Mediactrl M. Dolly Internet-Draft AT&T Labs Intended status: Informational R. Even Expires: June 18, 2008 Polycom December 16, 2007 Media Server Control Protocol Requirements draft-ietf-mediactrl-requirements-02.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. 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 June 18, 2008. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract This document addresses the communication between an application server and media server. The current work in IETF working groups shows these logical entities but does not address the physical decomposition and the protocol between the entities. This document presents the requirements for a media server control protocol (MCP) that enables an application server to use a media Dolly & Even Expires June 18, 2008 [Page 1] Internet-Draft MCP Requirements December 2007 server. It will address the aspects of announcements, Interactive Voice Response and conferencing media services. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.1. Media Control Requirements . . . . . . . . . . . . . . . . 4 3.2. Media mixing Requirements . . . . . . . . . . . . . . . . . 6 3.3. IVR Requirements . . . . . . . . . . . . . . . . . . . . . 6 3.4. Operational Requirements . . . . . . . . . . . . . . . . . 7 4. IANA consideration . . . . . . . . . . . . . . . . . . . . . . 7 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 6. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . 7 7. Informative References . . . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 Intellectual Property and Copyright Statements . . . . . . . . . . 9 Dolly & Even Expires June 18, 2008 [Page 2] Internet-Draft MCP Requirements December 2007 1. Introduction The IETF conferencing framework in RFC 4353[CARCH] presents an architecture that is built of several functional entities. The framework document does not specify the protocols between the functional entities since it is considered out of scope. There is an interest to work on a protocol that will enable one physical entity, known as an Application Server (AS), that includes the conference/media policy server, the notification server and the focus to interact with one or more physical entities, called Media Server (MS), that serves as mixer or media server. The Media server can also be used for announcements and Interactive Voice Response (IVR) functions. An example of the decomposition of a media server and an application server is described in the media control framework document[mediactrl-fw]. This document presents the requirements for a media server control protocol (MCP) that enables an application server to use a media server. It will address the aspects of announcements, IVR and conferencing media services. The requirements are for the protocol and do not address the AS or MS functionality discussed in the media control framework. 2. Terminology The Media Server work uses, when appropriate, and expands on the terminology introduced in the conferencing framework[CARCH] and Centralized Conferencing (XCON) conferencing framework[xcon-framework]. The following additional terms are defined: Application Server (AS) - A functional entity that hosts one or more instances of a communications application. The application server may include the conference policy server, the focus and the conference notification server as defined in [CARCH]. It may include also communication applications that use IVR or announcements services. Media Server (MS) - The media server includes the mixer as defined in [CARCH]. The media server plays announcements, it process media streams for functions like DTMF detection and transcoding. The media server may also record media streams for supporting IVR functions Dolly & Even Expires June 18, 2008 [Page 3] Internet-Draft MCP Requirements December 2007 like announcing participants Media Resource Broker (MRB) - A logical entity that is responsible for both collection of appropriate published Media Server (MS) information and supplying of appropriate MS information to consuming entities. Notification - A notification is used when there is a need to report event related information from the MS to the AS. Request - A request is sent from the controlling entity, such as an Application Server, to another resource, such as a Media Server, asking that a particular type of operation be executed. Response - A response is used to signal information such as an acknowledgement or error code in reply to a previously issued request. 3. Requirements 3.1. Media Control Requirements The following are the media control requirements: REQ-MCP-01 - The MS control protocol shall enable one or more Application Servers to request media services from one or more media servers. REQ-MCP-02 The MS control protocol shall use a reliable transport protocol. REQ-MCP-03 - The applications supported by the protocol shall include Conferencing and Interactive Voice Response media services. Note: Though the protocol enables these services, the functionality is invoked through other mechanisms. REQ-MCP-04 - Media types supported in the context of the applications shall include audio, tones, text and video. Tones media include in band audio or RFC 4733 payload. REQ-MCP-05- The MS control protocol should allow, but must not require, a media resource broker (MRB) or intermediate proxy to exist with the Application Server and Media Server. Dolly & Even Expires June 18, 2008 [Page 4] Internet-Draft MCP Requirements December 2007 REQ-MCP-06 - On the MS control channel, there shall be requests to the MS, responses from the MS and notifications to the AS. REQ-MCP-07 - SIP/SDP shall be used to establish and modify media connections to a Media Server. REQ-MCP-08 - It should be possible to support a single conference spanning multiple Media Servers. Note: It is probable that spanning multiple MS can be accomplished by the AS and does not require anything in the protocol for the scenarios we have in mind. However, the concern is that if this requirement is treated too lightly, one may end up with a protocol that precludes its support. REQ-MCP-09 - It must be possible to split call legs individually or in groups away from a main conference on a given Media Server, without performing re-establishment of the call legs to the MS (e.g., for purposes such as performing IVR with a single call leg or creating sub-conferences, not for creating entirely new conferences). REQ-MCP-10 - The MS control protocol should be extendable, facilitating forward and backward compatibility. REQ-MCP-11 - The MS control protocol shall include security mechanisms. Since the solution need to support multiple AS controlling one MS it requires mechanisms to protect the MS resources used by one AS from another AS REQ-MCP-12 - During session establishment, there shall be a capability to negotiate parameters that are associated with media streams. This requirement should enable also an AS managing conference to specify the media streams allowed in the conference. REQ-MCP-13 - The AS shall be able to define operations that the MS will perform on streams like mute and gain control. REQ-MCP-14 - The AS shall be able to instruct the MS to play a specific announcement. REQ-MCP-15 - The AS shall be able to request the MS to create, delete, and manipulate a mixing, IVR or announcement session. Dolly & Even Expires June 18, 2008 [Page 5] Internet-Draft MCP Requirements December 2007 REQ-MCP-16 - The AS shall be able to instruct the MS to play announcements to a single user or to a conference mix. REQ-MCP-17 - The MS control protocol should enable the AS to ask the MS for session summary report. The report may include resources usage and quality metrics. REQ-MCP-18 - The MS shall be able to notify the AS of events received in the media stream if requested by AS. (Examples - STUN request, Flow Control, etc.) 3.2. Media mixing Requirements REQ-MCP-19 - The AS shall be able to define a conference mix, MS may offer different mixing topologies. The conference mix may be defined on a conference or user level. REQ-MCP-20 - The AS may be able to define a custom video layout built of rectangular sub windows. REQ-MCP-21 - For video the AS shall be able to map a stream to a specific sub-window or to define to the MS how to decide which stream will go to each sub window. REQ-MCP-22 - The MS shall be able to notify the AS who is the active speaker and who is being viewed in a conference. The speaker and the video source may be different, for example a person describing a video stream from a remote camera managed by a different user. REQ-MCP-23 - The MS shall be able to inform the AS which layouts it supports. REQ-MCP-24 - The MS control protocol should enable the AS to instruct the MS to record a specific conference mix. 3.3. IVR Requirements REQ-MCP-25 - The AS shall be able to instruct the MS to perform one or more IVR script and receive the results. The script may be in a server or contained in the control message. REQ-MCP-26 - The AS shall be able to manage the IVR session by sending requests to play announcements to the MS and receiving the response (e.g., DTMF). The IVR session flow in this case is handled by the AS by starting a next phase based on the response it receives from the MS on the current phase. Dolly & Even Expires June 18, 2008 [Page 6] Internet-Draft MCP Requirements December 2007 REQ-MCP-27 - The AS should be able to instruct the MS to record a short participant stream and play it back. This is not a recording requirement. 3.4. Operational Requirements These requirements may be applicable to the MRB but can be used by an AS if it has one to one connection to the MS. REQ-MCP-28 - The MS control protocol must allow the AS to audit the MS state, during an active session. REQ-MCP-29 - The MS shall be able to inform the AS about its status during an active session. 4. IANA consideration There are no IANA considerations. 5. Security Considerations The protocols that will meet the requirements described in this document will extend existing standards-track IETF protocols whose security properties are well understood. Required security properties will be based on the available security tools. 6. Acknowledgment This draft represents the work from two previous personal drafts, draft-dolly-xcon-mediacntrlframe-02 and draft-even-media-server-req-02. The authors would like to acknowledge the work of Gary Munson from AT &T Labs and James Rafferty from Cantata who helped with drafting draft-dolly-xcon-mediacntrlframe-02 on which this work is based. 7. Informative References [CARCH] Rosenberg, J., "A Framework for Conferencing with the Session Initiation Protocol (SIP)", RFC 4353, February 2006. [mediactrl-fw] Melanchuk, T., "An Architectural Framework for Media Server Control", draft-ietf-mediactrl-architecture-01 Dolly & Even Expires June 18, 2008 [Page 7] Internet-Draft MCP Requirements December 2007 (work in progress), November 2007. [xcon-framework] Barnes, M., "A Framework for Centralized Conferencing", draft-ietf-xcon-framework-10 (work in progress), November 2007. Authors' Addresses Martin Dolly AT&T Labs 200 Laurel Avenue Middletown, NJ 07748 USA Phone: Email: mdolly@att.com URI: Roni Even Polycom 94 Derech Em Hamoshavot Petach Tikva 49130 Israel Email: roni.even@polycom.co.il Dolly & Even Expires June 18, 2008 [Page 8] Internet-Draft MCP Requirements December 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. 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