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 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 To view the list Internet-Draft Shadow Directories, see http://www.ietf.org/shadow.html. 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] Internet Draft conf-policy-req February 24, 2003 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] Internet Draft conf-policy-req February 24, 2003 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 Petri Koskelainen [Page 3] Internet Draft conf-policy-req February 24, 2003 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 Petri Koskelainen [Page 4] Internet Draft conf-policy-req February 24, 2003 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] Internet Draft conf-policy-req February 24, 2003 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 Petri Koskelainen [Page 6] 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"] Petri Koskelainen [Page 7] Internet Draft conf-policy-req February 24, 2003 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. Petri Koskelainen [Page 8] Internet Draft conf-policy-req February 24, 2003 [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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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]