Subject: Session Control Protocol Survey for MMUSIC IETF 12/94

From: Ruth Lang <[email-masked]>
Date: Fri, 11 Nov 1994 17:02:09 -0800

The goal of the enclosed survey solicitation is twofold:

1) Gather information in order to solidify a set of functional
   requirements for session control.  These requirements will be
   reflected in an architecture document and/or functional
   requirements document to be written by the MMUSIC working group.

2) Serve as a comparative basis for the development of an experimental
   session control protocol by MMUSIC.

Therefore, we are soliciting descriptions of the Session Control
Protocols you have defined and developed.  Survey information will be
made available to the IETF community for review at
ftp://venera.isi.edu/confctrl and ftp://ws11.std.sri.com/pub/confctrl.

During the IETF MMUSIC session tentatively scheduled on Thursday,
December 8, 9:30a-12:00, we will review and discuss a summary of the
surveys received and work to solidify a set of session control
protocol requirements.

In filling out this survey, you may wish to refer to a glossary of
session control terms (ftp://ws11.std.sri.com/pub/confctrl/glossary),
and the architectural framework diagram contained in
ftp://venera.isi.edu/confctrl/minutes/ietf.3.93.

Please send your responses to one or all of [email-masked],
[email-masked], and [email-masked] by November 28, 1994.  Later
responses will be accepted, but may not be factored into the summary
we present at IETF.  If for some reason you are unable to complete
each question, please send whatever information you can provide.

Please post any questions or comments on the survey to us, with cc to
[email-masked].

Thane J. Frivold, [email-masked]
Ruth E. Lang, [email-masked]
----------------------------------------------------------------------------

Session Control Protocol Survey
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

Name of the Protocol (if any)
Technical point(s) of contact including email address(es)
and organization affiliation

General Description
-------------------

1) Between what components is the protocol used?  I.e., between media
   agents, between session managers, session manager to media agent,
   or other.

2) Describe, at a fairly high level, the characteristics of session
   control that are key to your protocol.  I.e., what is the protocol
   trying to achieve and what special problems does it solve.  E.g.,
   process coordination, resource negotiation, media synchronization,
   floor control, topology management, etc.

3) Describe, at a fairly high level, the characteristics of session
   control that you do not care about or have (un)intentionally
   ignored.  See examples in 3.

General Protocol Characteristics
--------------------------------

4) Is the representation ASCII or binary?

5) Is the paradigm request/response (client/server model),
   peer-to-peer, or other?

6) Is it asymmetric or symmetric (e.g. do initiator's have special
   privileges or state information)?  Are all messages sent to all
   participants or are some sent to a subset?

7) What transport protocol is used (TCP, UDP, multicast)?  Does it
   make use of other protocols such as RTCP?

8) Does your session control protocol rely on that protocol's model of
   transmission?  E.g., does it require reliable, ordered
   transmission or is multiparty state synchronization not a concern?

9) Briefly describe the addressing model, if any.  I.e., how are
   messages routed to peers?  Are they sent directly, are multicast
   groups used, is message content/registration used, or other?

Session Control Characteristics
-------------------------------

10) How are sessions are described?  What does a session description
    specify -- people, resources, scheduling information, etc.?
    Optionally, include an example session description.

11) Is the session description available and used outside of the
    context of the session control protocol?  If so, how
    (pre-scheduling, email-based initiation, etc.)?
		  
12) How is a session identified?  I.e., what is the session "handle"
    and to what extent is it globally unique?

13) Briefly describe the membership model and range of models
    supported.  Is the model open (potentially unknown participation
    and attendance -- lecture hall style), closed (well known and
    limited -- invitation only style), or other?

14) How are members named and/or identified?  Are email-style
    addresses used, numeric identifiers, etc.?

15) Briefly describe "what" is being controlled within a session.
    Does the protocol control routing, data flow (e.g., floor
    control, channel selection), reflectors, end-user applications,
    etc.?  Are these entities controlled in a centralized or
    distributed manner?

16) How is consensus achieved among parties exchanging this protocol?
    E.g., does initiator dictate policy, does a mismatch lead to
    failure, does negotiation occur when agreement can not be
    achieved?

17) What aspects of the conference are negotiable?  Members,
    protocols, data formats, resources, scheduling, policy, etc.?

18) What policies are implemented explicitly or implicitly (e.g., no
    latecomers permitted, only one video flow at a time, etc.)?  Is
    the choice of policy driven by system requirements, implementation
    constraints, resource limitations, etc?  Are the policies
    configurable?

Session Control Protocol Specifics
----------------------------------

19) What is the implementation status of the protocol (paper design,
    partially or fully implemented)?  What language was used to
    implement the protocol and how is it packaged (in a library,
    embedded in an application)?  Is the implementation freely
    available?

20) Describe, at a fairly high level, the basic directives of the
    protocol.  I.e., What are the protocol "commands" and what
    parameters are required?  If protocol uses a request-response model,
    indicate these pairs.  (If this information is contained in a
    publically-available paper or report, please provide a reference
    rather than detail here).

---

From: Ruth Lang <[email-masked]>
Date: Tue, 15 Nov 1994 11:07:50 -0800

Brian and Henning,

The permission problem on
ftp://ws11.std.sri.com/pub/confctrl/glossary.txt has been fixed.
Thanks for bringing it to my attention.

Regards,

Ruth Lang