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Checking references for intended status: Informational ---------------------------------------------------------------------------- -- Obsolete informational reference (is this intentional?): RFC 2326 (Obsoleted by RFC 7826) -- Obsolete informational reference (is this intentional?): RFC 4566 (Obsoleted by RFC 8866) Summary: 0 errors (**), 0 flaws (~~), 2 warnings (==), 4 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group M. Westerlund 3 Internet-Draft P. Frojdh 4 Intended status: Informational Ericsson 5 Expires: March 21, 2011 Sep 17, 2010 7 SDP and RTSP extensions defined for 3GPP Packet-switched Streaming 8 Service and Multimedia Broadcast/Multicast Service 9 draft-westerlund-mmusic-3gpp-sdp-rtsp-08 11 Abstract 13 The Packet-switched Streaming Service (PSS) and the Multimedia 14 Broadcast/Multicast Service (MBMS) defined by 3GPP use SDP and RTSP 15 with some extensions. This document provides information about these 16 extensions and registers the RTSP and SDP extensions with IANA. 18 Requirements Language 20 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 21 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 22 document are to be interpreted as described in RFC 2119 [RFC2119]. 24 Status of this Memo 26 This Internet-Draft is submitted in full conformance with the 27 provisions of BCP 78 and BCP 79. 29 Internet-Drafts are working documents of the Internet Engineering 30 Task Force (IETF). Note that other groups may also distribute 31 working documents as Internet-Drafts. The list of current Internet- 32 Drafts is at http://datatracker.ietf.org/drafts/current/. 34 Internet-Drafts are draft documents valid for a maximum of six months 35 and may be updated, replaced, or obsoleted by other documents at any 36 time. It is inappropriate to use Internet-Drafts as reference 37 material or to cite them other than as "work in progress." 39 This Internet-Draft will expire on March 21, 2011. 41 Copyright Notice 43 Copyright (c) 2010 IETF Trust and the persons identified as the 44 document authors. All rights reserved. 46 This document is subject to BCP 78 and the IETF Trust's Legal 47 Provisions Relating to IETF Documents 48 (http://trustee.ietf.org/license-info) in effect on the date of 49 publication of this document. Please review these documents 50 carefully, as they describe your rights and restrictions with respect 51 to this document. Code Components extracted from this document must 52 include Simplified BSD License text as described in Section 4.e of 53 the Trust Legal Provisions and are provided without warranty as 54 described in the Simplified BSD License. 56 Table of Contents 58 1. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 4 59 1.1. Glossary . . . . . . . . . . . . . . . . . . . . . . . . . 4 60 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 61 3. Applicability Statement . . . . . . . . . . . . . . . . . . . 5 62 4. PSS SDP Extensions . . . . . . . . . . . . . . . . . . . . . . 6 63 4.1. Video Buffering Attributes . . . . . . . . . . . . . . . . 6 64 4.2. Video Frame Size Attribute . . . . . . . . . . . . . . . . 7 65 4.3. Integrity Protection Configuration Attributes . . . . . . 7 66 4.4. The Alternative Attributes . . . . . . . . . . . . . . . . 7 67 4.5. Adaptation Attribute . . . . . . . . . . . . . . . . . . . 8 68 4.6. Quality of Experience Attribute . . . . . . . . . . . . . 8 69 4.7. Asset Information Attribute . . . . . . . . . . . . . . . 8 70 5. MBMS SDP Extensions . . . . . . . . . . . . . . . . . . . . . 9 71 5.1. MBMS Bearer Mode Declaration Attribute . . . . . . . . . . 9 72 5.2. FEC Flow ID Attribute . . . . . . . . . . . . . . . . . . 9 73 5.3. MBMS Repair Attribute . . . . . . . . . . . . . . . . . . 9 74 5.4. SDP Protocol Identifiers for FEC . . . . . . . . . . . . . 9 75 5.4.1. RTP Protocol Identifiers . . . . . . . . . . . . . . . 9 76 5.4.2. FEC Repair Data Identifier . . . . . . . . . . . . . . 10 77 5.5. Video Buffering Attribute . . . . . . . . . . . . . . . . 10 78 6. SDP Offer/Answer Consideration . . . . . . . . . . . . . . . . 10 79 7. PSS RTSP Extensions . . . . . . . . . . . . . . . . . . . . . 10 80 7.1. 3GPP-Link-Char Header . . . . . . . . . . . . . . . . . . 10 81 7.2. 3GPP-Adaptation Header . . . . . . . . . . . . . . . . . . 11 82 7.3. 3GPP-QoE-Metrics Header . . . . . . . . . . . . . . . . . 11 83 7.4. 3GPP-QoE-Feedback Header . . . . . . . . . . . . . . . . . 11 84 7.5. Video Buffer Headers . . . . . . . . . . . . . . . . . . . 11 85 7.6. Integrity Protection . . . . . . . . . . . . . . . . . . . 12 86 7.7. RTSP URI Extension . . . . . . . . . . . . . . . . . . . . 12 87 7.8. Fast Start-up and Content Switching . . . . . . . . . . . 12 88 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 89 8.1. SDP Registrations . . . . . . . . . . . . . . . . . . . . 13 90 8.2. RTSP Registrations . . . . . . . . . . . . . . . . . . . . 18 91 9. Security Considerations . . . . . . . . . . . . . . . . . . . 20 92 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 21 93 10.1. Normative References . . . . . . . . . . . . . . . . . . . 21 94 10.2. Informative References . . . . . . . . . . . . . . . . . . 21 95 10.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 97 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 22 99 1. Definitions 101 1.1. Glossary 103 3GP: 3GPP file format, a multi-media file format based on the ISO 104 base media file format, existing in different profiles intended 105 for multimedia messages, direct playback on clients, progressive 106 download, usage on servers to deliver on-demand multi-media 107 sessions in PSS, or servers sending MBMS sessions. 109 3GPP: Third Generation Partnership Project, see www.3gpp.org for 110 more information about this organization. 112 FEC: Forward Error Correction 114 MBMS: Multimedia Broadcast/Multicast Service, a service defined by 115 3GPP that utilizes broadcast or multicast technologhy in 116 combination with unicast for delivery of a wide range of content 117 to mobile terminals. 119 PSS: Packet-switched Streaming Service, a unicast-based streaming 120 service for delivery of on-demand or live streaming multi-media 121 content to mobile terminals. 123 RTSP: Real Time Streaming Protocol, see [RFC2326]. 125 SDP: Session Description Protocol, see [RFC4566]. 127 SRTP: Secure Real-time Transport Protocol, see [RFC3711]. 129 QoE: Quality of Experience, the quality level of the the user 130 experience of a service. In PSS, this is estimated by a 131 combination of application-level metrics. 133 QoS: Quality of Service, the quality (properties) that the network 134 provides toward the upper layer service. 136 2. Introduction 138 3GPP has specified the Packet-switched Streaming Service (PSS) that 139 uses both RTSP [RFC2326] and SDP [RFC4566]. The service is specified 140 in technical specifications TS 26.233 [PSS-233] and TS 26.234 141 [PSS-234] in Release 4 and subsequent releases. The basic service 142 defined in Release 4 is enhanced in Release 5 with capability 143 exchange and in Release 6 with a number of features, such as 144 adaptation, digital rights management, progressive download as well 145 as a streaming server file-format defined in [PSS-3GP]. Fast 146 start-up and content switching are addressed in Release 7. 148 3GPP has also specified the Multimedia Broadcast/Multicast Service 149 (MBMS) that uses SDP. The IP layer protocols used by this service 150 are specified in technical specification TS 26.346 Release 6 [MBMS]. 151 Release 7 extends the MBMS User Service to also work with unicast 152 bearers for interactive and streaming traffic classes. 154 In the process of defining these services, there has occasionally 155 been a need to extend both SDP and RTSP functionalities. These 156 extensions have mostly been in the form of SDP attributes and RTSP 157 headers and option tags. 3GPP uses the name feature tags (like RTSP 158 2.0 for what RTSP 1.0 calls option tags), option tag is the name that 159 will be used in this document. The purpose of this informational 160 document is to register these SDP and RTSP extensions, in order to 161 avoid future conflicts, and also to raise the awareness of their 162 existence within IETF. 164 This document defines in Section 5.4 three SDP protocol identifiers 165 used in MBMS to enable the usage of block-based FEC. The SDP 166 protocol identifiers require an IETF RFC to be defined and 167 registered. Thus any semantic change will require a new IETF 168 approved RFC. The other SDP and RTSP extensions registered by this 169 document are not normatively defined in this document. Instead the 170 normative definitions are referenced by the registrations. 3GPP can 171 update the normative definition in future version of their 172 specifications. However to ensure that such a change is visible in 173 IETF at minimal IANA should be notified and the reference to the 3GPP 174 specification updated and preferably an updated version of this RFC 175 published. 177 The document begins with two chapters presenting the SDP extensions 178 for PSS and MBMS, respectively. Followed by a section noting that 179 offer/answer considerations are not applicable here. The subsequent 180 section presents the extensions of RTSP for PSS. The IANA 181 registration of SDP attributes and protocol identifiers is given in 182 Section 8.1, and the RTSP headers and option tags in Section 8.2. 183 For normative descriptions of all SDP and RTSP extensions we refer to 184 TS 26.234 [PSS-234] and TS 26.346 [MBMS]. 186 3. Applicability Statement 188 This document describes 3GPP-defined extensions to SDP [RFC4566] and 189 RTSP [RFC2326] and registers attributes that are normatively defined 190 in 3GPP technical specifications 26.234, 26.244 and 26.346 up to the 191 referenced versions of the respective documents. 193 The SDP and RTSP extensions have only been defined for usage with the 194 3GPP service in mind. The applicability for usage outside of these 195 services has not been considered nor addressed. Usage of these 196 attributes in other contexts may require further definitions or 197 clarifications. For example, all SDP attributes lack offer/answer 198 usage rules [RFC3264] which currently makes it impossible to use them 199 with offer/answer. Please note that change control of these SDP and 200 RTSP extensions belongs to 3GPP. 202 4. PSS SDP Extensions 204 The PSS specification [PSS-234] defines a number of different SDP 205 attributes for different purposes. They are listed below grouped by 206 their purpose. The text is intentionally not specific enough to 207 allow implementation from this document. The normative definition is 208 in the 3GPP technical specification cited. 210 4.1. Video Buffering Attributes 212 The following attributes are used to provide parameters for the video 213 buffer model provided in Annex G and Section 5.3.3.2 of [PSS-234]. 214 The attributes were defined in Release 5 as "X-" attributes and were 215 at the time not considered for registration. In hindsight, however, 216 they should not have been "X-" attributes, and they should have been 217 registered, as the registration rules of SDP [RFC4566] point out. 218 Changing their names today is impossible due to the deployed base of 219 millions of mobile handsets supporting PSS, and therefore they are 220 registered in their current form. 222 All attributes are defined at media level. 224 o The "a=X-predecbufsize" attribute provides the size of the pre- 225 decoder buffer in bytes. 227 o The "a=X-initpredecbufperiod" attribute provides the time during 228 which a receiver should initially buffer, in 90kHz ticks, before 229 starting to consume the data in the buffer in order to ensure that 230 underflow does not occur, assuming correct data delivery. 232 o The "a=X-initpostdecbufperiod" attribute provides the initial 233 buffering period, in 90kHz ticks, for the post-decoder buffer 234 present in H.263 and MPEG-4 Visual. 236 o The "a=X-decbyterate" attribute indicates the maximum peak byte- 237 decoding rate used in the verification of the Annex G buffer model 238 expressed in bytes per second. 240 o The "a=3gpp-videopostdecbufsize" attribute is used to indicate the 241 value used in determining the H.264 video post-decoder buffer 242 size. 244 Note that complete descriptions of these attributes can be found in 245 section 5.3.3.2 of [PSS-234]. 247 4.2. Video Frame Size Attribute 249 This media-level attribute provides the receiver with the largest 250 picture size a specific H.263 payload type will carry within the 251 session. The attribute has the following form (see 5.3.3.2 of 252 [PSS-234]): 254 "a=framesize: -" 256 4.3. Integrity Protection Configuration Attributes 258 These attributes are all used to configure the integrity-protection 259 mechanism defined in Annex K (section K.2.2.1, K.2.2.2 and K.2.2.3) 260 of [PSS-234]. 262 o The session-level attribute "a=3GPP-Integrity-Key" carries the 263 integrity key used to derive SRTP master keys for integrity 264 protection. The key is protected in different ways depending on a 265 method identifier. When using OMA DRM key management, the key is 266 encrypted using AES [AES] before it is base64 encoded [RFC4648]. 268 o The media-level attribute "a=3GPP-SRTP-Config" is used to 269 configure SRTP for integrity protection and contains an integrity 270 nonce, a key salt used in deriving the SRTP master key from the 271 integrity key, and any SRTP configuration parameters, such as the 272 integrity tag length. 274 o The session-level attribute "a=3GPP-SDP-Auth" is used to carry an 275 authentication tag calculated over certain parts of the SDP to 276 prevent manipulation of the security attributes. 278 4.4. The Alternative Attributes 280 Two media and one session-level attributes are used in a mechanism 281 for providing alternative SDP lines. One or more SDP lines at media 282 level can be replaced, if desired, by alternatives. The mechanism is 283 backwards compatible in the way that a receiver that does not support 284 the attributes will get the default configuration. The different 285 alternatives can be grouped using different attributes that can be 286 specified hierarchically with a top and a lower level. 3GPP Release 6 287 supports grouping based on bit-rate, according to the SDP bandwidth 288 modifiers AS and TIAS, and language. 290 The SDP attributes (see 5.3.3.3 and 5.3.3.4 of [PSS-234]) are: 292 o The media-level attribute "a=alt::" carries any SDP 293 line and an alternative identifier. 295 o The media-level attribute "a=alt-default-id:" identifies the 296 default configuration to be used in groupings. 298 o The session-level attribute "a=alt-group" is used to group 299 different recommended media alternatives. Providing aggregated 300 properties for the whole group according to the grouping type. 301 Language and bit-rate are two defined grouping types. 303 4.5. Adaptation Attribute 305 The media-level SDP attribute "a=3GPP-Adaptation-Support" (see 306 5.3.3.5 in [PSS-234]) is defined as part of the negotiation procedure 307 of the PSS adaptation mechanism. The attribute carries a single 308 value indicating how often the RTCP "Next Application Data Unit" 309 (NADU) APP packet shall be included in sent RTCP compound packets. 310 The adaptation mechanism allows the client to provide the server with 311 information on the available transmission bit-rate and receiver 312 buffer status. 314 4.6. Quality of Experience Attribute 316 The session and media-level attribute "a=3GPP-QoE-Metrics" (see 317 5.3.3.6 of [PSS-234]]) is used to negotiate the usage of the quality 318 of experience metrics. The included parameters indicate which 319 metrics, over which duration there should be measurements, and how 320 often reports should be sent. 322 4.7. Asset Information Attribute 324 The session and media-level attribute "a=3GPP-Asset-Information" (see 325 5.3.3.7 of [PSS-234]) can exist in multiple instances in a 326 description and describes different types of asset information. The 327 different asset classes defined in Release 6 are: Title, Description, 328 Copyright, Performer, Author, Genre, Rating, Classification, 329 Keywords, Location, Album, and Recording Year. The different assets 330 are described with a BASE64-encoded asset box from the 3GP file 331 format [PSS-3GP]. 333 5. MBMS SDP Extensions 335 The MBMS specification [MBMS] defines a number of different SDP 336 attributes for different purposes. They are informatively listed 337 below. 339 5.1. MBMS Bearer Mode Declaration Attribute 341 The session and media-level attribute "a=mbms-mode" (see 7.3.2.7 of 342 [MBMS]) is used to describe MBMS broadcast mode media. The attribute 343 may be used at session level to set the default for all media and at 344 media level to specify differences between media. However, the 345 attribute is never used at session level when the session includes 346 MBMS multicast mode media, nor at media level to describe MBMS 347 multicast mode media. 349 5.2. FEC Flow ID Attribute 351 The media-level attribute "a=mbms-flowid" (see 8.3.1.9 of [MBMS]) 352 maps one or more FEC source block flow IDs to their corresponding 353 destination IP addresses and UDP port numbers. It is present in each 354 SDP media block for repair packet streams. 356 5.3. MBMS Repair Attribute 358 The session and media-level attribute "a=mbms-repair" (see 8.3.1.8 of 359 [MBMS]) is used to provide FEC repair packets with non-FEC specific 360 parameters. FFor release 6, one such parameter is defined to specify 361 the required minimum receiver buffer time. 363 5.4. SDP Protocol Identifiers for FEC 365 MBMS defines a mechanism to provide block-based FEC for UDP-based 366 traffic. This solution uses the SDP protocol "proto" identifier to 367 identify the media streams that use the FEC shim layer. The media 368 streams may be either source streams or repair streams. As required 369 by SDP [RFC4566], these protocol identifiers are normatively defined 370 in this document in accordance with their usage specified by 3GPP. 372 5.4.1. RTP Protocol Identifiers 374 For FEC-protected RTP streams, the following two "proto" identifiers 375 are defined: 377 o UDP/MBMS-FEC/RTP/AVP 379 o UDP/MBMS-FEC/RTP/SAVP 380 They indicate the usage of UDP [RFC0768] with MBMS FEC Source packet 381 formats, as defined in Section 8.2.2.4 of [MBMS], that transport RTP 382 packets in accordance with the AVP [RFC3551] or SAVP (Secure RTP) 383 [RFC3711] profiles, respectively. These protocol identifiers SHALL 384 use the FMT space rules that are used for RTP/AVP and RTP/SAVP, 385 respectively. 387 5.4.2. FEC Repair Data Identifier 389 A media stream carrying MBMS FEC repair information over UDP requires 390 its own "proto" identifier. Protocol identifier "UDP/MBMS-REPAIR" 391 identifies the FEC repair packet containing the protocol combination 392 of UDP [RFC0768] and FEC repair payload ID and repair symbols as 393 specified in Section 8.2.2.5 of [MBMS]. The FMT string is not used 394 and SHALL be set to "*". 396 5.5. Video Buffering Attribute 398 The PSS media-level buffer attribute "a=X-initpredecbufperiod"(See 399 Section 4.1) that specifies an initial buffering time is also used 400 for MBMS in Release 7. It is mainly intended for video streams, but 401 may be used for other media types as well (See Section 8.3.1.1 of 402 [MBMS]). 404 6. SDP Offer/Answer Consideration 406 The usage of the SDP attributes in an Offer/Answer [RFC3264] context 407 is not defined. These SDP attributes are defined for being used in a 408 declarative context, and for PSS specifically in RTSP [RFC2326] 409 context. 411 7. PSS RTSP Extensions 413 The RTSP extensions for PSS consist of a number of new RTSP headers 414 and option tags and a narrowing of URI usage in regards to 3GP files. 415 The headers and option tags are informatively described here; see 416 [PSS-234] for the normative declaration. 418 7.1. 3GPP-Link-Char Header 420 The "3GPP-Link-Char" header (see 5.3.2.1 of [PSS-234]) is used by 421 clients to provide the server with QoS information about the wireless 422 link it is currently using. The header can be used to provide the 423 server with three different QoS parameters: 425 o Guaranteed Bandwidth 427 o Maximum Bandwidth 429 o Maximum Transfer Delay 431 The header may be included in RTSP requests using either of the 432 methods SETUP, PLAY, OPTIONS and SET_PARAMETER. 434 7.2. 3GPP-Adaptation Header 436 The "3GPP-Adaptation" header (see 5.3.2.2 of [PSS-234]) is used by 437 the client to provide the server with adaptation-related parameters 438 and to indicate support of the adaptation function. The header 439 carries the resource identification as a URI, the client's buffer 440 size, and the desired target time. 442 The header may be included in requests using the methods SETUP, PLAY, 443 OPTIONS and SET_PARAMETER. The response to a request using this 444 method shall include this header. 446 7.3. 3GPP-QoE-Metrics Header 448 The "3GPP-QoE-Metrics" header (see 5.3.2.3.1 of [PSS-234]) is used to 449 negotiate the usage of the quality of experience (QoE) metrics (see 450 Section 11 of [PSS-234]). 452 The header may be included in requests and responses using the SETUP, 453 SET_PARAMTER, OPTIONS or PLAY method. 455 7.4. 3GPP-QoE-Feedback Header 457 The "3GPP-QoE-Feedback" header (see 5.3.2.3.2 of [PSS-234]) is used 458 to carry QoE metrics from the client to the server when it reports, 459 which happens either during or at the end of the media delivery. 461 The header may be included in requests using the SET_PARAMETER, 462 PAUSE, or TEARDOWN method. 464 7.5. Video Buffer Headers 466 PSS uses several headers to provide the client with the different 467 buffer parameters. They provide the buffer status at the point of a 468 stream that a PLAY request plays from. These headers may only be 469 used in PLAY responses. See Section 5.3.2.4 and Annex G of [PSS-234] 470 for normative definitions. 472 The three "x-" headers were defined in 3GPP Release 5. When it was 473 realized that they should not have been given "x-" names, it was to 474 late rename them due to deployment. 476 The RTSP headers are: 478 o x-predecbufsize 480 o x-initpredecbufperiod 482 o x-initpostdecbufperiod 484 o 3gpp-videopostdecbufsize 486 7.6. Integrity Protection 488 The integrity-protection mechanism defined in PSS Annex K uses the 489 "3GPP-Freshness-Token" (See Section K.2.2.4 of [PSS-234]) RTSP header 490 to carry a freshness token in DESCRIBE requests. 492 7.7. RTSP URI Extension 494 The PSS specification also defines syntax for referencing tracks 495 within the "3GP" file format [PSS-3GP]. The 3GP format is based on 496 the ISO base media file format and defined in several different 497 profiles, including a streaming-server profile, in Release 6. 499 This syntax is fully contained within the generic URI syntax defined 500 for RTSP URIs. It is only a syntax restriction that server 501 manufacturers follow to allow clients or proxies to understand what 502 encodes the track number in the URI. This is provided for 503 information only. 505 To identify a track within a 3GP file the last URI segment has to 506 contain a structure that is = (See 5.3.3.1 of 507 [PSS-234]). 509 7.8. Fast Start-up and Content Switching 511 Release 7 of PSS defines a number of extensions in terms of headers 512 and option tags (See Section 5.5 of [PSS-234]) for support of fast 513 start-up and switching of content for on-demand and live applications 514 built on top of PSS. Clients are enabled to reuse the existing RTSP 515 control session and RTP resources while switching to new content. 517 The RTSP headers are: 519 o Switch-Stream 520 o SDP-Requested 522 o Pipelined-Requests 524 The RTSP option tags are: 526 o 3gpp-pipelined 528 o 3gpp-switch 530 o 3gpp-switch-req-sdp 532 o 3gpp-switch-stream 534 8. IANA Considerations 536 8.1. SDP Registrations 538 IANA is requested to register the SDP attributes listed below in the 539 registry at http://www.iana.org/assignments/sdp-parameters. The 540 contact person for this registration is Magnus Westerlund 541 (magnus.westerlund@ericsson.com) Phone number +46 8 719 0000. 543 SDP Protocol Identifiers ("proto"): 545 Name: UDP/MBMS-FEC/RTP/AVP 546 Long form: 3GPP MBMS FEC protected RTP/AVP over UDP 547 Type of name: proto 548 Purpose: 3GPP MBMS defines a mechanism to provide block- 549 based FEC for UDP-based traffic. This solution 550 uses the SDP protocol "proto" identifier to 551 identify the media streams that use the FEC 552 shim layer. This protocol identifier indicates 553 that the FEC protected data is RTP using the 554 AVP profile. 555 Reference: RFCXXXX, 3GPP TS 26.346 557 Name: UDP/MBMS-FEC/RTP/SAVP 558 Long form: 3GPP MBMS FEC protected RTP/SAVP over UDP 559 Type of name: proto 560 Purpose: 3GPP MBMS defines a mechanism to provide block- 561 based FEC for UDP-based traffic. This solution 562 uses the SDP protocol "proto" identifier to 563 identify the media streams that use the FEC 564 shim layer. This protocol identifier indicates 565 that the FEC protected data is RTP using the 566 Secure AVP profile (SAVP). 567 Reference: RFCXXXX, 3GPP TS 26.346 569 Name: UDP/MBMS-REPAIR 570 Long form: 3GPP MBMS FEC repair symbols over UDP 571 Type of name: proto 572 Purpose: 3GPP MBMS defines a mechanism to provide block- 573 based FEC for UDP-based traffic. This solution 574 uses the SDP protocol "proto" identifier to 575 identify the media streams that use the FEC 576 shim layer. This protocol identifier indicates 577 that the FEC repair data is sent over UDP. 578 Reference: RFCXXXX, 3GPP TS 26.346 580 SDP Attribute ("att-field"): 582 Attribute name: X-predecbufsize 583 Long form: Pre-decoder buffer size 584 Type of name: att-field 585 Type of attribute: Media level only 586 Subject to charset: No 587 Purpose: See Section 4.1 588 Reference: 3GPP TS 26.234, Section 5.3.3.2 589 Values: See Reference 590 Attribute name: X-initpredecbufperiod 591 Long form: Pre-decoder initial buffering period 592 Type of name: att-field 593 Type of attribute: Media level only 594 Subject to charset: No 595 Purpose: See Section 4.1 596 Reference: 3GPP TS 26.234, Section 5.3.3.2 597 Values: See Reference 599 Attribute name: X-initpostdecbufperiod 600 Long form: Post-decoder initial buffering period 601 Type of name: att-field 602 Type of attribute: Media level only 603 Subject to charset: No 604 Purpose: See Section 4.1 605 Reference: 3GPP TS 26.234, Section 5.3.3.2 606 Values: See Reference 608 Attribute name: X-decbyterate 609 Long form: Peak decoding rate in bytes per second 610 Type of name: att-field 611 Type of attribute: Media level only 612 Subject to charset: No 613 Purpose: See Section 4.1 614 Reference: 3GPP TS 26.234, Section 5.3.3.2 615 Values: See Reference 617 Attribute name: 3gpp-videopostdecbufsize 618 Long form: Post decoder buffer size 619 Type of name: att-field 620 Type of attribute: Media level only 621 Subject to charset: No 622 Purpose: See Section 4.1 623 Reference: 3GPP TS 26.234, Section 5.3.3.2 624 Values: See Reference 626 Attribute name: framesize 627 Long form: Maximum Video Frame Size 628 Type of name: att-field 629 Type of attribute: Media level only 630 Subject to charset: No 631 Purpose: See Section 4.2 632 Reference: 3GPP TS 26.234, Section 5.3.3.2 633 Values: See Reference 635 Attribute name: 3GPP-Integrity-Key 636 Long form: 3GPP DRM Integrity Key 637 Type of name: att-field 638 Type of attribute: Session level only 639 Subject to charset: No 640 Purpose: See Section 4.3 641 Reference: 3GPP TS 26.234, Sections 5.3.3.2 and K.2.2.1 642 Values: See Reference 644 Attribute name: 3GPP-SRTP-Config 645 Long form: 3GPP DRM SRTP Configuration 646 Type of name: att-field 647 Type of attribute: Media level only 648 Subject to charset: No 649 Purpose: See Section 4.3 650 Reference: 3GPP TS 26.234, Sections 5.3.3.2 and K.2.2.2 651 Values: See Reference 653 Attribute name: 3GPP-SDP-Auth 654 Long form: 3GPP DRM Integrity SDP Authentication 655 Type of name: att-field 656 Type of attribute: Session level only 657 Subject to charset: No 658 Purpose: See Section 4.3 659 Reference: 3GPP TS 26.234, Sections 5.3.3.2 and K.2.2.3 660 Values: See Reference 662 Attribute name: alt 663 Long form: Alternative SDP line 664 Type of name: att-field 665 Type of attribute: Media level only 666 Subject to charset: No 667 Purpose: See Section 4.4 668 Reference: 3GPP TS 26.234, Section 5.3.3.3 669 Values: See Reference 671 Attribute name: alt-default-id 672 Long form: Default alternative ID 673 Type of name: att-field 674 Type of attribute: Media level only 675 Subject to charset: No 676 Purpose: See Section 4.4 677 Reference: 3GPP TS 26.234, Section 5.3.3.3 678 Values: See Reference 680 Attribute name: alt-group 681 Long form: Grouping of SDP Line alternatives 682 Type of name: att-field 683 Type of attribute: Session level only 684 Subject to charset: No 685 Purpose: See Section 4.4 686 Reference: 3GPP TS 26.234, Section 5.3.3.4 687 Values: See Reference 689 Attribute name: 3GPP-Adaptation-Support 690 Long form: 3GPP Adaptation Support 691 Type of name: att-field 692 Type of attribute: Media level only 693 Subject to charset: No 694 Purpose: See Section 4.5 695 Reference: 3GPP TS 26.234, Section 5.3.3.5 696 Values: See Reference 698 Attribute name: 3GPP-QoE-Metrics 699 Long form: 3GPP Quality of Experience Metrics 700 Type of name: att-field 701 Type of attribute: Session and Media level 702 Subject to charset: No 703 Purpose: See Section 4.6 704 Reference: 3GPP TS 26.234, Section 5.3.3.6 705 Values: See Reference 707 Attribute name: 3GPP-Asset-Information 708 Long form: 3GPP Asset Information 709 Type of name: att-field 710 Type of attribute: Session and Media level 711 Subject to charset: No 712 Purpose: See Section 4.7 713 Reference: 3GPP TS 26.234, Section 5.3.3.7 714 Values: See Reference 716 Attribute name: mbms-mode 717 Long form: MBMS Bearer Mode Declaration 718 Type of name: att-field 719 Type of attribute: Session and Media level 720 Subject to charset: No 721 Purpose: See Section 5.1 722 Reference: 3GPP TS 26.346, Section 7.3.2.7 723 Values: See Reference 725 Attribute name: mbms-flowid 726 Long form: FEC Flow ID 727 Type of name: att-field 728 Type of attribute: Media level 729 Subject to charset: No 730 Purpose: See Section 5.2 731 Reference: 3GPP TS 26.346, Section 8.3.1.9 732 Values: See Reference 733 Attribute name: mbms-repair 734 Long form: MBMS Repair 735 Type of name: att-field 736 Type of attribute: Session and Media level 737 Subject to charset: No 738 Purpose: See Section 5.3 739 Reference: 3GPP TS 26.346, Section 8.3.1.8 740 Values: See Reference 742 8.2. RTSP Registrations 744 IANA is requested to register the RTSP headers listed below in the 745 RTSP 1.0 registry table "RTSP/1.0 Headers" at: 747 http://www.iana.org/assignments/rtsp-parameters. 749 Note: This registry requires Standards document, preferably an IETF 750 RFC. The document that defines the registered headers below is a 751 technical standards document from 3GPP, although the request for 752 registration is submitted using this document to achieve further 753 information spreading within IETF. 755 The contact person for this registration is Magnus Westerlund 756 (magnus.westerlund@ericsson.com) Phone number +46 8 719 0000. 758 Header Name: 3GPP-Freshness-Token 759 Purpose: See Section K.2 of 3GPP TS 26.234 760 Methods: DESCRIBE Requests 761 Reference: Section K.2.2.4 of 3GPP TS 26.234 762 Values: See Reference 764 Header Name: 3GPP-Link-Char 765 Purpose: See Section 5.3.2.1 of 3GPP TS 26.234 766 Methods: SETUP, PLAY, OPTIONS or SET_PARAMETER Requests 767 Reference: Section 5.3.2.1 of 3GPP TS 26.234 768 Values: See Reference 770 Header Name: 3GPP-Adaptation 771 Purpose: See Section 5.3.2.2 of 3GPP TS 26.234 772 Methods: SETUP, PLAY, OPTIONS, or SET_PARAMETER Requests 773 and Responses 774 Reference: Section 5.3.2.2 of 3GPP TS 26.234 775 Values: See Reference 777 Header Name: 3GPP-QoE-Metrics 778 Purpose: See Section 5.3.2.3.1 of 3GPP TS 26.234 779 Methods: SETUP, PLAY, OPTIONS, or SET_PARAMETER Requests 780 and Responses 781 Reference: Section 5.3.2.3.1 of 3GPP TS 26.234 782 Values: See Reference 784 Header Name: 3GPP-QoE-Feedback 785 Purpose: See Section 5.3.2.3.2 of 3GPP TS 26.234 786 Methods: SET_PARAMETER, PAUSE, or TEARDOWN Requests 787 Reference: Section 5.3.2.3.2 of 3GPP TS 26.234 788 Values: See Reference 790 Header Name: Switch-Stream 791 Purpose: See Section 5.5.4.2 of 3GPP TS 26.234 792 Methods: PLAY Requests and Responses 793 Reference: Section 5.5.4.2 of 3GPP TS 26.234 794 Values: See Reference 796 Header Name: SDP-Requested 797 Purpose: See Section 5.5.4.4 of 3GPP TS 26.234 798 Methods: PLAY Requests 799 Reference: Section 5.5.4.4 of 3GPP TS 26.234 800 Values: See Reference 802 Header Name: Pipelined-Requests 803 Purpose: See Section 5.5.3 of 3GPP TS 26.234 804 Methods: SETUP and PLAY Requests 805 Reference: Section 5.5.3 of 3GPP TS 26.234 806 Values: See Reference 808 Header Name: x-predecbufsize 809 Purpose: See Section 5.3.2.4 of 3GPP TS 26.234 810 Methods: PLAY Response 811 Reference: Section 5.3.2.4 of 3GPP TS 26.234 812 Values: See Reference 814 Header Name: x-initpredecbufperiod 815 Purpose: See Section 5.3.2.4 of 3GPP TS 26.234 816 Methods: PLAY Response 817 Reference: Section 5.3.2.4 of 3GPP TS 26.234 818 Values: See Reference 820 Header Name: x-initpostdecbufperiod 821 Purpose: See Section 5.3.2.4 of 3GPP TS 26.234 822 Methods: PLAY Response 823 Reference: Section 5.3.2.4 of 3GPP TS 26.234 824 Values: See Reference 826 Header Name: 3gpp-videopostdecbufsize 827 Purpose: See Section 5.3.2.4 of 3GPP TS 26.234 828 Methods: PLAY Response 829 Reference: Section 5.3.2.4 of 3GPP TS 26.234 830 Values: See Reference 832 Header Name: Supported 833 Purpose: See Section 5.5.2.2.2 of 3GPP TS 26.234 834 Methods: Any Request and Response 835 Reference: Section 5.5.2.2.2 of 3GPP TS 26.234 836 Values: See Reference 838 IANA is requested to register the RTSP Option tags (option tags) 839 listed below in the RTSP 1.0 registry table for RTSP/1.0 Option Tags 841 http://www.iana.org/assignments/rtsp-parameters. 843 Option tag: 3gpp-pipelined 844 Purpose: See Section 5.5.3 of 3GPP TS 26.234 845 Applies to: Client and Server 846 Reference: Section 5.5.3 of 3GPP TS 26.234 847 Values: See Reference 849 Option tag: 3gpp-switch 850 Purpose: See Section 5.5.4.2 of 3GPP TS 26.234 851 Applies to: Client and Server 852 Reference: Section 5.5.4.2 of 3GPP TS 26.234 853 Values: See Reference 855 Option tag: 3gpp-switch-req-sdp 856 Purpose: See Section 5.5.4.4 of 3GPP TS 26.234 857 Applies to: Client and Server 858 Reference: Section 5.5.4.4 of 3GPP TS 26.234 859 Values: See Reference 861 Option tag: 3gpp-switch-stream 862 Purpose: See Section 5.5.4.5 of 3GPP TS 26.234 863 Applies to: Client and Server 864 Reference: Section 5.5.4.5 of 3GPP TS 26.234 865 Values: See Reference 867 9. Security Considerations 869 SDP attributes are subject to modification by an attacker unless they 870 are integrity protected and authenticated. The security 871 consideration of the SDP specification [RFC4566] should be reviewed 872 in this regard. The registered SDP attributes are vulnerable to 873 modification attacks or removal, which may result in problems of 874 serious nature, including failure to use service and reduced quality. 876 The registered RTSP headers are also vunerable to insertion, deletion 877 or modification attacks similar to SDP attributes. Also in this 878 case, it can result in failure of the service or reduced quality of 879 streaming content. 881 The three SDP protocol identifiers do not by themselves introduce any 882 additional security threats that don't exist for other protocol 883 identifiers in SDP. The media stream and the used protocols 884 identified and configured by the SDP protocol identifier may however 885 contain security issues by themselves. 887 10. References 889 10.1. Normative References 891 [MBMS] 3GPP TS 26.346 version 7.10.0 (2009-03), "Multimedia 892 Broadcast/Multicast Service (MBMS); Protocols and codecs". 894 [PSS-234] 3GPP TS 26.234 version 7.7.0 (2009-03), "Transparent end- 895 to-end Packet-switched Streaming Service (PSS); Protocols 896 and codecs,". 898 [PSS-3GP] 3GPP TS 26.244 version 7.3.0 (2007-12), "Transparent end- 899 to-end packet switched streaming service (PSS); 3GPP file 900 format (3GP)". 902 [RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768, 903 August 1980. 905 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 906 Requirement Levels", BCP 14, RFC 2119, March 1997. 908 [RFC3551] Schulzrinne, H. and S. Casner, "RTP Profile for Audio and 909 Video Conferences with Minimal Control", STD 65, RFC 3551, 910 July 2003. 912 [RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. 913 Norrman, "The Secure Real-time Transport Protocol (SRTP)", 914 RFC 3711, March 2004. 916 10.2. Informative References 918 [AES] ""Advanced Encryption Standard (AES)", FIPS PUB 197, 919 http://www.nist.gov/aes/.". 921 [PSS-233] 3GPP TS 26.233 version 7.0.0 (2007-06), "Transparent end- 922 to-end packet switched streaming service (PSS) General 923 Description". 925 [RFC2326] Schulzrinne, H., Rao, A., and R. Lanphier, "Real Time 926 Streaming Protocol (RTSP)", RFC 2326, April 1998. 928 [RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model 929 with Session Description Protocol (SDP)", RFC 3264, 930 June 2002. 932 [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session 933 Description Protocol", RFC 4566, July 2006. 935 [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data 936 Encodings", RFC 4648, October 2006. 938 10.3. 940 Authors' Addresses 942 Magnus Westerlund 943 Ericsson 944 Farogatan 6 945 Stockholm, SE-164 80 946 SWEDEN 948 Phone: +46 10 7190000 949 Fax: +46 10 757 55 50 950 Email: magnus.westerlund@ericsson.com 952 Per Frojdh 953 Ericsson 954 Farogatan 6 955 Stockholm, SE-164 80 956 SWEDEN 958 Phone: +46 10 7190000 959 Fax: +46 10 757 55 50 960 Email: per.frojdh@ericsson.com