Transport Area P. Koskelainen
Internet-Draft Nokia
Expires: December 22, 2003 June 23, 2003
Requirements for Conference Policy Control Protocol
draft-koskelainen-xcon-cpcp-reqs-00
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
Task Force (IETF), its areas, and its working groups. Note that other
groups may also distribute working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at http://
www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on December 22, 2003.
Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved.
Abstract
The conference policy server allows clients to manipulate and
interact with the conference policy. One mechanism to manipulate the
policy is to use conference policy control protocol (CPCP). This
document gives the requirements for CPCP.
Koskelainen Expires December 22, 2003 [Page 1]
Internet-Draft CPCP-req June 2003
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions Used in This Document . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Integration with Floor Control . . . . . . . . . . . . . . . . 6
5. Conference Policy Data Model . . . . . . . . . . . . . . . . . 7
6. CPCP Requirements . . . . . . . . . . . . . . . . . . . . . . 8
6.1 Conference creation, termination and joining . . . . . . . . . 8
6.2 Manipulating general conference attributes . . . . . . . . . . 8
6.3 Authentication and Security . . . . . . . . . . . . . . . . . 9
6.4 Application and media manipulation . . . . . . . . . . . . . . 9
6.5 ACL manipulation . . . . . . . . . . . . . . . . . . . . . . . 9
6.6 Floor control . . . . . . . . . . . . . . . . . . . . . . . . 10
6.7 Inviting and ejecting users . . . . . . . . . . . . . . . . . 10
6.8 User Privileges . . . . . . . . . . . . . . . . . . . . . . . 10
6.9 General Protocol Requirements . . . . . . . . . . . . . . . . 11
7. Notifications and Subscriptions . . . . . . . . . . . . . . . 12
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13
Normative References . . . . . . . . . . . . . . . . . . . . . 14
Informative References . . . . . . . . . . . . . . . . . . . . 15
Author's Address . . . . . . . . . . . . . . . . . . . . . . . 15
Intellectual Property and Copyright Statements . . . . . . . . 16
Koskelainen Expires December 22, 2003 [Page 2]
Internet-Draft CPCP-req June 2003
1. Introduction
The conferencing framework document [3] describes the overall
architecture, terminology, and protocol components needed for multi-
party conferencing. It defines a logical function called a conference
policy server (CPS) 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 users 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 [3].
Moreover, [4] and [6] give useful background information about
conferencing and floor control.
Koskelainen Expires December 22, 2003 [Page 3]
Internet-Draft CPCP-req June 2003
2. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119.
Koskelainen Expires December 22, 2003 [Page 4]
Internet-Draft CPCP-req June 2003
3. Terminology
This document uses the definitions from [3].
Additional definitions:
ACL
Access control list (ACL) defines users who can join to a
conference. Users may have allow, blocked or pending status in
the list. 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.
Floor control
Floor control is a mechanism that enables applications or users
to gain safe and mutually exclusive or non-exclusive access to
the shared object or resource in a conference.
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" (assuming that privileges are individual instead
of group based e.g. senior-members have all privileges)
Koskelainen Expires December 22, 2003 [Page 5]
Internet-Draft CPCP-req June 2003
4. 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 e.g. [5]) or some other mechanism 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.
Koskelainen Expires December 22, 2003 [Page 6]
Internet-Draft CPCP-req June 2003
5. 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
policy. For example, a user with sufficient privileges may
manipulate conference's access control list by adding a user into the
ACL white list.
Koskelainen Expires December 22, 2003 [Page 7]
Internet-Draft CPCP-req June 2003
6. CPCP Requirements
This section describes conference policy requirements.
6.1 Conference creation, termination and joining
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 a user to fetch some or all
components of the conference policy for a given 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 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.
6.2 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 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.
Koskelainen Expires December 22, 2003 [Page 8]
Internet-Draft CPCP-req June 2003
REQ-B8: It MAY be possible to set, modify and delete the parameter
for max number of conference participants. This defines how many
users at max can be present at the same time.
OPEN ISSUE: This is typical parameter in PSTN conferences, but does
this make sense in IP world (and with different codecs) ?
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 if start/end times are not used]
REQ-B11: It MUST be possible to give the list of invited users into
the conference (dial-out case).
REQ-B-12: It MUST be possible to set, modify and delete conference
Keywords. (This may be useful e.g. for search engines).
6.3 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?]
6.4 Application and media manipulation
REQ-D1: It MUST be possible to assign and de-assign the users who
are allowed to manipulate media policy.
6.5 ACL manipulation
REQ-E1: It MUST be possible to add and delete users into and from ACL
white list (allowed to join), ACL black list (not allowed to join)
and ACL pending list (further authorization needed).
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 user part in ACL
Koskelainen Expires December 22, 2003 [Page 9]
Internet-Draft CPCP-req June 2003
(such as sip:*@example.com in white list).
REQ-E4: It MUST be possible to allow and disallow anonymous and
hidden joins to the conference.
REQ-E5: ACL MUST have default policy for those users that no matching
rule is found.
6.6 Floor control
REQ-F1: It MUST be possible to assign and de-assign the users who are
allowed to manipulate floor policy.
6.7 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).
6.8 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 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-H8: It MAY be possible that default privileges are defined for
Koskelainen Expires December 22, 2003 [Page 10]
Internet-Draft CPCP-req June 2003
new conference, such as conference creator has all privileges
available and others do not have have any of them.
6.9 General Protocol Requirements
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.
Koskelainen Expires December 22, 2003 [Page 11]
Internet-Draft CPCP-req June 2003
7. Notifications and Subscriptions
It is necessary to have a notification mechanism in addition to CPCP,
e.g. SIP. 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. It is also necessary to
authenticate who is allowed to subscribe to these events.
Koskelainen Expires December 22, 2003 [Page 12]
Internet-Draft CPCP-req June 2003
8. Acknowledgements
The author would like to thank Eric Burger, Xiaotao Wu, Henning
Schulzrinne, Simo Veikkolainen and IETF conferencing design team for
their feedback.
Koskelainen Expires December 22, 2003 [Page 13]
Internet-Draft CPCP-req June 2003
Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", RFC 2119, BCD 14, March 1997.
[2] Rosenberg et al., J., "SIP: Session Initiation Protocol", RFC
3261, June 2002.
[3] Rosenberg, J., "A Framework for Conferencing with the Session
Initiation Protocol",
draft-rosenberg-sipping-conferencing-framework-01 (work in
progress), February 2003.
Koskelainen Expires December 22, 2003 [Page 14]
Internet-Draft CPCP-req June 2003
Informative References
[4] Koskelainen, P., Schulzrinne, H. and X. Wu, "Additional
Requirements to Conferencing", October 2002.
[5] Wu, X., Schulzrinne, H. and P. Koskelainen, "Use of SIP and SOAP
for conference floor control", January 2003.
[6] Koskelainen, P., Schulzrinne, H. and X. Wu, "A sip-based
conference control framework", Nossdav'2002 Miami Beach, May
2002.
Author's Address
Petri Koskelainen
Nokia
P.O. Box 100 (Visiokatu 1)
Tampere FIN-33721
Finland
EMail: petri.koskelainen@nokia.com
Koskelainen Expires December 22, 2003 [Page 15]
Internet-Draft CPCP-req June 2003
Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP-11. Copies of
claims of rights made available for publication and any assurances of
licenses to be made available, or the result of an attempt made to
obtain a general license or permission for the use of such
proprietary rights by implementors or users of this specification can
be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive
Director.
Full Copyright Statement
Copyright (C) The Internet Society (2003). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assignees.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
Koskelainen Expires December 22, 2003 [Page 16]
Internet-Draft CPCP-req June 2003
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
Koskelainen Expires December 22, 2003 [Page 17]