session with > > maddr parameter in the Request-URI. > > > > When A wants B to join the same multicast conference as he is > > subscribed to, he can send an INFO message with the > required multicast > > session information. B can then send a SUBSCRIBE message to the > > multicast address specified in the INFO message. > > > > Or > > > > A could send an INVITE to B with a JOIN header containing the > > multicast address. > > > > Thanks, > > Sai. > > > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] On Behalf Of > > Christian Stredicke > > Sent: Wednesday, June 07, 2006 6:44 AM > > To: [email protected] > > Cc: CTO YAN Renxiang > > Subject: Re: [Sip-implementors] How to create a multicast session > > using SIP? > > > > I think we need to seriously take a look at this. > > > > IMHO, the source needs to set up a dialog a long time before the > > actual paging can start. Otherwise, there will be a burst of INVITE > > which will make this difficult in offices with lets say > 1000 phones. > > Then the phone must listen to the multicast group all the time and > > play the annoucement whenever there is a paging going on. > > > > I think the SDP would look like this: > > > > v=0 > > o=carol 28908764872 28908764872 IN IP4 224.3.4.5 > > s=- > > c=IN IP4 224.3.4.5 > > t=0 0 > > a=multicast-recvonly > > m=audio 3000 RTP/AVP 0 > > a=rtpmap:0 PCMU/8000 > > m=audio 3002 RTP/AVP 3 > > a=rtpmap:3 GSM/8000 > > > > I think we need an attribute like the "multicast" (just a > wild guess) > > that indicates that the UA should just listen to that group and not > > send any media to the group. > > > > In the example above, the phone could tune into PCMU or GSM > codecs on > > different ports. > > > > Any other ideas? > > > > > > Christian > > > > > -----Original Message----- > > > From: [EMAIL PROTECTED] > > > [mailto:[EMAIL PROTECTED] On Behalf > > Of CTO YAN > > > Renxiang > > > Sent: Tuesday, June 06, 2006 4:01 AM > > > To: [email protected] > > > Subject: [Sip-implementors] How to create a multicast > session using > > > SIP? > > > > > > Hi, all, > > > > > > How to create a multicast session using SIP? Is the following > > > description correct? 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. > > > -but when will A join the session? > > > > > > Case (2) A joins a multicast session independently. > > > A sends INVITE to whom? when send IGMP join message? > > > > > > Other cases? > > > > > > Regards, > > > Renxiang <mailto:[email protected]> > > > _______________________________________________ > > > Sip-implementors mailing list > > > [email protected] > > > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > > > > > > > > > > > > > _______________________________________________ > > Sip-implementors mailing list > > [email protected] > > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > > > > > > > > > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
