SIPREC P. Kyzivat Internet-Draft M. Yan Intended status: Informational Huawei Expires: February 5, 2015 S. Romano University of Napoli August 4, 2014 Multimedia Conference Recording Use Cases and Requirements draft-kyzivat-siprec-conference-use-cases-02 Abstract The current work of SIPREC will soon finish. As conferences are the key requirement for some environments, it is worth to explore several extensions and additional functionality to support multimedia conference recording. SIPREC is not sufficient to record all the conference sessions via certain interactive media channels, like multi-user chat or screen sharing. This draft tries to show the use cases for multimedia conference recording and the requirements for how to work well under SIPREC mechanism. The requirements ask for extensions to SIP that will manage delivery of RTP media sessions, including content media defined by [RFC4796] , and MSRP media sessions to a recording device. The recorded media sessions are all SIP-based. Requirements Language 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 [RFC2119] . Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." Kyzivat, et al. Expires February 5, 2015 [Page 1] Internet-Draft Use Cases for Multimedia Conf Rec August 2014 This Internet-Draft will expire on February 5, 2015. Copyright Notice Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Multimedia Conference Recording Overview . . . . . . . . . . 3 3. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4.1. MSRP Instant Message Stream Recording . . . . . . . . . . 5 4.2. Screen Sharing Stream Recording . . . . . . . . . . . . . 5 4.3. Application Sharing Stream Recording . . . . . . . . . . 6 4.4. Document Sharing Stream Recording . . . . . . . . . . . . 6 4.5. Audio/Video Conference Recording . . . . . . . . . . . . 6 4.6. Chat Conference Recording . . . . . . . . . . . . . . . . 7 4.7. Multimedia conference Recording . . . . . . . . . . . . . 7 5. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 7 5.1. REQ-001 . . . . . . . . . . . . . . . . . . . . . . . . . 7 5.2. REQ-002 . . . . . . . . . . . . . . . . . . . . . . . . . 7 5.3. REQ-003 . . . . . . . . . . . . . . . . . . . . . . . . . 7 5.4. REQ-004 . . . . . . . . . . . . . . . . . . . . . . . . . 8 5.5. REQ-005 . . . . . . . . . . . . . . . . . . . . . . . . . 8 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 7. Security Considerations . . . . . . . . . . . . . . . . . . . 8 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 8.1. Normative References . . . . . . . . . . . . . . . . . . 8 8.2. Informative References . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 1. Introduction In general, a basic video conference has participants with video channels, audio channels and DTMF ability. An advanced multimedia conference would have extended channels like text, interactive text Kyzivat, et al. Expires February 5, 2015 [Page 2] Internet-Draft Use Cases for Multimedia Conf Rec August 2014 and presentation graphics [RFC4597] . These extended channels recording have the same strong needs as audio or video, especially in some conference use cases. The conference's host and participants, even nonparticipants, would like to play back the recordings in real- time or non-real-time for different purposes, like editing summary, reviewing outlines or monitoring process. The recordings should have the ability to reconstruct the conference richly, with adequate media and metadata recorded, which are not only audio/video but also IM and shared content. Such an exhaustive reconstruction could give audiences more information and a better experience. The recorded sessions can be any RTP media sessions, including the content media (as defined by [RFC4796] ) transferred as video stream, and MSRP media session which is SIP based media session. 2. Multimedia Conference Recording Overview There is one use case (use case 11) covering the recording of a multi-channel and multimedia session in the existing use case document [RFC6341] . Aside from audio, video, DTMF (as defined by [RFC4733] ) and text (as defined by [RFC4103] ), it does not include other interactive channels. The limitations to the multi-channel types leads to poor support for recording multimedia conferences. A multimedia conference has various channels, including audio, video, IM, data sharing (screen/document/application), etc. SIPREC is mostly capable of recording any sort of RTP media sessions, including voice, video, DTMF (as defined by [RFC4733] ) and text [RFC6341] with SDP negotiation [I-D.ietf-siprec-protocol] and certain metadata [I-D.ietf-siprec-metadata] . But it is not evident how to support the remaining media, like multi-user chat or screen sharing. Multi-user chat is one of key cases about the IM session in multimedia conference. A multi-user chat or simple-chat session is to handle the media to relay instant messages received from one participant to the rest of the participants in the conference [I-D.ietf-simple-chat] , especially for the MSRP session which is a SIP based system. The host and participants in a conference might start MSRP sessions among each other for public group chat, sidebar chat or whisper chat. These MSRP content could be replicated by SRC (might be the MSRP switch or certain MSRP replay or MSRP client) to deliver to SRS via special RS channel(s). The replicated content could be the Message/CPIM message that contains text, HTML and images, etc. The document only considers the SIP based system, recording XMPP based IM in CS is out of the scope. The data sharing session, known as content sharing or content streams as well, in a multimedia conference's CS has functionality like screen sharing, application sharing, document sharing, etc. These data streams could be managed as still images (snapshots with Kyzivat, et al. Expires February 5, 2015 [Page 3] Internet-Draft Use Cases for Multimedia Conf Rec August 2014 increments) or as dynamic streams (video streams) to carry details like slide presentation, annotations, direct editing or page turning. Especially, the screen sharing would have different ways to get its data streams, like the video streams directly offered from VGA port or encoded/decoded by an application on peer's client, or turned from multiple screenshots, or even the still images carried by MSRP channels. One way for a conference focus/mixer to record a conference is introduced in [I-D.ietf-siprec-architecture] . This defines how the conference focus works as a SRC to deliver RTP streams and associate recording metadata with SRS. It may choose the recording RTP stream type, separated or mixed. There are more details about how to use SDP, RTP for recording by participant or by media type in [I-D.ietf-siprec-protocol] . The focus may setup different recording sessions for different media streams recorded separately, or one recording session for a mixed media stream created by the SRC, or even multiplexing different media streams in a single RTP recording session [I-D.ietf-siprec-protocol] . But more is needed to support other media streams in a multimedia conference. There is need for MSRP switch/relay/client as SRC to replicate MSRP sessions to the recorder, with a new "media stream" type in RS for delivering MSRP based streams or contents. There is another need for a new type of metadata to indicate when media streams are being used to represent screen/application/data sharing sessions, distinct from the main video streams. There is also need of a mechanism for the SRC to bound the number of media streams to be recorded, especially when the participants number in a conference is extremely large. The document does not include recording any of the extended session attributes being defined by the CLUE WG. 3. Definitions Instant Message Stream: instant message stream refers to the streams transferred by messages between users in near real-time [RFC3248] . Data Sharing: Data sharing is to use a content channel for collaboratively working on documents, files, images, desktops, etc in real time. It is also called as content sharing, including application sharing, screen sharing, document sharing, etc. Application Sharing: application sharing is the sharing of the graphical user-interface of an application amongst multiple users simultaneously in real time. The slide sharing could be one special case. Kyzivat, et al. Expires February 5, 2015 [Page 4] Internet-Draft Use Cases for Multimedia Conf Rec August 2014 Screen Sharing: screen sharing is the sharing of a computer desktop amongst multiple users simultaneously in real time, also called desktop sharing. Comparing to application sharing, which is always a single one, screen sharing is for the whole screen. Document Sharing: document sharing is the sharing to help multiple users work simultaneously on a single document or file to achieve a single final version. It is also called file sharing or document collaboration. Audio/Video Conference: Audio/video conference is one sort of various conferences. In SIP, an audio/video conference is an instance of a multi-party conversation that matches the definition in [RFC4353] and the framework in [RFC5239] , with the media channels as audio and video. Chat Conference: a synonym for a multi-party chat conference [I-D.ietf-simple-chat] . Multimedia Conference: multimedia conference is the multi-party conversation including any combination of different media types such as audio, video, text, interactive text, or presentation graphics [RFC4597] . 4. Use cases 4.1. MSRP Instant Message Stream Recording Use Case 1: MSRP Instant Message Stream Recording. Instant message is the function offered to chat between/among peers. There are page mode and session mode ( MSRP [RFC6914] ). Here we are concerned with instant message sessions in the context of a point to point call using session mode, which treats the MSRP instant message session as a media type. For example, in a call center or emergency (first-responder) center, a customer could use the web client to start a chat with an agent about his questions or describing the situation happened around him. Call center or emergency center would need to record those chat sessions between customers and agents. 4.2. Screen Sharing Stream Recording Use Case 2: Screen Sharing Stream Recording. Kyzivat, et al. Expires February 5, 2015 [Page 5] Internet-Draft Use Cases for Multimedia Conf Rec August 2014 This is also well known as desktop sharing or remote sharing between peers. This function could be also used in a point to point call directly. In an enterprise, the softphone calls between colleagues would choose screen sharing to illustrate their views clearly if the voice discussing is not enough. The enterprise would ask to record those screen sharing sessions for security check. Another example is the remote education training, which needs to record the screen to keep track of the whole training class. The state of the shared screen is recorded as video (and possibly audio) media, with metadata indicating that the stream represents screen sharing. 4.3. Application Sharing Stream Recording Use Case 3: Application Sharing Stream Recording. Users would choose application sharing instead of screen sharing to avoid exposing the privacy content on their computer desktop, when have the point-to-point call with others or have a conference call. And the recorded streams are the content of applications shown in CS. The state of the application window is recorded as video (and possibly audio) media, with metadata indicating that the stream represents application sharing. 4.4. Document Sharing Stream Recording Use Case 4: Document Sharing Stream Recording. Users would work on one document simultaneously in real time. The content of document would be recorded (which is close to use case 3). The state of the document sharing window is recorded as video media, with metadata indicating that the stream represents data sharing. 4.5. Audio/Video Conference Recording Use Case 5: audio/video conference Recording. The recording for audio/video conference is basic. All the channels in a conference would be recorded as one mixed stream or as separate streams by participants. It has been supported by current SIPREC mechanism. Kyzivat, et al. Expires February 5, 2015 [Page 6] Internet-Draft Use Cases for Multimedia Conf Rec August 2014 4.6. Chat Conference Recording Use Case 6: chat conference Recording. There is another Conference type, known as multi-user chat conference or chat-rooms. The chat conference would have participants in a conference to chat or text each other with nicknames and provide private chat using the Message Session Relay Protocol (MSRP) [I-D.ietf-simple-chat] . In this case, there would be a need to record the chat content and details like nicknames. 4.7. Multimedia conference Recording Use Case 7: Multimedia conference Recording. This is a special use case to indicate the multimedia conference recording environment. When there is a common education class or skill training conference, the audiences who are not in the conference session would prefer replaying the conference in real-time with professor or lecturer's voice with their slides, better include the video of if available. The recording of this education conferences need to record audio, video from hosts and data sharing of theirs. While the audiences(out-conference) need to know what the audiences(in-conference) feedback to the training, they might also want to know what those audiences(in-conference) have been discussing in IM session. Thus the recording need record the IM sessions. 5. Requirements 5.1. REQ-001 REQ-001: The mechanism MUST support recording of MSRP media sessions. This requirement derives from use cases 1,6,7. 5.2. REQ-002 REQ-002: The mechanism MUST support recording of screen sharing using audio and video media. This requirement derives from use cases 2,7. 5.3. REQ-003 REQ-004: The mechanism MUST support recording of application sharing using audio and video. This requirement derives from use cases 3,7. Kyzivat, et al. Expires February 5, 2015 [Page 7] Internet-Draft Use Cases for Multimedia Conf Rec August 2014 5.4. REQ-004 REQ-003: The mechanism MUST support recording of document sharing using video media. This requirement derives from use cases 4,7. 5.5. REQ-005 REQ-005: The mechanism MUST support metadata or SDP to identify media streams used to record screen/application/document sharing. This requirement derives from use cases 2,3,4,7. 6. IANA Considerations This document contains no IANA considerations. 7. Security Considerations Not explicitly covered in this version. 8. References 8.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, June 2002. [RFC6341] Rehor, K., Portman, L., Hutton, A., and R. Jain, "Use Cases and Requirements for SIP-Based Media Recording (SIPREC)", RFC 6341, August 2011. [I-D.ietf-siprec-architecture] Hutton, A., Portman, L., Jain, R., and K. Rehor, "An Architecture for Media Recording using the Session Initiation Protocol", draft-ietf-siprec-architecture-12 (work in progress), February 2014. [I-D.ietf-siprec-protocol] Portman, L., Lum, H., Eckel, C., Johnston, A., and A. Hutton, "Session Recording Protocol", draft-ietf-siprec- protocol-13 (work in progress), July 2014. Kyzivat, et al. Expires February 5, 2015 [Page 8] Internet-Draft Use Cases for Multimedia Conf Rec August 2014 [I-D.ietf-siprec-metadata] R, R., Ravindran, P., and P. Kyzivat, "Session Initiation Protocol (SIP) Recording Metadata", draft-ietf-siprec- metadata-15 (work in progress), February 2014. [I-D.kyzivat-siprec-webconf-use-case] Kyzivat, P. and M. Yan, "Web Conference Recording Use Case", draft-kyzivat-siprec-webconf-use-case-00 (work in progress), May 2013. [I-D.ietf-simple-chat] Niemi, A., Garcia, M., and G. Sandbakken, "Multi-party Chat Using the Message Session Relay Protocol (MSRP)", draft-ietf-simple-chat-18 (work in progress), January 2013. 8.2. Informative References [RFC3248] Armitage, G., Carpenter, B., Casati, A., Crowcroft, J., Halpern, J., Kumar, B., and J. Schnizlein, "A Delay Bound alternative revision of RFC 2598", RFC 3248, March 2002. [RFC4103] Hellstrom, G. and P. Jones, "RTP Payload for Text Conversation", RFC 4103, June 2005. [RFC4353] Rosenberg, J., "A Framework for Conferencing with the Session Initiation Protocol (SIP)", RFC 4353, February 2006. [RFC4597] Even, R. and N. Ismail, "Conferencing Scenarios", RFC 4597, August 2006. [RFC4733] Schulzrinne, H. and T. Taylor, "RTP Payload for DTMF Digits, Telephony Tones, and Telephony Signals", RFC 4733, December 2006. [RFC4796] Hautakorpi, J. and G. Camarillo, "The Session Description Protocol (SDP) Content Attribute", RFC 4796, February 2007. [RFC4975] Campbell, B., Mahy, R., and C. Jennings, "The Message Session Relay Protocol (MSRP)", RFC 4975, September 2007. [RFC5239] Barnes, M., Boulton, C., and O. Levin, "A Framework for Centralized Conferencing", RFC 5239, June 2008. Kyzivat, et al. Expires February 5, 2015 [Page 9] Internet-Draft Use Cases for Multimedia Conf Rec August 2014 [RFC6914] Rosenberg, J., "SIMPLE Made Simple: An Overview of the IETF Specifications for Instant Messaging and Presence Using the Session Initiation Protocol (SIP)", RFC 6914, April 2013. Authors' Addresses Paul H. Kyzivat Huawei Email: pkyzivat@alum.mit.edu Michael Yan Huawei Email: michael.yan@huawei.com Simon Pietro Romano University of Napoli Email: spromano@unina.it Kyzivat, et al. Expires February 5, 2015 [Page 10]