Subject: Re: [Sip] Regarding Conference Call Setup

From: seshu <[email-masked]>
Date: Thu, 20 Sep 2001 10:06:52 -0700 (PDT)

My Comments are inline..

--- LOCAL <[email-masked]> wrote:
> Hi,
> the document
'http://search.ietf.org/internet-drafts/draft-rosenberg-sip-conferencing-mo
> d
> els-01.txt' says that
> the multicast address can be obtained from media
> line (c=) parameter of
> SDP,
> in which case could you please
> explain the maddr field in any of sip headers?
> Actually Iam confused after
> seeing the
> example given in 16.2.1 in RFC 2543, how do I relate
> the following
> multicast
> addresses:

 The multicast address in the maddr parameter of the
headers indicates the address for SIP messages. The
multicast address in the c= line indicates the address
where the endpoint wants to listen to the media
streams. They are totally for different purpose.

> maddr=239.128.16.254;ttl=16
> and
> c=IN IP4 224.2.0.1/127 (what is this '/127' )

 Here, 127 is the ttl. 
You need to refer to the SDP RFC 2327 for more
details. 

Rgds
Seshu

  

> > > -----Original Message-----
> > > From: Madhav B [mailto:[email-masked]]
> > > Sent: Wednesday, September 19, 2001 5:53 AM
> > > To: [email-masked]
> > > Subject: [Sip] Regarding Conference Call Setup
> > >
> > >
> > >
> > >
> > > Hello,
> > >
> > >         I have some doubts regarding the
> conferece call setup
> > >
> > >         1. wheather the non-initiator can invite
> the third or a
> > > subsequent
> > > person, which means if A initiates a conference
> call to B and C,
> > > is it possible for B or C to inivite D?
> > >
> > >   yes. but if B or C have to invite D , then
> they have to put
> > > the current
> > > call leg on hold and then send
> > >   INVITE to D.
> >
> > No, of course that is not true.
> >
> > The means for adding users to a conference depend
> on the conference
> model.
> > Its all spelled out quite explicitly in:
> >
> >
>
http://search.ietf.org/internet-drafts/draft-rosenberg-sip-conferencing-mod
> e
> > ls-01.txt
> >
> >
> > >
> > >         2. is SIP signalling unicast or
> multicast? i,e I want to know
> > > wheather INVITE or subsequent methods are sent
> sent point to point.
> > > supposing A, B, C and D are in conference, if D
> wants quit does
> > > it send send BYE just to the initiator or to all
> of the remaining
> > > participants?
> >
> > See the above document.
> >
> > -Jonathan R.
> >
> > ---
> > Jonathan D. Rosenberg, Ph.D.                72
> Eagle Rock Ave.
> > Chief Scientist                             First
> Floor
> > dynamicsoft                                 East
> Hanover, NJ 07936
> > [email-masked]                     FAX:  
> (973) 952-5050
> > http://www.jdrosen.net                      PHONE:
> (973) 952-5000
> > http://www.dynamicsoft.com
> >
> 
> 
> _______________________________________________
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> This list is for NEW development of the core SIP
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> Use [email-masked] for questions
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> 
> 

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