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Internet Engineering Task Force
Internet Draft                                         Petri Koskelainen
                                                                   Nokia
draft-koskelainen-sipping-conf-policy-req-00.txt
February 24, 2003
Expires: August 2003


                Requirements for conference policy data

STATUS OF THIS MEMO

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   Internet-Drafts are working documents of the Internet Engineering
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Abstract

   The conference participants may communicate with the conference
   policy server, using a conference policy control protocol (CPCP)
   which is a strictly client-server transactional protocol. This
   document describes the requirements for conference policy data. Media
   policy related requirements are beyond the scope of this document.
   CPCP protocol is not mandatory and the only mechanism to manipulate
   conference policy data in a conference. For example, web interface
   can be used as well to perform conference policy manipulation.
   However, for automata a protocol is needed.









Petri Koskelainen                                             [Page 1]


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1 Introduction

   The conferencing framework document [1] describes the overall
   architecture, terminology, and protocol components needed for multi-
   party conferencing. It defines a logical function called a conference
   policy server which can store and manipulate rules associated with
   participation in a conference.  These rules include directives on the
   lifespan of the conference, who can and cannot join the conference,
   definitions of roles available in the conference and the
   responsibilities associated with those roles, and policies on who is
   allowed to request which roles.

   The conference policy control protocol (CPCP) is a client-server
   protocol that can be used by the participant to manipulate the rules
   associated with the conference.

   The conference policy is represented by a URI. There is a unique
   conference policy for each conference. The conference policy URI
   points to a conference policy server which can manipulate that
   conference policy.

   Conferencing framework describes also conference notification service
   that is a logical function provided by the focus. It means that the
   focus can act as a notifier, accepting subscriptions to the
   conference state.

   Note that CPCP is not the only mechanism to manipulate conference
   policy, but other mechanisms exists as well, such as Web interface.

   This document can be used with other documents, such as Conferencing
   framework document [1], and SIP call control - conferencing for user
   agents [2].

   Moreover, [4], [5], [6] give useful background information about
   conferencing and floor control.

1.1 Conventions of This Document

   In this document, the key words "MUST", "MUST NOT", "REQUIRED",
   "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
   and "OPTIONAL" are to be interpreted as described in RFC 2119 [3].

2 Terminology

   This document uses the definitions from [1].

   Additional definitions:




Petri Koskelainen                                             [Page 2]


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        ACL: Access Control List. Defines which users are eligible to
             join a conference. Each conference has its own ACL.

        Moderator: A special (privileged) role for a user that is
             allowed to manipulate conference policy and override policy
             decisions made by other users.

        Privilege: A privilege is a right to perform a manipulation
             operation for a conference. It is user permission such as
             "MODIFY ACL", "TERMINATE CONFERENCE", "INVITE USERS",
             "EJECT USERS", "MODIFY FLOOR POLICY", "MODIFY MEDIA
             POLICY", "HAND OFF A PRIVILEGE TO ANOTHER USER", "FLOOR
             CONTROL CHAIR".  (assuming that privileges are individual
             instead of group based e.g. senior-members have all
             privileges)

3 Integration with Floor Control

   Floor control is an optional feature often used by conferencing
   applications.  It enables applications or users to gain safe and
   mutually exclusive or non-exclusive input access to a shared object
   or resource. We define a floor as the temporary permission for a
   conference participant to access or manipulate a specific shared
   resource or group of resources.

   We assume that the ability of users to create floors is governed by
   the conference policy. Privileged conference user may use floor
   control protocol (see [7], [8]) to create floors.

   The conference policy defines who is allowed to create, change, and
   remove floors using the floor control protocol.

   Floor chair is also appointed using the floor control protocol when
   the floor is created.  Typically, only conference moderators are
   allowed to use these commands.

   The conference moderator can remove the floor at any time using floor
   control protocol (so that the resources are no longer floor-
   controlled), or change the floor chair or the floor parameters.

   The floor chair just controls the access to the floor, according to
   the floor policy, defined at a time when the floor is created.

4 Conference Policy Data Model

   Conference policy data is relative static. It is not updated
   frequently as e.g. participant list is not part of conference policy.
   Users with sufficient privileges are able to manipulate conference



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   policy.  For example, a user with sufficient privileges may
   manipulate conference's access control list by adding a user into the
   ACL white list.

   It is also assumed that the policy data server does not necessarily
   have a clock.  Therefore, conference policy data does not have any
   time-related policy attributes.

5 Conference Policy Requirements

   This section describes conference policy requirements.

5.1 Conference creation, termination and joining

   (Requirements A1-A7 apply better to CPCP rather than to policy data)

        REQ-A1: It MUST be possible to create a new conference at focus,
             resulting in a URI.

        REQ-A2: It MUST be possible to associate policy attributes to a
             conference URI.

        REQ-A3: It MUST be possible to reserve a conference URI from the
             focus for future use with or without associating policy
             attributes to it.

        REQ-A4: It MUST be possible for an user to fetch some or all
             components of conference policy from the focus (from the
             conference URI), during and before joining the conference.

        REQ-A5: It MUST be possible to delete the existing conference
             URI and release all resources associated with it.

        REQ-A6: It MUST be possible to terminate the conference instance
             but keep the conference URI and all policy attributes
             reserved.

        REQ-A7: It SHOULD be possible to join anonymously to the
             conference and still be able to send and receive data and
             private 1-to-1 SIP messages anonymously.

5.2 Manipulating general conference attributes

        REQ-B2: It MUST be possible to set and modify conference Subject
             that can be seen e.g. in web page, SDP s line or SIP
             Subject header.

        REQ-B3: It MUST be possible to set, modify and delete conference



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             URI display name.

        REQ-B4: It MUST be possible to set, modify and delete conference
             creator information (as is seen e.g. in SDP o line).

        REQ-B5: It MUST be possible to set, modify and delete conference
             URI link for more information (as used e.g. in SDP u line).

        REQ-B6: It MUST be possible to set, modify and delete conference
             host contact information (as used e.g. in SDP e and p
             lines).

        REQ-B7: It MUST be possible to set, modify and delete short
             conference session description (as used e.g. in SDP i
             line).  This can be per session or per media.

        REQ-B8: It MUST be possible to set, modify and delete max number
             of conference participants. This defines how many users at
             max can be present at the same time.

        REQ-B9: It MUST be possible to set whether the conference is
             public or hidden (if hidden, focus does not return
             description to outsiders for OPTIONS or other requests).

        REQ-B10: Conference policy MUST have an attribute that defines
             whether the conference is active or inactive. (If active,
             users can join etc).  [This is needed because start/end
             times are not used here]

        REQ-B11: It MUST be possible to give the list of invited users
             into the conference (dial-out case).

5.3 Authentication and Security

        REQ-C1: It MUST be possible to define the authentication
             mechanism, and passwords for user joins.

        REQ-C2: It MUST be possible to use sips: scheme as a conference
             URI.

        REQ-C3: It MUST be possible to define encryption keys for media
             data.  [OPEN ISSUE: Does this belong to media policy?]

5.4 Application and media manipulation

        REQ-D1:  It MUST be possible to assign and de-assign the users
             who are allowed to manipulate media policy.




Petri Koskelainen                                             [Page 5]


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5.5 ACL manipulation

        REQ-E1: It MUST be possible to add and delete users into and
             from ACL white list (allowed to join) and ACL black list
             (not allowed to join).

        REQ-E2: ACL conflicts MUST be solved in a well-defined way (e.g.
             what if user appears both in black list and in white list)
             e.g. by mandating the order in which ACL definitions are
             evaluated (e.g. most specific expression first).

        REQ-E3: It MUST be possible to use wildcards in ACL (such as
             *.company.com in white list).

        REQ-E4: It MUST be possible to allow and disallow anonymous and
             hidden joins to the conference.

5.6 Floor control

        REQ-F1: It MUST be possible to assign and de-assign the users
             who are allowed to manipulate floor policy. (Floor policy
             is manipulated by the floor control protocol itself).

5.7 Inviting and ejecting users

        REQ-G1: It MUST be possible to invite one or more users into the
             conference (including so called "mass invitation"
             operation).

        REQ-G2: It MUST be possible eject one or more users from the
             conference (including so called "mass ejection" operation).

5.8 User Privileges

        REQ-H1: It MUST be possible to give a privilege to a user.  (A
             privilege may be operation, such as right to expel, right
             to modify conference ACL, right to hand off all or some
             privileges to another user).

        REQ-H2: It MUST be possible to remove a privilege from a user.

        REQ-H3: It MAY be possible to support user privilege groups
             (e.g. senior-members) and to group privileges together,
             such as senior-members can eject users and manipulate ACL.

        REQ-H4: It MAY be possible that default privileges (e.g. only
             the creator can delete conference) are defined by the
             Conference Policy Control Protocol that can be changed by



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Internet Draft              conf-policy-req            February 24, 2003


             the conference policy.

        REQ-H5: It MUST be possible to authorize users who have the
             right to subscribe to specific events, such as ACL changes.

        REQ-H6: It MAY be possible request new privileges from the
             conference policy server via CPCP.

        REQ-H7: It SHOULD be possible to define who is allowed to
             subscribe to conference related events.

        REQ It MAY be possible that default privileges are defined for
             new conference, such as conference creator has all
             privileges available and others do not have have any of
             them.

6 Notifications and Subscriptions

   New SIP event packages may be needed.  For example, conference owner
   (or a user with sufficient privileges) may subscribe to the
   conference management event, and get notified when there is a need to
   do policy manipulation, such as ACL manipulation for on-going join
   attempt.

7 Possible Solutions

   This document is primarily a requirements document, and does not aim
   to provide a protocol or policy data format for meeting the
   requirements defined here. Solutions such as SOAP, XML/RPC and ACAP
   can be utilized.  Moreover, the use of encoding formats such as SDP,
   SDP-NG, iCal, and vCard can be investigated.

8 Open Issues

        o Whether time-related policy data attributes are needed, e.g.
          for conference start/end times. Even if absolute times are not
          needed, it may be useful to have relative times (e.g. max time
          2 hours).  Conference may be created in advance, put to
          inactive state and activated when needed. This needs more
          thinking.

        o Should conferece policy include any bandwidth related
          attributes (e.g. per media, per user or per conference)?

9 Changes from previous version

   CPCP requirements section [This section may be later extracted to
   separate internet-draft "Requirements for policy control protocol"]



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        REQ-CP-1: Protocol behaviour:  CPCP protocol SHOULD be a
             reliable client-server protocol. Hence, it SHOULD have a
             positive response indicating that the request has been
             received, or error response if an error has occurred.  The
             sending UA takes care of retransmission in the case of
             packet loss.

        REQ-CP-2: Manipulations of the policy collection MUST exhibit
             the ACID property; that is, they MUST be atomic, be
             consistent, durable, and operate independently.

        REQ-CP-3: It MAY be possible for the client to batch multiple
             operations (such as add a user to ACL black list, or remove
             a user from ACL white list) into a single request that is
             processed atomically.

        REQ-CP-4: It MUST be possible for the server to authenticate the
             client.

        REQ-CP-5: It MUST be possible for the client to authenticate the
             server.

        REQ-CP-6: It MUST be possible for message integrity to be
             ensured between the client and the server.

        REQ-CP-7: It MUST be possible for privacy to be ensured between
             the client and server.

10 Acknowledgements

   The author would like to thank Rohan Mahy, Jonathan Rosenberg, Roni
   Even, Orit Levin, Alan Johnston, Joerg Ott and others for their
   comments.

11 Authors' Addresses

   Petri Koskelainen
   Nokia
   Visiokatu 1,
   33720 Tampere,
   Finland
   e-mail: petri.koskelainen@nokia.com

12 Normative References

   [1] J. Rosenberg, "A framework for conferencing with the session
   initiation protocol," internet draft, Internet Engineering Task
   Force, Feb. 2003.  Work in progress.



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   [2] A. Johnston,O. Levin, "Session Initiation Protocol Call Control -
   Conferencing for User Agents", internet draft, Internet Engineering
   Task Force, Feb. 2003.  Work in progress.

   [3] S. Bradner, "Key words for use in rfcs to indicate requirement
   levels," RFC 2119, Internet Engineering Task Force, Mar. 1997.

13 Informative References

   [4] C. Bormann, D. Kutscher, J. Ott, and D. Trossen, "Simple
   conference control protocol service specification," internet draft,
   Internet Engineering Task Force, Mar. 2001.  Work in progress.

   [5] P. Koskelainen, H. Schulzrinne, and X. Wu, "Additional
   requirements to conferencing," internet draft, Internet Engineering
   Task Force, Apr. 2002.  Work in progress.

   [6] H. Schulzrinne. P. Koskelainen and X. Wu, "A sip-based conference
   control framework," in NOSSDAV, (Miami, Florida), May 2002.

   [7] P. Koskelainen, H. Schulzrinne, and J. Ott, "Requirements for
   floor control," internet draft, Internet Engineering Task Force, Nov.
   2002.  Work in progress.

   [8] X. Wu et al., "Use of session initiation protocol (SIP) and
   simple object access protocol (SOAP) for conference floor control,"
   internet draft, Internet Engineering Task Force, Jan. 2003.  Work in
   progress.

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   this standard. Please address the information to the IETF Executive
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Petri Koskelainen                                            [Page 10]


                           Table of Contents



   1          Introduction ........................................    2
   1.1        Conventions of This Document ........................    2
   2          Terminology .........................................    2
   3          Integration with Floor Control ......................    3
   4          Conference Policy Data Model ........................    3
   5          Conference Policy Requirements ......................    4
   5.1        Conference creation, termination and joining ........    4
   5.2        Manipulating general conference attributes ..........    4
   5.3        Authentication and Security .........................    5
   5.4        Application and media manipulation ..................    5
   5.5        ACL manipulation ....................................    6
   5.6        Floor control .......................................    6
   5.7        Inviting and ejecting users .........................    6
   5.8        User Privileges .....................................    6
   6          Notifications and Subscriptions .....................    7
   7          Possible Solutions ..................................    7
   8          Open Issues .........................................    7
   9          Changes from previous version .......................    7
   10         Acknowledgements ....................................    8
   11         Authors' Addresses ..................................    8
   12         Normative References ................................    8
   13         Informative References ..............................    9






















Petri Koskelainen                                             [Page 1]


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