Subject: Minutes of Conf Ctrl BOF

From: [email-masked]
Date: Thu, 3 Dec 92 14:26:34 PST

Hi,

I've taken notes from the conference control BOFs and massaged them
into minutes.  I'm bound to have taken some literary license, so
it would be especially useful for you to comment, critique, and/or
correct these ramblings (editting tips welcome too).  I would like 
to post a finalized version to rem-conf early next week; please provide 
feedback before then.

I would also like to solicit recommendations for a reference list of 
reading materials to familiarize people with conference control issues.  
For instance, Oliver mentioned that there are some CCITT documents we 
should have a look at.  There are several other reports that I can think 
of which describe conference control in the context of prototype conferencing 
tools and systems.  I can put together a preliminary list.  Please forward 
any suggestions.

The next task is to come up with a charter.  I will attempt to draw up a
draft and post for comment.  As always, all input and involvement levels 
are encouraged.  

Eve

p.s. - As discussed at the BOF, we are going to establish a separate 
mailing list, [email-masked], sometime in the next day or so -- unless 
you think rem-conf will suit our needs.  Let me know what you think.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

During the RemConf BOF, there was a quorum of individuals interested 
in what has been referred to as "conference control" or "connection 
management".  Subsequently we held two impromptu (i.e., previously 
unscheduled) BOF sessions to discuss what, if anything, we as a group 
might be able to contribute to the remote conferencing architecture 
effort.  Below are minutes from those sessions.  Thanks goes to Dean 
Blackketter for acting as scribe.

Although we will continue to post information of general interest
to the rem-conf mailing list, we have set up a more narrowly focused
mailing list, [email-masked], for detailed discussions in the area 
of conference control.  To join the list, send a request to
[email-masked].

                   Conference Control BOF
                      November 16 & 17
                    IETF, Washington, D.C.

One task of the initial BOF sessions was actually to find a suitable
definition for "conference control", since the topic has been bandied
about for some time in the Remote Conferencing BOF and the Audio/Video
Transport WG.  By broadly defining multimedia conferencing as
collaborations in two dimensions (members and media), we defined
conference control as the management and coordination of (multiple)
conference members in (multiple) media.

How does conference control pertain to the ongoing RemConf efforts for
an overall remote conferencing architecture, and in particular to the
developments in the AVT WG of a real-time transport protocol?  We
agreed that there is a need for a session layer control protocol to
perform higher layer functions than the protocol proposed in the AVT
WG.  For example, three aspects of conference control might include 
session, connection and configuration management; session management 
entails who is involved in a conference, connection management involves 
the topology of who is seeing whom in each media, and configuration 
management is the negotiation of differences in end-system capabilities.

We identified the beginnings of some design criteria for this protocol.  
First, it should be kept simple, yet extensible.  We would like for it
to accommodate a range of session styles -- beyond the unmoderated
sessions already available through vat, dvc, nv et al.  We also
recognized the need to separate short-term from long-term functionality
goals.

We brainstormed about which functions MUST be supported versus which we
would like to have supported.  It falls out of our definition for conference 
control that, at minimum, support is needed for both membership and media 
control.  Membership control might include admission policies (such as 
user identification, user payment, meeting sponsorship), whereas media 
control might encompass capability descriptions, synchronization policies, 
and floor control (media focus).  In both dimensions, session setup, 
maintenance and/or modification must be supported.

Other features deemed important but probably of lower priority included 
security (in the form of authentication and encryption), as well as feedback 
channels for bandwidth balancing.  We also listed outside services to which 
we expect a conference control protocol to interface: a suite of directory
services for cataloguing users, conferences, and shared devices; bandwidth 
allocation and reservation mechanisms; and a scheme for multicast address 
allocation.  Our assumption is that eventually these outside services will 
be available.

To understand the range of capabilities to support in a conference
control protocol, we explored the types of sessions that might arise.
Our wishlist included a continuum of session scenarios (although the
picture below only lists a sample from the full range and only crudely
approximates an ordering).  "Secure" variations on these meetings were
also discussed.

        impromptu 
         hallway
         meetings        classroom        seminar      pay-per-view

    |-------|-------|--------|-------|-------|-------|-------|-------|

   pt2pt       arch design         panel          lecture           TV 
   phone        review/          discussion/                     broadcast
    call     "quilting bee"   presidential debate

Observations made about the spectrum were that there are different types 
of participation (active and passive), that there are gradations of 
identification policies (known vs anonymous participants), that there may 
be extreme variations in the degree of interconnectivity among participants, 
etc.  

We discussed that for simplicity (and implementation) sake, we are likely
to need to select a small number of session types that the protocol should
support.  A rough break down into four general session models was presented:

  1. Point-to-point calls
  2. Small, tightly-controlled sessions: N-way interconnectivity 
  3. Medium-sized, loosely-controlled sessions: lighter-weight model
  4. Very large, fixed sessions: unidirectional broadcasts

There was discussion that other standards bodies (CCITT) have explored
issues in some aspects of connection control (for B-ISDN).  In addition, 
existing prototype conferencing tools should be examined for leads on 
tradeoffs regarding conference management.  

Attendees:
	Dean Blackketter	[email-masked]
	Wo Chang		[email-masked]
	Osmand DeSouza		[email-masked]
	Hans Eriksson		[email-masked]
	Don Hoffman		[email-masked]
	Oliver Jones		[email-masked]
	Jim Knowles		[email-masked]
	Bill Manning		[email-masked]
	Kathleen Nichols	[email-masked]
	Jim Perchik		[email-masked]
	Eve Schooler		schooler@.isi.edu
	Henning Schulzrinne	[email-masked]
	Scott Stein		[email-masked]
	Thierry Turletti	[email-masked]
	Abel Weinrib		[email-masked] 

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