Network Working Group M. Westerlund Internet-Draft P. Frojdh Intended status: Informational Ericsson Expires: November 9, 2009 May 08, 2009 SDP and RTSP extensions defined for 3GPP Packet-switched Streaming Service and Multimedia Broadcast/Multicast Service draft-westerlund-mmusic-3gpp-sdp-rtsp-07 Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and 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 November 9, 2009. Copyright Notice Copyright (c) 2009 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 in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Abstract The Packet-switched Streaming Service (PSS) and the Multimedia Broadcast/Multicast Service (MBMS) defined by 3GPP use SDP and RTSP Westerlund & Frojdh Expires November 9, 2009 [Page 1]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 with some extensions. This document provides information about these extensions and registers the RTSP and SDP extensions with IANA. 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]. Westerlund & Frojdh Expires November 9, 2009 [Page 2]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 Table of Contents 1. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Glossary . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Applicability Statement . . . . . . . . . . . . . . . . . . . 5 4. PSS SDP Extensions . . . . . . . . . . . . . . . . . . . . . . 6 4.1. Video Buffering Attributes . . . . . . . . . . . . . . . . 6 4.2. Video Frame Size Attribute . . . . . . . . . . . . . . . . 7 4.3. Integrity Protection Configuration Attributes . . . . . . 7 4.4. The Alternative Attributes . . . . . . . . . . . . . . . . 7 4.5. Adaptation Attribute . . . . . . . . . . . . . . . . . . . 8 4.6. Quality of Experience Attribute . . . . . . . . . . . . . 8 4.7. Asset Information Attribute . . . . . . . . . . . . . . . 8 5. MBMS SDP Extensions . . . . . . . . . . . . . . . . . . . . . 8 5.1. MBMS Bearer Mode Declaration Attribute . . . . . . . . . . 9 5.2. FEC Flow ID Attribute . . . . . . . . . . . . . . . . . . 9 5.3. MBMS Repair Attribute . . . . . . . . . . . . . . . . . . 9 5.4. SDP Protocol Identifiers for FEC . . . . . . . . . . . . . 9 5.4.1. RTP Protocol Identifiers . . . . . . . . . . . . . . . 9 5.4.2. FEC Repair Data Identifier . . . . . . . . . . . . . . 10 5.5. Video Buffering Attribute . . . . . . . . . . . . . . . . 10 6. SDP Offer/Answer Consideration . . . . . . . . . . . . . . . . 10 7. PSS RTSP Extensions . . . . . . . . . . . . . . . . . . . . . 10 7.1. 3GPP-Link-Char Header . . . . . . . . . . . . . . . . . . 10 7.2. 3GPP-Adaptation Header . . . . . . . . . . . . . . . . . . 11 7.3. 3GPP-QoE-Metrics Header . . . . . . . . . . . . . . . . . 11 7.4. 3GPP-QoE-Feedback Header . . . . . . . . . . . . . . . . . 11 7.5. Video Buffer Headers . . . . . . . . . . . . . . . . . . . 11 7.6. Integrity Protection . . . . . . . . . . . . . . . . . . . 12 7.7. RTSP URI Extension . . . . . . . . . . . . . . . . . . . . 12 7.8. Fast Start-up and Content Switching . . . . . . . . . . . 12 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 8.1. SDP Registrations . . . . . . . . . . . . . . . . . . . . 13 8.2. RTSP Registrations . . . . . . . . . . . . . . . . . . . . 18 9. Security Considerations . . . . . . . . . . . . . . . . . . . 20 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 21 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 21 11.1. Normative References . . . . . . . . . . . . . . . . . . . 21 11.2. Informative References . . . . . . . . . . . . . . . . . . 22 11.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 22 Westerlund & Frojdh Expires November 9, 2009 [Page 3]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 1. Definitions 1.1. Glossary 3GP: 3GPP file format, a multi-media file format based on the ISO base media file format, existing in different profiles intended for multimedia messages, direct playback on clients, progressive download, usage on servers to deliver on-demand multi-media sessions in PSS, or servers sending MBMS sessions. 3GPP: Third Generation Partnership Project, see www.3gpp.org for more information about this organization. FEC: Forward Error Correction MBMS: Multimedia Broadcast/Multicast Service, a service defined by 3GPP that utilizes broadcast or multicast technologhy in combination with unicast for delivery of a wide range of content to mobile terminals. PSS: Packet-switched Streaming Service, a unicast-based streaming service for delivery of on-demand or live streaming multi-media content to mobile terminals. RTSP: Time Streaming Protocol, see [RFC2326]. SDP: Session Description Protocol, see [RFC4566]. SRTP: Secure Real-time Transport Protocol, see [RFC3711]. QoE: Quality of Experience, the quality level of the the user experience of a service. In PSS this is estimated by a combination of application-level metrics. QoS: Quality of Service, the quality (properties) that the network provides toward the upper layer service. 2. Introduction 3GPP has specified the Packet-switched Streaming Service (PSS) that uses both RTSP [RFC2326] and SDP [RFC4566]. The service is specified in technical specifications TS 26.233 [PSS-233] and TS 26.234 [PSS-234] in Release 4 and later releases. The basic service defined in Release 4 is enhanced in Release 5 with capability exchange and in Release 6 with a number of features, such as adaptation, digital rights management, progressive download as well as a streaming server file-format defined in [PSS-3GP]. Fast start-up and content Westerlund & Frojdh Expires November 9, 2009 [Page 4]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 switching are addressed in Release 7. 3GPP has also specified the Multimedia Broadcast/Multicast Service (MBMS) that uses SDP. The IP layer protocols used by this service are specified in technical specification TS 26.346 Release 6 [MBMS]. Release 7 extends the MBMS User Service to also work with unicast bearers for interactive and streaming traffic classes. In the process of defining these services, there has occasionally been the need to extend both SDP and RTSP functionality. These extensions have mostly been in the form of SDP attributes and RTSP headers and option tags. 3GPP uses the name option tags (like RTSP 2.0 for what RTSP 1.0 calls option tags, option tag is the name that will be used in this document. The purpose of this informational document is to register these SDP and RTSP extensions, in order to avoid future conflicts, and also to raise the awareness of their existence within IETF. This document defines in Section 5.4 three SDP protocol identifiers used in MBMS to enable the usage of block-based FEC. The other SDP and RTSP extensions registered by this document are not normatively defined in this document. Instead the normative definitions are referenced by the registrations. The document begins with two chapters presenting the different extensions of SDP for PSS and MBMS, respectively, followed by a section noting that offer/answer considerations are not applicable here. The subsequent section presents the extensions of RTSP for PSS. The IANA registration of SDP attributes and protocol identifiers is given in Section 8.1, and the RTSP headers and option tags in Section 8.2. For normative descriptions of all SDP and RTSP extensions we refer to TS 26.234 [PSS-234] and TS 26.346 [MBMS]. 3. Applicability Statement This document describes 3GPP-defined extensions to SDP [RFC4566] and RTSP [RFC2326] and registers attributes that are normatively defined in 3GPP technical specifications 26.234, 26.244 and 26.346 up to the referenced versions of the respective documents. The SDP and RTSP extensions have only been defined for usage with the 3GPP service in mind. The applicability for usage outside of these services has not been considered or addressed. Usage of these attributes in other contexts may require further definitions or clarifications. For example, all SDP attributes lack offer/answer usage rules [RFC3264] which currently makes it impossible to use them with offer/answer. Please note that change control of these SDP and Westerlund & Frojdh Expires November 9, 2009 [Page 5]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 RTSP extensions belongs to 3GPP. 4. PSS SDP Extensions The PSS specification [PSS-234] defines a number of different SDP attributes for different purposes. They are informatively listed below grouped by purpose. The text is intentionally not specific enough to allow implementation from this document. The normative definition is in the 3GPP technical specification cited. 4.1. Video Buffering Attributes The following attributes are used to provide parameters for the video buffer model provided in Annex G and Section 5.3.3.2 of [PSS-234]. The attributes were defined in Release 5 as "X-" attributes and were at the time not considered for registration. In hindsight, however, they should not have been "X-" attributes, and they should have been registered, as the registration rules of SDP [RFC4566] point out. Changing their names today is impossible due to the deployed base of millions of mobile handsets supporting PSS, and therefore they are registered in their current form. All attributes are defined at media level. o The "a=X-predecbufsize" attribute provides the size of the pre- decoder buffer in bytes. o The "a=X-initpredecbufperiod" attribute provides the time during which a receiver should initially buffer, in 90kHz ticks, before starting to consume the data in the buffer in order to ensure that underflow does not occur, assuming correct data delivery. o The "a=X-initpostdecbufperiod" attribute provides the initial buffering period, in 90kHz ticks, for the post-decoder buffer present in H.263 and MPEG-4 Visual. o The "a=X-decbyterate" attribute indicates the maximum peak byte- decoding rate used in the verification of the Annex G buffer model expressed in bytes per second. o The "a=3gpp-videopostdecbufsize" attribute is used to indicate the value used in determining the H.264 video post-decoder buffer size. Note that complete descriptions of these attributes can be found in section 5.3.3.2 of [PSS-234]. Westerlund & Frojdh Expires November 9, 2009 [Page 6]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 4.2. Video Frame Size Attribute This media-level attribute provides the receiver with the largest picture size a specific H.263 payload type will carry within the session. The attribute has the following form (see 5.3.3.2 of [PSS-234]): "a=framesize:<payload type number> <width>-<height>" 4.3. Integrity Protection Configuration Attributes These attributes are all used to configure the integrity-protection mechanism defined in Annex K (section K.2.2.1, K.2.2.2 and K.2.2.3) of [PSS-234]. o The session-level attribute "a=3GPP-Integrity-Key" carries the integrity key used to derive SRTP master keys for integrity protection. They key is protected in different ways depending on a method identifier. When using OMA DRM keymanagement, the key is encrypted using AES [AES] before it is base64 encoded [RFC4648]. o The media-level attribute "a=3GPP-SRTP-Config" is used to configure SRTP for integrity protection and contains an integrity nonce, a key salt used in deriving the SRTP master key from the integrity key, and any SRTP configuration parameters, such as the integrity tag length. o The session-level attribute "a=3GPP-SDP-Auth" is used to carry an authentication tag calculated over certain parts of the SDP to prevent manipulation of the security attributes. 4.4. The Alternative Attributes Two media and one session-level attributes are used in a mechanism for providing alternative SDP lines. One or more SDP lines at media level can be replaced, if desired, by alternatives. The mechanism is backwards compatible in the way that a receiver that does not support the attributes will get the default configuration. The different alternatives can be grouped using different attributes that can be specified hierarchically with a top and a lower level. 3GPP Release 6 supports grouping based on bit-rate, according to the SDP bandwidth modifiers AS and TIAS, and language. The SDP attributes (see 5.3.3.3 and 5.3.3.4 of [PSS-234]) are: o The media-level attribute "a=alt:<id>:<SDP-Line>" carries any SDP line and an alternative identifier. Westerlund & Frojdh Expires November 9, 2009 [Page 7]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 o The media-level attribute "a=alt-default-id:<id>" identifies the default configuration to be used in groupings. o The session-level attribute "a=alt-group" is used to group different recommended media alternatives. Providing aggregated properties for the whole group according to the grouping type. Language and bit-rate are two defined grouping types. 4.5. Adaptation Attribute The media-level SDP attribute "a=3GPP-Adaptation-Support" (see 5.3.3.5 of [PSS-234]) is defined as part of the negotiation procedure of the PSS adaptation mechanism. The attribute carries a single value indicating how often the RTCP "Next Application Data Unit" (NADU) APP packet shall be included in sent RTCP compound packets. The adaptation mechanism allows the client to provide the server with information on the available transmission bit-rate and receiver buffer status. 4.6. Quality of Experience Attribute The session and media-level attribute "a=3GPP-QoE-Metrics" (see 5.3.3.6 of [PSS-234]]) is used to negotiate the usage of the quality of experience metrics. The included parameters indicate which metrics, over which duration there should be measurements, and how often reports should be sent. 4.7. Asset Information Attribute The session and media-level attribute "a=3GPP-Asset-Information" (see 5.3.3.7 of [PSS-234]) can exist in multiple instances in a description and describes different types of asset information. The different asset classes defined in Release 6 are: Title, Description, Copyright, Performer, Author, Genre, Rating, Classification, Keywords, Location, Album, and Recording Year. The different assets are described with a BASE64-encoded asset box from the 3GP file format [PSS-3GP]. 5. MBMS SDP Extensions The MBMS specification [MBMS] defines a number of different SDP attributes for different purposes. They are informatively listed below. Westerlund & Frojdh Expires November 9, 2009 [Page 8]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 5.1. MBMS Bearer Mode Declaration Attribute The session and media-level attribute "a=mbms-mode" (see 7.3.2.7 of [MBMS]) is used to describe MBMS broadcast mode media. The attribute may be used at session level to set the default for all media and at media level to specify differences between media. However, the attribute is never used at session level when the session includes MBMS multicast mode media, nor at media level to describe MBMS multicast mode media. 5.2. FEC Flow ID Attribute The media-level attribute "a=mbms-flowid" (see 8.3.1.9 of [MBMS]) maps one or more FEC source block flow IDs to their corresponding destination IP addresses and UDP port numbers. It is present in each SDP media block for repair packet streams. 5.3. MBMS Repair Attribute The session and media-level attribute "a=mbms-repair" (see 8.3.1.8 of [MBMS]) is used to provide FEC repair packets with non-FEC specific parameters. For Release 6 one such parameter is defined, specifying the required minimum receiver buffer time. 5.4. SDP Protocol Identifiers for FEC MBMS defines a mechanism to provide block-based FEC for UDP-based traffic. This solution uses the SDP protocol "proto" identifier to identify the media streams that use the FEC shim layer. The media streams may be either source streams and repair streams. As required by SDP [RFC4566] these protocol identifiers are normatively defined in this document in accordance with their usage specified by 3GPP. 5.4.1. RTP Protocol Identifiers For FEC-protected RTP streams the following two "proto" identifiers are defined: o UDP/MBMS-FEC/RTP/AVP o UDP/MBMS-FEC/RTP/SAVP They indicate the usage of UDP [RFC0768] with MBMS FEC Source packet formats, as defined in Section 8.2.2.4 of [MBMS], that transport RTP packets in accordance with the AVP [RFC3551] or SAVP (Secure RTP) [RFC3711] profiles, respectively. These protocol identifiers SHALL use the FMT space rules that are used for RTP/AVP and RTP/SAVP, respectively. Westerlund & Frojdh Expires November 9, 2009 [Page 9]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 5.4.2. FEC Repair Data Identifier A media stream carrying MBMS FEC repair information over UDP requires its own "proto" identifier. Protocol identifier "UDP/MBMS-REPAIR" identifies the FEC repair packet containing the protocol combination of UDP [RFC0768] and FEC repair payload ID and repair symbols as specified in Section 8.2.2.5 of [MBMS]. The FMT string is not used and SHALL be set to "*". 5.5. Video Buffering Attribute The PSS media-level buffer attribute "a=X-initpredecbufperiod"(See Section 4.1) that specifies an initial buffering time is also used for MBMS in Release 7. It is mainly intended for video streams, but may be used for other media types as well (See Section 8.3.1.1 of [MBMS]). 6. SDP Offer/Answer Consideration The usage of the SDP attributes in an Offer/Answer [RFC3264] context is not defined. These SDP attributes are defined for being used in a declarative context, and for PSS specifically in RTSP [RFC2326] context. 7. PSS RTSP Extensions The RTSP extensions for PSS consist of a number of new RTSP headers and option tags and a narrowing of URI usage in regards to 3GP files. The headers and option tags are informatively described here; see [PSS-234] for the normative declaration. 7.1. 3GPP-Link-Char Header The "3GPP-Link-Char" header (see 5.3.2.1 of [PSS-234]) is used by clients to provide the server with QoS information about the wireless link it is currently using. The header can be used to provide the server with three different QoS parameters: o Guaranteed Bandwidth o Maximum Bandwidth o Maximum Transfer Delay The header may be included in RTSP requests using either of the methods SETUP, PLAY, OPTIONS and SET_PARAMETER. Westerlund & Frojdh Expires November 9, 2009 [Page 10]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 7.2. 3GPP-Adaptation Header The "3GPP-Adaptation" header (see 5.3.2.2 of [PSS-234]) is used by the client to provide the server with adaptation-related parameters and to indicate support of the adaptation function. The header carries the resource identification as a URI, the client's buffer size, and the desired target time. The header may be included in requests using the methods SETUP, PLAY, OPTIONS and SET_PARAMETER. The response to a request using this method shall include this header. 7.3. 3GPP-QoE-Metrics Header The "3GPP-QoE-Metrics" header (see 5.3.2.3.1 of [PSS-234]) is used to negotiate the usage of the quality of experience (QoE) metrics (see Section 11 of [PSS-234]). The header may be included in requests and responses using the SETUP, SET_PARAMTER, OPTIONS or PLAY method. 7.4. 3GPP-QoE-Feedback Header The "3GPP-QoE-Feedback" header (see 5.3.2.3.2 of [PSS-234]) is used to carry QoE metrics from the client to the server when it reports, which happen either during or at the end of the media delivery. The header may be included in requests using the SET_PARAMETER, PAUSE, or TEARDOWN method. 7.5. Video Buffer Headers PSS uses several headers to provide the client with the different buffer parameters. They provide the buffer status at the point of a stream that a PLAY request plays from. These headers may only be used in PLAY responses. See Section 5.3.2.4 and Annex G of [PSS-234] for normative definitions. The three "x-" headers were defined in 3GPP Release 5. When it was realized that they should not have been given "x-" names it was too late rename them due to deployment. The RTSP headers are: o x-predecbufsize o x-initpredecbufperiod Westerlund & Frojdh Expires November 9, 2009 [Page 11]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 o x-initpostdecbufperiod o 3gpp-videopostdecbufsize 7.6. Integrity Protection The integrity-protection mechanism defined in PSS Annex K uses the "3GPP-Freshness-Token" (See Section K.2.2.4 of [PSS-234]) RTSP header to carry a freshness token in DESCRIBE requests. 7.7. RTSP URI Extension The PSS specification also defines syntax for referencing tracks within the "3GP" file format [PSS-3GP]. The 3GP format is based on the ISO base media file format and defined in several different profiles, including a streaming-server profile, in Release 6. This syntax is fully contained within the generic URI syntax defined for RTSP URIs. It is only a syntax restriction server manufacturers follow to allow clients or proxies to understand what encodes the track number in the URI. This is provided for information only. To identify a track within a 3GP file the last URI segment has to contain a structure that is <alpha string>=<track nr> (See 5.3.3.1 of [PSS-234]). 7.8. Fast Start-up and Content Switching Release 7 of PSS defines a number of extensions in terms of headers and option tags (See Section 5.5 of [PSS-234]) for support of fast start-up and switching of content for on-demand and live applications built on top of PSS. Clients are enabled to reuse the existing RTSP control session and RTP resources while switching to new content. The RTSP headers are: o Switch-Stream o SDP-Requested o Pipelined-Requests The RTSP option tags are: o 3gpp-pipelined o 3gpp-switch Westerlund & Frojdh Expires November 9, 2009 [Page 12]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 o 3gpp-switch-req-sdp o 3gpp-switch-stream 8. IANA Considerations 8.1. SDP Registrations IANA is requested to register the SDP attributes listed below in the registry at http://www.iana.org/assignments/sdp-parameters. The contact person for this registration is Magnus Westerlund (magnus.westerlund@ericsson.com) Phone number +46 8 719 0000. Westerlund & Frojdh Expires November 9, 2009 [Page 13]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 SDP Protocol Identifiers ("proto"): Name: UDP/MBMS-FEC/RTP/AVP Long form: 3GPP MBMS FEC protected RTP/AVP over UDP Type of name: proto Purpose: 3GPP MBMS defines a mechanism to provide block- based FEC for UDP-based traffic. This solution uses the SDP protocol "proto" identifier to identify the media streams that use the FEC shim layer. This protocol identifier indicates that the FEC protected data is RTP using the AVP profile. Reference: RFCXXXX, 3GPP TS 26.346 Name: UDP/MBMS-FEC/RTP/SAVP Long form: 3GPP MBMS FEC protected RTP/SAVP over UDP Type of name: proto Purpose: 3GPP MBMS defines a mechanism to provide block- based FEC for UDP-based traffic. This solution uses the SDP protocol "proto" identifier to identify the media streams that use the FEC shim layer. This protocol identifier indicates that the FEC protected data is RTP using the Secure AVP profile (SAVP). Reference: RFCXXXX, 3GPP TS 26.346 Name: UDP/MBMS-REPAIR Long form: 3GPP MBMS FEC repair symbols over UDP Type of name: proto Purpose: 3GPP MBMS defines a mechanism to provide block- based FEC for UDP-based traffic. This solution uses the SDP protocol "proto" identifier to identify the media streams that use the FEC shim layer. This protocol identifier indicates that the FEC repair data is sent over UDP. Reference: RFCXXXX, 3GPP TS 26.346 SDP Attribute ("att-field"): Attribute name: X-predecbufsize Long form: Pre-decoder buffer size Type of name: att-field Type of attribute: Media level only Subject to charset: No Purpose: See Section 4.1 Reference: 3GPP TS 26.234, Section 5.3.3.2 Values: See Reference Westerlund & Frojdh Expires November 9, 2009 [Page 14]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 Attribute name: X-initpredecbufperiod Long form: Pre-decoder initial buffering period Type of name: att-field Type of attribute: Media level only Subject to charset: No Purpose: See Section 4.1 Reference: 3GPP TS 26.234, Section 5.3.3.2 Values: See Reference Attribute name: X-initpostdecbufperiod Long form: Post-decoder initial buffering period Type of name: att-field Type of attribute: Media level only Subject to charset: No Purpose: See Section 4.1 Reference: 3GPP TS 26.234, Section 5.3.3.2 Values: See Reference Attribute name: X-decbyterate Long form: Peak decoding rate in bytes per second Type of name: att-field Type of attribute: Media level only Subject to charset: No Purpose: See Section 4.1 Reference: 3GPP TS 26.234, Section 5.3.3.2 Values: See Reference Attribute name: 3gpp-videopostdecbufsize Long form: Post decoder buffer size Type of name: att-field Type of attribute: Media level only Subject to charset: No Purpose: See Section 4.1 Reference: 3GPP TS 26.234, Section 5.3.3.2 Values: See Reference Attribute name: framesize Long form: Maximum Video Frame Size Type of name: att-field Type of attribute: Media level only Subject to charset: No Purpose: See Section 4.2 Reference: 3GPP TS 26.234, Section 5.3.3.2 Values: See Reference Attribute name: 3GPP-Integrity-Key Long form: 3GPP DRM Integrity Key Type of name: att-field Westerlund & Frojdh Expires November 9, 2009 [Page 15]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 Type of attribute: Session level only Subject to charset: No Purpose: See Section 4.3 Reference: 3GPP TS 26.234, Sections 5.3.3.2 and K.2.2.1 Values: See Reference Attribute name: 3GPP-SRTP-Config Long form: 3GPP DRM SRTP Configuration Type of name: att-field Type of attribute: Media level only Subject to charset: No Purpose: See Section 4.3 Reference: 3GPP TS 26.234, Sections 5.3.3.2 and K.2.2.2 Values: See Reference Attribute name: 3GPP-SDP-Auth Long form: 3GPP DRM Integrity SDP Authentication Type of name: att-field Type of attribute: Session level only Subject to charset: No Purpose: See Section 4.3 Reference: 3GPP TS 26.234, Sections 5.3.3.2 and K.2.2.3 Values: See Reference Attribute name: alt Long form: Alternative SDP line Type of name: att-field Type of attribute: Media level only Subject to charset: No Purpose: See Section 4.4 Reference: 3GPP TS 26.234, Section 5.3.3.3 Values: See Reference Attribute name: alt-default-id Long form: Default alternative ID Type of name: att-field Type of attribute: Media level only Subject to charset: No Purpose: See Section 4.4 Reference: 3GPP TS 26.234, Section 5.3.3.3 Values: See Reference Attribute name: alt-group Long form: Grouping of SDP Line alternatives Type of name: att-field Type of attribute: Session level only Subject to charset: No Purpose: See Section 4.4 Westerlund & Frojdh Expires November 9, 2009 [Page 16]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 Reference: 3GPP TS 26.234, Section 5.3.3.4 Values: See Reference Attribute name: 3GPP-Adaptation-Support Long form: 3GPP Adaptation Support Type of name: att-field Type of attribute: Media level only Subject to charset: No Purpose: See Section 4.5 Reference: 3GPP TS 26.234, Section 5.3.3.5 Values: See Reference Attribute name: 3GPP-QoE-Metrics Long form: 3GPP Quality of Experience Metrics Type of name: att-field Type of attribute: Session and Media level Subject to charset: No Purpose: See Section 4.6 Reference: 3GPP TS 26.234, Section 5.3.3.6 Values: See Reference Attribute name: 3GPP-Asset-Information Long form: 3GPP Asset Information Type of name: att-field Type of attribute: Session and Media level Subject to charset: No Purpose: See Section 4.7 Reference: 3GPP TS 26.234, Section 5.3.3.7 Values: See Reference Attribute name: mbms-mode Long form: MBMS Bearer Mode Declaration Type of name: att-field Type of attribute: Session and Media level Subject to charset: No Purpose: See Section 5.1 Reference: 3GPP TS 26.346, Section 7.3.2.7 Values: See Reference Attribute name: mbms-flowid Long form: FEC Flow ID Type of name: att-field Type of attribute: Media level Subject to charset: No Purpose: See Section 5.2 Reference: 3GPP TS 26.346, Section 8.3.1.9 Values: See Reference Westerlund & Frojdh Expires November 9, 2009 [Page 17]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 Attribute name: mbms-repair Long form: MBMS Repair Type of name: att-field Type of attribute: Session and Media level Subject to charset: No Purpose: See Section 5.3 Reference: 3GPP TS 26.346, Section 8.3.1.8 Values: See Reference 8.2. RTSP Registrations IANA is requested to register the RTSP headers listed below in the RTSP 1.0 registry table "RTSP/1.0 Headers" at: http://www.iana.org/assignments/rtsp-parameters. Note: This registry requires Standards document, preferably an IETF RFC. The document that defines the registered headers below is a technical standards document from 3GPP, although the request for registration is submitted using this document to achieve further information spreading within IETF. The contact person for this registration is Magnus Westerlund (magnus.westerlund@ericsson.com) Phone number +46 8 719 0000. Header Name: 3GPP-Freshness-Token Purpose: See Section K.2 of 3GPP TS 26.234 Methods: DESCRIBE Requests Reference: Section K.2.2.4 of 3GPP TS 26.234 Values: See Reference Header Name: 3GPP-Link-Char Purpose: See Section 5.3.2.1 of 3GPP TS 26.234 Methods: SETUP, PLAY, OPTIONS or SET_PARAMETER Requests Reference: Section 5.3.2.1 of 3GPP TS 26.234 Values: See Reference Header Name: 3GPP-Adaptation Purpose: See Section 5.3.2.2 of 3GPP TS 26.234 Methods: SETUP, PLAY, OPTIONS, or SET_PARAMETER Requests and Responses Reference: Section 5.3.2.2 of 3GPP TS 26.234 Values: See Reference Header Name: 3GPP-QoE-Metrics Purpose: See Section 5.3.2.3.1 of 3GPP TS 26.234 Methods: SETUP, PLAY, OPTIONS, or SET_PARAMETER Requests Westerlund & Frojdh Expires November 9, 2009 [Page 18]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 and Responses Reference: Section 5.3.2.3.1 of 3GPP TS 26.234 Values: See Reference Header Name: 3GPP-QoE-Feedback Purpose: See Section 5.3.2.3.2 of 3GPP TS 26.234 Methods: SET_PARAMETER, PAUSE, or TEARDOWN Requests Reference: Section 5.3.2.3.2 of 3GPP TS 26.234 Values: See Reference Header Name: Switch-Stream Purpose: See Section 5.5.4.2 of 3GPP TS 26.234 Methods: PLAY Requests and Responses Reference: Section 5.5.4.2 of 3GPP TS 26.234 Values: See Reference Header Name: SDP-Requested Purpose: See Section 5.5.4.4 of 3GPP TS 26.234 Methods: PLAY Requests Reference: Section 5.5.4.4 of 3GPP TS 26.234 Values: See Reference Header Name: Pipelined-Requests Purpose: See Section 5.5.3 of 3GPP TS 26.234 Methods: SETUP and PLAY Requests Reference: Section 5.5.3 of 3GPP TS 26.234 Values: See Reference Header Name: x-predecbufsize Purpose: See Section 5.3.2.4 of 3GPP TS 26.234 Methods: PLAY Response Reference: Section 5.3.2.4 of 3GPP TS 26.234 Values: See Reference Header Name: x-initpredecbufperiod Purpose: See Section 5.3.2.4 of 3GPP TS 26.234 Methods: PLAY Response Reference: Section 5.3.2.4 of 3GPP TS 26.234 Values: See Reference Header Name: x-initpostdecbufperiod Purpose: See Section 5.3.2.4 of 3GPP TS 26.234 Methods: PLAY Response Reference: Section 5.3.2.4 of 3GPP TS 26.234 Values: See Reference Header Name: 3gpp-videopostdecbufsize Purpose: See Section 5.3.2.4 of 3GPP TS 26.234 Westerlund & Frojdh Expires November 9, 2009 [Page 19]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 Methods: PLAY Response Reference: Section 5.3.2.4 of 3GPP TS 26.234 Values: See Reference Header Name: Supported Purpose: See Section 5.5.2.2.2 of 3GPP TS 26.234 Methods: Any Request and Response Reference: Section 5.5.2.2.2 of 3GPP TS 26.234 Values: See Reference IANA is requested to register the RTSP Option tags (option tags) listed below in the RTSP 1.0 registry table for RTSP/1.0 Option Tags http://www.iana.org/assignments/rtsp-parameters. Option tag: 3gpp-pipelined Purpose: See Section 5.5.3 of 3GPP TS 26.234 Applies to: Client and Server Reference: Section 5.5.3 of 3GPP TS 26.234 Values: See Reference Option tag: 3gpp-switch Purpose: See Section 5.5.4.2 of 3GPP TS 26.234 Applies to: Client and Server Reference: Section 5.5.4.2 of 3GPP TS 26.234 Values: See Reference Option tag: 3gpp-switch-req-sdp Purpose: See Section 5.5.4.4 of 3GPP TS 26.234 Applies to: Client and Server Reference: Section 5.5.4.4 of 3GPP TS 26.234 Values: See Reference Option tag: 3gpp-switch-stream Purpose: See Section 5.5.4.5 of 3GPP TS 26.234 Applies to: Client and Server Reference: Section 5.5.4.5 of 3GPP TS 26.234 Values: See Reference 9. Security Considerations SDP attributes are subject to modification by an attacker unless they are integrity protected and authenticated. The security consideration of the SDP specification [RFC4566] should be reviewed in this regard. The registered SDP attributes are vulnerable to Westerlund & Frojdh Expires November 9, 2009 [Page 20]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 modification attacks or removal, which may result in problems of serious nature, including failure to use service and reduced quality. The registered RTSP headers are also vunerable to insertion, deletion or modification attacks similar to SDP attributes. Also in this case it can result in failure of the service or reduced quality of streaming content. The three SDP protocol identifiers do not by themselves introduce any additional security threats that don't exist for other protocol identifiers in SDP. The media stream and the protocols identified by the protocol identifier may however contain security issues by themselves. 10. Acknowledgements 11. References 11.1. Normative References [MBMS] 3GPP TS 26.346 version 7.10.0 (2009-03), "Multimedia Broadcast/Multicast Service (MBMS); Protocols and codecs". [PSS-234] 3GPP TS 26.234 version 7.7.0 (2009-03), "Transparent end- to-end Packet-switched Streaming Service (PSS); Protocols and codecs,". [PSS-3GP] 3GPP TS 26.244 version 7.3.0 (2007-12), "Transparent end- to-end packet switched streaming service (PSS); 3GPP file format (3GP)". [RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768, August 1980. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3551] Schulzrinne, H. and S. Casner, "RTP Profile for Audio and Video Conferences with Minimal Control", STD 65, RFC 3551, July 2003. [RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, "The Secure Real-time Transport Protocol (SRTP)", RFC 3711, March 2004. Westerlund & Frojdh Expires November 9, 2009 [Page 21]
Internet-Draft SDP & RTSP extensions for 3GPP May 2009 11.2. Informative References [AES] ""Advanced Encryption Standard (AES)", FIPS PUB 197, http://www.nist.gov/aes/.". [PSS-233] 3GPP TS 26.233 version 7.0.0 (2007-06), "Transparent end- to-end packet switched streaming service (PSS) General Description". [RFC2326] Schulzrinne, H., Rao, A., and R. Lanphier, "Real Time Streaming Protocol (RTSP)", RFC 2326, April 1998. [RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model with Session Description Protocol (SDP)", RFC 3264, June 2002. [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session Description Protocol", RFC 4566, July 2006. [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data Encodings", RFC 4648, October 2006. 11.3. Authors' Addresses Magnus Westerlund Ericsson Farogatan 6 Stockholm, SE-164 80 SWEDEN Phone: +46 8 7190000 Fax: +46 8 757 55 50 Email: magnus.westerlund@ericsson.com Per Frojdh Ericsson Farogatan 6 Stockholm, SE-164 80 SWEDEN Phone: +46 8 7190000 Fax: +46 8 757 55 50 Email: per.frojdh@ericsson.com Westerlund & Frojdh Expires November 9, 2009 [Page 22]
