Subject: Re: qb - a new floor ctrl tool fro asking questions

From: Ross Finlayson <[email-masked]>
Date: Wed, 23 Apr 1997 16:19:36 -0700 (PDT)

At 07:13 AM 4/23/97 -0700, Radhika Malpani wrote:
>Qb does send the grant-floor directive to vic & vat using the conference bus
>mechanism.

This reminds me:

Where is the 'conference bus' documented/described?  It's some sort of
multicast-based intra-node (TTL 0?) command protocol, right?  Even if it's
always used internally within a client machine (so, is not a true 'network'
protocol), it would still be a good thing to define properly and standardize
(informally, at the very least), so that lots of different a/v tools could
use it.

        Ross.

---

From: Henning Schulzrinne <[email-masked]>
Date: Thu, 24 Apr 1997 08:03:57 -0400

> (informally, at the very least), so that lots of different a/v tools could

Note that this is not the only local conference bus. See my NOSSDAV'95
paper, which provides documentation on a text-based version.

@INPROCEEDINGS{Schu9504:Dynamic,
AUTHOR="Schulzrinne, Henning",
TITLE="Dynamic Configuration of Conferencing Applications using
Pattern-Matching Multicast",
BOOKTITLE=nossdav,
PUBLISHER="Springer",
SERIES="Lecture Notes in Computer Science (LNCS)",
ADDRESS="Durham, New Hampshire",
YEAR=1995,
MONTH=apr,
PAGES="231-242",
ABSTRACT="Multimedia conferencing systems are usually large, complex
software systems.  We describe a local control architecture and
communication protocols that allow to tie together media agents,
controllers and auxiliary applications such as media recorders and
management proxies into a single conference application.  Unlike other
systems, control of a single conference can be shared between several
controllers.  Each media can be handled by one or more independent
media agents.  Parts of the system have been implemented using an
IP-multicast-based audio conferencing tool (NeVoT).  The
communicating applications disseminate state and control information
through a replicator.  The replicator mainly limits distribution of
messages based on expressed interest of other applications, thus
implementing an application-level, receiver-driven local multicast.
It also automatically starts applications as needed.  The same
functionality was also implemented IP multicast restricted to the
local host.",
KEYWORDS="multimedia; conferencing; conference control; multicast",
URL="ftp://gaia.cs.umass.edu/pub/Schu9504:Dynamic.ps.gz",
ENTRYBY=Sc
}

For one approach of integrating this with SIP, RTSP, et al., see

@INPROCEEDINGS{Schu9705:Comprehensive,
AUTHOR="Henning Schulzrinne",
INSTITUTION="Columbia University",
SPEAKER="Henning Schulzrinne",
TITLE="A comprehensive multimedia control architecture for the
{Internet}",
BOOKTITLE=nossdav,  
ADDRESS="St. Louis, Missouri",
YEAR=1997,   
MONTH=may,   
DAY="19-21",
REFERENCES=46,
KEYWORDS="SIP; RTSP; signaling; Internet telephony; continuous media;
video on demand; audio on demand",
URL="http://www.cs.columbia.edu/~hgs/papers/Schu9705:Comprehensive.ps.gz",
ENTRYBY=Sc
}

-- 
Henning Schulzrinne         email: [email-masked]
Dept. of Computer Science   phone: +1 212 939-7042
Columbia University         fax:   +1 212 666-0140
New York, NY 10027          URL:   http://www.cs.columbia.edu/~hgs