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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Missing Reference: 'RFCXXXX' is mentioned on line 970, but not defined == Unused Reference: 'RFC5234' is defined on line 754, but no explicit reference was found in the text == Unused Reference: 'G.1082' is defined on line 776, but no explicit reference was found in the text -- Possible downref: Non-RFC (?) normative reference: ref. 'ATSC' ** Obsolete normative reference: RFC 4566 (Obsoleted by RFC 8866) ** Obsolete normative reference: RFC 5226 (Obsoleted by RFC 8126) Summary: 2 errors (**), 0 flaws (~~), 4 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group A. Clark 3 Internet-Draft Telchemy 4 Intended status: Standards Track Q. Wu 5 Expires: August 30, 2014 Huawei 6 R. Schott 7 Deutsche Telekom 8 G. Zorn 9 Network Zen 10 February 26, 2014 12 RTP Control Protocol (RTCP) Extended Report (XR) Blocks for MOS Metric 13 Reporting 14 draft-ietf-xrblock-rtcp-xr-qoe-16 16 Abstract 18 This document defines an RTP Control Protocol (RTCP) Extended Report 19 (XR) Block including two new segment types and associated SDP 20 parameters that allow the reporting of mean opinion score (MOS) 21 Metrics for use in a range of RTP applications. 23 Status of this Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF). Note that other groups may also distribute 30 working documents as Internet-Drafts. The list of current Internet- 31 Drafts is at http://datatracker.ietf.org/drafts/current/. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 This Internet-Draft will expire on August 30, 2014. 40 Copyright Notice 42 Copyright (c) 2014 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents 47 (http://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with respect 50 to this document. Code Components extracted from this document must 51 include Simplified BSD License text as described in Section 4.e of 52 the Trust Legal Provisions and are provided without warranty as 53 described in the Simplified BSD License. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 58 1.1. MOS Metrics Report Block . . . . . . . . . . . . . . . . . 4 59 1.2. RTCP and RTCP XR Reports . . . . . . . . . . . . . . . . . 4 60 1.3. Performance Metrics Framework . . . . . . . . . . . . . . 4 61 1.4. Applicability . . . . . . . . . . . . . . . . . . . . . . 4 62 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 63 2.1. Standards Language . . . . . . . . . . . . . . . . . . . . 5 64 3. MoS Metrics Block . . . . . . . . . . . . . . . . . . . . . . 5 65 3.1. Report Block Structure . . . . . . . . . . . . . . . . . . 6 66 3.2. Definition of Fields in MoS Metrics Block . . . . . . . . 7 67 3.2.1. Single Channel audio/video per SSRC Segment . . . . . 8 68 3.2.2. Multi-Channel audio per SSRC Segment . . . . . . . . . 9 69 4. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 11 70 4.1. SDP rtcp-xr-attrib Attribute Extension . . . . . . . . . . 11 71 4.2. Offer/Answer Usage . . . . . . . . . . . . . . . . . . . . 13 72 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 73 5.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 15 74 5.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 15 75 5.3. The SDP calgextmap Attribute . . . . . . . . . . . . . . . 15 76 5.4. New registry of calculation algorithms . . . . . . . . . . 16 77 6. Security Considerations . . . . . . . . . . . . . . . . . . . 17 78 7. Authors . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 79 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17 80 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18 81 9.1. Normative References . . . . . . . . . . . . . . . . . . . 18 82 9.2. Informative References . . . . . . . . . . . . . . . . . . 18 83 Appendix A. Metrics represented using RFC6390 Template . . . . . 20 84 Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 23 85 B.1. draft-ietf-xrblock-rtcp-xr-qoe-15 . . . . . . . . . . . . 23 86 B.2. draft-ietf-xrblock-rtcp-xr-qoe-14 . . . . . . . . . . . . 23 87 B.3. draft-ietf-xrblock-rtcp-xr-qoe-10 . . . . . . . . . . . . 23 88 B.4. draft-ietf-xrblock-rtcp-xr-qoe-09 . . . . . . . . . . . . 23 89 B.5. draft-ietf-xrblock-rtcp-xr-qoe-08 . . . . . . . . . . . . 23 90 B.6. draft-ietf-xrblock-rtcp-xr-qoe-07 . . . . . . . . . . . . 24 91 B.7. draft-ietf-xrblock-rtcp-xr-qoe-06 . . . . . . . . . . . . 24 92 B.8. draft-ietf-xrblock-rtcp-xr-qoe-04 . . . . . . . . . . . . 24 93 B.9. draft-ietf-xrblock-rtcp-xr-qoe-03 . . . . . . . . . . . . 24 94 B.10. draft-ietf-xrblock-rtcp-xr-qoe-02 . . . . . . . . . . . . 24 95 B.11. draft-ietf-xrblock-rtcp-xr-qoe-01 . . . . . . . . . . . . 24 96 B.12. draft-ietf-xrblock-rtcp-xr-qoe-00 . . . . . . . . . . . . 25 97 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 25 99 1. Introduction 101 1.1. MOS Metrics Report Block 103 This document defines a new block type to augment those defined in 104 [RFC3611], for use in a range of RTP applications. 106 The new block type provides information on media quality using one of 107 several standard metrics (i.e. Mean Opinion Score(MOS)). 109 The metrics belong to the class of application level metrics defined 110 in [RFC6792]. 112 1.2. RTCP and RTCP XR Reports 114 The use of RTCP for reporting is defined in [RFC3550]. RFC3611 115 defined an extensible structure for reporting using an RTCP Extended 116 Report (XR). This document defines a new Extended Report block for 117 use with [RFC3550] and [RFC3611]. 119 1.3. Performance Metrics Framework 121 The Performance Metrics Framework [RFC6390] provides guidance on the 122 definition and specification of performance metrics. The RTP 123 Monitoring Architectures [RFC6792] provides guidelines for reporting 124 block format using RTCP XR. The XR block type described in this 125 document are in accordance with the guidelines in [RFC6390] and 126 [RFC6792]. 128 1.4. Applicability 130 The MOS Metrics Report Block can be used in any application of RTP 131 for which QoE (Quality of Experience) measurement algorithms are 132 defined. 134 The factors that affect real-time audio/video application quality can 135 be split into two categories. The first category consists of 136 transport-specific factors such as packet loss, delay and jitter 137 (which also translates into losses in the playback buffer). The 138 factors in the second category consists of content and codec related 139 factors such as codec type and loss recovery technique, coding bit 140 rate, packetization scheme, and content characteristics 142 Transport-specific factors may be insufficient to infer real time 143 media quality as codec related parameters and the interaction between 144 transport problems and application layer protocols can have a 145 substantial effect on observed media quality. Media quality may be 146 measured using algorithm that directly compare input and output media 147 streams, or may be estimated using algorithms that model the 148 interaction between media quality, protocol and encoded content. 149 Media quality is commonly expressed in terms of Mean Opinion Score 150 (MOS) however is also represented by a range of indexes and other 151 scores. 153 The measurement of media quality has a number of applications: 154 o Detecting problems with media delivery or encoding that is 155 impacting user perceived quality. 156 o Tuning the content encoder algorithm to satisfy real time data 157 quality requirements. 158 o Determining which system techniques to use in a given situation 159 and when to switch from one technique to another as system 160 parameters change (for example as discussed in [P.1082]). 161 o Pre-qualifying a network to assess its ability to deliver an 162 acceptable end-user perceived quality level. 164 2. Terminology 166 2.1. Standards Language 168 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 169 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 170 document are to be interpreted as described in RFC 2119 [RFC2119]. 172 The terminology used is 174 Numeric formats X:Y 176 where X the number of bits prior to the decimal place and Y the 177 number of bits after the decimal place. 178 Hence 8:8 represents an unsigned number in the range 0.0 to 179 255.996 with a granularity of 0.0039. 0:16 represents a proper 180 binary fraction with range 181 0.0 to 1 - 1/65536 = 0.9999847 182 though note that use of flag values at the top of the numeric 183 range slightly reduces this upper limit. For example, if the 184 16- bit values 0xfffe and 0xffff are used as flags for "over- 185 range" and "unavailable" conditions, a 0:16 quantity has range 186 0.0 to 1 - 3/65536 = 0.9999542 188 3. MoS Metrics Block 190 Multimedia application MOS Metric is commonly expressed as a MOS 191 ("Mean Opinion Score"), MOS is usually on a scale from 1 to 5, in 192 which 5 represents excellent and 1 represents unacceptable however 193 can use other ranges (for example 0 to 10 ) . The term "MOS score" 194 originates from subjective testing, and is used to refer to the Mean 195 of a number of individual Opinion Scores. There is therefore a well 196 understood relationship between MOS and user experience, hence the 197 industry commonly uses MOS as the scale for objective test results. 198 Subjective tests can be used for measuring live network traffic 199 however the use of objective or algorithmic measurement techniques 200 allows much larger scale measurements to be made. Within the scope 201 of this document, MOS scores are obtained using objective or 202 estimation algorithms. ITU-T or ITU-R recommendations (e.g., 203 [BS.1387-1],[G.107],[G.107.1],[P.862],[P.862.1],[P.862.2],[P.863],[P. 204 564],[G.1082],[P.1201.1],[P.1201.2],[P.1202.1],[P.1202.2]) define 205 methodologies for assessment of the performance of audio and video 206 streams. Other international and national standards organizations 207 such as EBU, ETSI, IEC and IEEE also define QoE algorithms and 208 methodologies, and the intent of this document is not to restrict its 209 use to ITU recommendations but to suggest that ITU recommendations be 210 used where they are defined. 212 This block reports the media quality in the form of a 1-5 MOS range 213 however does not report the MoS score that include parameters outside 214 the scope of the RTP stream, for example signaling performance, mean 215 time to repair (MTTR) or other factors that may affect the overall 216 user experience. 218 The MOS Metric reported in this block gives a numerical indication of 219 the perceived quality of the received media stream, which is 220 typically measured at the receiving end of the RTP stream. Instances 221 of this Metrics Block refer by Synchronization source (SSRC) to the 222 separate auxiliary Measurement Information block [RFC6776] which 223 describes measurement periods in use (see RFC6776 section 4.2). 225 This Metrics Block relies on the measurement period in the 226 Measurement Information block indicating the span of the report. 227 Senders MUST send this block in the same compound RTCP packet as the 228 measurement information block. Receivers MUST verify that the 229 measurement period is received in the same compound RTCP packet as 230 this Metrics Block. If not, this Metrics Block MUST be discarded. 232 3.1. Report Block Structure 234 The MOS Metrics Block has the following format: 236 0 1 2 3 237 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 238 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 239 | BT=MMB | I | Reserved | Block Length | 240 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 241 | SSRC of source | 242 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 243 | Segment 1 | 244 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 245 | Segment 2 | 246 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 247 .................. 248 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 249 | Segment n | 250 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 252 3.2. Definition of Fields in MoS Metrics Block 254 Block type (BT): 8 bits 256 The MOS Metrics Block is identified by the constant . 258 Interval Metric flag (I): 2 bits 260 This field is used to indicate whether the MOS Metrics are 261 Sampled, Interval or Cumulative [RFC6792]: 263 I=10: Interval Duration - the reported value applies to the 264 most recent measurement interval duration between successive 265 metrics reports. 266 I=11: Cumulative Duration - the reported value applies to the 267 accumulation period characteristic of cumulative measurements. 268 I=01: Sampled Value - the reported value is a sampled 269 instantaneous value. 270 I=00: Reserved 272 In this document, MOS Metrics MAY be reported for intervals or for 273 the duration of the media stream (cumulative). The value I=01, 274 indicating a sampled value, MUST NOT be sent, and MUST be 275 discarded when received. 277 Reserved: 6 bits 279 This field is reserved for future definition. In the absence of 280 such a definition, the bits in this field MUST be set to zero and 281 ignored by the receiver (See RFC6709 section 4.2). 283 Block Length: 16 bits 285 The length of this report block in 32-bit words, minus one. For 286 the MOS Metrics Block, the block length is variable length. 288 SSRC of source: 32 bits 290 As defined in Section 4.1 of [RFC3611]. 292 Segment i: 32 bits 294 There are two segment types defined in this document: single 295 stream Audio/Video per SSRC segment, multi-channel audio per SSRC 296 segment. Multi-channel audio per SSRC segment is used to deal 297 with the case where Multi-channel audios are carried in one RTP 298 stream while single channel Audio/Video per SSRC segment is used 299 to deal with the case where each media stream is identified by 300 SSRC and sent in separate RTP stream. The leftmost bit of the 301 segment determines its type. If the leftmost bit of the segment 302 is zero, then it is single channel segment. If the leftmost bit 303 is one, then it is multi-channel audio segment. Note that two 304 segment types can not be present in the same metric block. 306 3.2.1. Single Channel audio/video per SSRC Segment 308 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 309 |S| CAID | PT | MOS Value | 310 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 312 Segment Type (S): 1 bit 314 This field is used to identify the segment type used in this 315 report block. A zero identifies this as a single channel Audio/ 316 Video per SSRC segment. Single channel means there is only one 317 media stream carried in one RTP stream. The single channel Audio/ 318 Video per SSRC segment can be used to report the MOS value 319 associated with the media stream identified by SSRC. If there are 320 multiple media streams and they want to use the single channel 321 Audio/Video per SSRC segment to report the MOS value, they should 322 be carried in the separate RTP streams with each identified by 323 different SSRC. In this case, multiple MOS Metrics Blocks are 324 required to report the MOS value corresponding to each media 325 stream using single channel Audio/Video per SSRC segment in the 326 same RTCP XR packet. 328 Calculation Algorithm ID (CAID) : 8 bits 330 The 8-bit CAID is the session specific reference to the 331 calculation algorithm and associated qualifiers indicated in SDP 332 (see Section 4.1) and used to compute the MOS score for this 333 segment. 335 Payload Type (PT): 7 bits 337 MOS Metrics reporting depends on the payload format in use. This 338 field identifies the RTP payload type in use during the reporting 339 interval. The binding between RTP payload types and RTP payload 340 formats is configured via a signalling protocol, for example an 341 SDP offer/answer exchange. If the RTP payload type used is 342 changed during an RTP session, separate reports SHOULD be sent for 343 each RTP payload type, with corresponding measurement information 344 blocks indicating the time period to which they relate. 346 Note that the use of this Report Block with MPEG Transport streams 347 carried over RTP is undefined as each MPEG Transport stream may 348 use distinct audio or video codecs and the indication of the 349 encoding of these is within the MPEG Transport stream and does not 350 use RTP payloads. 352 MOS Value: 16 bits 354 The estimated Mean Opinion Score (MOS) for multimedia application 355 performance is defined as including the effects of delay, loss, 356 discard, jitter and other effects that would affect media quality. 357 This is a unsigned fixed-point 7:9 value representing the MOS, 358 allowing the MOS score up to 127 in the integer part. MOS ranges 359 are defined as part of the specification of the MOS estimation 360 algorithm (Calculation Algorithm in this document), and are 361 normally ranges like 1-5, 0-10, or 0-100. Two values are 362 reserved: A value of 0xFFFE indicates out of range and a value of 363 0xFFFF indicates that the measurement is unavailable. Values 364 outside of the range defined by the Calculation Algorithm, other 365 than the two reserved values, MUST NOT be sent and MUST be ignored 366 by the receiving system. 368 3.2.2. Multi-Channel audio per SSRC Segment 370 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 371 |S| CAID | PT |CHID | MOS Value | 372 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 374 Segment Type (S): 1 bit 376 This field is used to identify the segment type used in this 377 report block. A one identifies this as a multi-channel audio 378 segment. 380 Calculation Algorithm ID (CAID) : 8 bits 382 The 8-bit CAID is the session specific reference to the 383 calculation algorithm and associated qualifiers indicated in SDP 384 (see Section 4.1) and used to compute the MOS score for this 385 segment. 387 Payload Type (PT): 7 bits 389 As defined in Section 3.2.1 of this document 391 Channel Identifier (CHID): 3 bits 393 If multiple channels of audio are carried in one RTP stream, each 394 channel of audio will be viewed as a independent channel(e.g., 395 left channel audio, right channel audio). This field is used to 396 identify each channel carried in the same media stream. The 397 default Channel mapping follows static ordering rule described in 398 the section 4.1 of [RFC3551]. However there are some payload 399 formats that use different channel mappings, e.g., AC-3 audio over 400 RTP [RFC4184] only follow AC-3 channel order scheme defined in 401 [ATSC]. Enhanced AC-3 Audio over RTP [RFC4598] uses dynamic 402 channel transform mechanism. In order that the appropriate 403 channel mapping can be determined, MOS metrics reports need to be 404 tied to an RTP payload format, i.e., including the payload type of 405 the reported media according to [RFC6792] and using Payload Type 406 to determine the appropriate channel mapping. 408 MOS Value: 13 bits 410 The estimated Mean Opinion Score (MOS) for multimedia application 411 performance is defined as including the effects of delay, loss, 412 discard, jitter and other effects that would affect media quality. 413 This is a unsigned fixed-point 7:6 value representing the MOS, 414 allowing the MOS score up to 127 in the integer part. MOS ranges 415 are defined as part of the specification of the MOS estimation 416 algorithm (Calculation Algorithm in this document), and are 417 normally ranges like 1-5, 0-10, or 0-100. Two values are 418 reserved: A value of 0x1FFE indicates out of range and a value of 419 0x1FFF indicates that the measurement is unavailable. Values 420 outside of the range defined by the Calculation Algorithm, other 421 than the two reserved values, MUST NOT be sent and MUST be ignored 422 by the receiving system. 424 4. SDP Signaling 426 [RFC3611]defines the use of SDP (Session Description Protocol) 427 [RFC4566] for signaling the use of XR blocks. However XR blocks MAY 428 be used without prior signaling (see section 5 of RFC3611). 430 4.1. SDP rtcp-xr-attrib Attribute Extension 432 This section augments the SDP [RFC4566] attribute "rtcp-xr" defined 433 in [RFC3611] by providing an additional value of "xr-format" to 434 signal the use of the report block defined in this document. Within 435 the "xr-format", the syntax element "calgextmap" is an attribute as 436 defined in [RFC4566] and used to signal the mapping of the local 437 identifier (CAID) in the segment extension defined in section 3.2 to 438 the calculation algorithm. Specific extensionattributes are defined 439 by the specification that defines a specific extension name; there 440 might be several. 442 xr-format =/ xr-mos-block 443 xr-mos-block = "mos-metric" ["=" calgextmap *("," calgextmap)] 444 calgextmap = mapentry "=" extensionname [SP extentionattributes] 445 direction = "sendonly" / "recvonly" / "sendrecv" / "inactive" 446 mapentry = "calg:" 1*3 DIGIT ["/" direction] 447 ; Values in the range 1-255 are valid 448 ; if needed, 0 can be used to indicate that 449 ; an algorithm is rejected 450 extensionname = "P564";ITU-T P.564 Compliant Algorithm [P.564] 451 / "G107";ITU-T G.107 [G.107] 452 / "G107_1";ITU-T G.107.1 [G.107.1] 453 / "TS101_329";ETSI TS 101 329-5 Annex E [ ETSI] 454 /"JJ201_1 ";TTC JJ201.1 [TTC] 455 /"P1201_1";ITU-T P.1201.2 [P.1201.1] 456 /"P1201_2";ITU-T P.1201.2 [P.1201.2] 457 /"P1202_1";ITU-T P.1202.1 [P.1202.1] 458 /"P1202_2";ITU-T P.1202.2 [P.1202.2] 459 /"P.862.2";ITU-T P.862.2 [P.862.2] 460 /"P.863"; ITU-T P.863 [P.863] 461 / non-ws-string 462 extensionattributes = mosref 463 /attributes-ext 464 mosref = "mosref=" ("l"; lower resolution 465 /"m"; middle resolution 466 / "h";higher resolution 467 / non-ws-string) 468 attributes-ext = non-ws-string 469 SP = 470 non-ws-string = 1*(%x21-FF) 472 Each local identifier (CAID)of calculation algorithm used in the 473 segment defined in the section 3.2 is mapped to a string using an 474 attribute of the form: 476 a=calg: ["/"] [] 478 where is a calculation algorithm name, as above, is 479 the local identifier (CAID)of the calculation algorithm associated 480 with the segment defined in this document and is an integer in the 481 valid range inclusive. 483 Example: 484 a=rtcp-xr:mos-metric=calg:1=G107,calg:2=P1202_1 486 A usable mapping MUST use IDs in the valid range, and each ID in this 487 range MUST be unique and used only once for each stream or each 488 channel in the stream. 490 The mapping MUST be provided per media stream (in the media-level 491 section(s) of SDP, i.e., after an "m=" line). 493 The syntax element "mosref" is referred to the media resolution 494 relative reference and has three valules 'l','m','h'.(e.g., 495 Narrowband (3.4kHz) Speech and Standard Definition (SD) or lower 496 Resolution Video have 'l' resolution, Super Wideband (>14kHz) Speech 497 or higher and High Definition (HD) or higher Resolution Video have 498 'h' Resolution, Wideband speech(7khz) and Video with resolution 499 between SD and HD has 'm' resolution). The MOS score reported in the 500 MOS metrics block might vary with the MOS reference; For example, MOS 501 values for narrowband, wideband, super wideband codecs occupy the 502 same range but SHOULD be reported in different value. For video 503 application, MOS scores for SD resolution, HD resolution video also 504 occupy the same ranges and SHOULD be reported in different value. 506 4.2. Offer/Answer Usage 508 When SDP is used in offer-answer context, the SDP Offer/Answer usage 509 defined in [RFC3611] applies. In the offer answer context, the 510 signaling described above might be used in three ways: 512 o asymmetric behavior (segment extensions sent in only one 513 direction), 514 o the offer of mutually exclusive alternatives, or 515 o the offer of more segments than can be sent in a single session. 517 A direction attribute MAY be included in a calgextmap; without it, 518 the direction implicitly inherits, of course, from the RTCP stream 519 direction. 521 Segment extensions, with their directions, MAY be signaled for an 522 "inactive" stream. An extension direction MUST be compatible with 523 the stream direction. If a segment extension in the SDP offer is 524 marked as "sendonly" and the answerer desires to receive it, the 525 extension MUST be marked as "recvonly" in the SDP answer. An 526 answerer that has no desire to receive the extension or does not 527 understand the extension SHOULD NOT include it in the SDP answer. 529 If a segment extension is marked as "recvonly" in the SDP offer and 530 the answerer desires to send it, the extension MUST be marked as 531 "sendonly" in the SDP answer. An answerer that has no desire to, or 532 is unable to, send the extension SHOULD NOT include it in the SDP 533 answer. 535 If a segment extension is offered as "sendrecv", explicitly or 536 implicitly, and asymmetric behavior is desired, the SDP MAY be 537 modified to modify or add direction qualifiers for that segment 538 extension. 540 A mosref attribute and MOS type attribute MAY be included in an 541 calgextmap; without it, the mosref and most type attribute implicitly 542 inherits, of course, from the name attribute (e.g., P.1201.1 543 [P.1201.1] indicates lower resolution used while P.1201.2 [P.1201.2] 544 indicates higher resolution used) or payload type carried in the 545 segment extension (e.g.,EVRC-WB [RFC5188] indicates using Wideband 546 Codec). However not all payload types or MOS algorithm names 547 indicate resolution to be used and MOS type to be used. If an 548 answerer receives an offer with an mosref attribute value it doesn't 549 support (e.g.,the answerer only supports "l" and receives "h"from 550 offerer), the answer SHOULD reject the mosref attribute value offered 551 by the offerer. 553 If the answerer wishes to reject a mosref attribute offered by the 554 offerer, it sets identifiers associated with segment extensions in 555 the answer to the value in the range 4096-4351. The rejected answer 556 MUST contain 'mosref ' attribute whose value is the value of the SDP 557 offer. 559 Local identifiers in the valid range inclusive in an offer or answer 560 must not be used more than once per media section. A session update 561 MAY change the direction qualifiers of segment extensions under use. 562 A session update MAY add or remove segment extension(s). Identifiers 563 values in the valid range MUST NOT be altered (remapped). 565 If a party wishes to offer mutually exclusive alternatives, then 566 multiple segment extensions with the same identifier in the 567 (unusable) range 4096-4351 MAY be offered; the answerer SHOULD select 568 at most one of the offered extensions with the same identifier, and 569 remap it to a free identifier in the valid range, for that extension 570 to be usable. Note that two segment types defined in section 3 are 571 also two exclusive alternatives. 573 If more segment extensions are offered in the valid range, the 574 answerer SHOULD choose those that are desired, and place the offered 575 identifier value "as is" in the SDP answer. 577 Similarly, if more segment extensions are offered than can be fit in 578 the valid range, identifiers in the range 4096-4351 MAY be offered; 579 the answerer SHOULD choose those that are desired, and remap them to 580 a free identifier in the valid range. 582 Note that the range 4096-4351 for these negotiation identifiers is 583 deliberately restricted to allow expansion of the range of valid 584 identifiers in future. Segment extensions with an identifier outside 585 the valid range cannot, of course, be used. 587 Example (port numbers, RTP profiles, payload IDs and rtpmaps, etc. 588 all omitted for brevity): 590 The offer: 592 a=rtcp-xr:mos-metric=calg:4906=P1201_l,calg:4906=P1202_l, calg: 593 4907=G107 595 The answerer is interested in transmission P.1202.1 on lower 596 resolution application, but doesn't support P.1201.1 on lower 597 resolution application at all. It is interested in transmission 598 G.107. It therefore adjusts the declarations: 600 a=rtcp-xr:mos-metric=calg:1=P1202_l,calg:2=G107 602 5. IANA Considerations 604 New block types for RTCP XR are subject to IANA registration. For 605 general guidelines on IANA considerations for RTCP XR, refer to 606 [RFC3611]. 608 5.1. New RTCP XR Block Type value 610 This document assigns the block type value MMB in the IANA " RTP 611 Control Protocol Extended Reports (RTCP XR) Block Type Registry" to 612 the "MOS Metrics Block". 614 [Note to RFC Editor: please replace MMB with the IANA provided RTCP 615 XR block type for this block.] 617 5.2. New RTCP XR SDP Parameter 619 This document also registers a new parameter "mos-metric" in the " 620 RTP Control Protocol Extended Reports (RTCP XR) Session Description 621 Protocol (SDP) Parameters Registry". 623 5.3. The SDP calgextmap Attribute 625 This section contains the information required by [RFC4566] for an 626 SDP attribute. 627 o contact name, email address: RAI Area Directors 628 629 o attribute name (as it will appear in SDP): calgextmap 630 o long-form attribute name in English: calculation algorithm map 631 definition 633 o type of attribute (session level, media level, or both): both 634 o whether the attribute value is subject to the charset attribute: 635 not subject to the charset attribute 636 o a one-paragraph explanation of the purpose of the attribute: This 637 attribute defines the mapping from the local identifier (CAID) in 638 the segment extension defined in section 3.2 into the calculation 639 algorithm name as documented in specifications and appropriately 640 registered. 641 o a specification of appropriate attribute values for this 642 attribute: see RFC xxxx. 644 5.4. New registry of calculation algorithms 646 This document creates a new registry to be called "RTCP XR MOS Metric 647 block - multimedia application Calculation Algorithm" as a sub- 648 registry of the "RTP Control Protocol Extended Reports (RTCP XR) 649 Block Type Registry". This registry applies to the multimedia 650 session where each type of media are sent in a separate RTP stream 651 and also applies to the session where Multi-channel audios are 652 carried in one RTP stream. Policies for this new registry are as 653 follows: 655 o The information required to support this assignment is an 656 unambiguous definition of the new metric, covering the base 657 measurements and how they are processed to generate the reported 658 metric. 660 o The review process for the registry is "Specification Required" as 661 described in Section 4.1 of [RFC5226]. 663 o Entries in the registry are identified by entry name and mapped to 664 the local identifier (CAID) in the segment extension defined in 665 section 3.2. 667 o Registration Template 669 The following information must be provided with each registration: 670 * Name: A string uniquely and unambiguously identifying the 671 Calculation algorithm for use in protocols. 672 * Name Description: A valid Description of the Calculation 673 algorithm name. 674 * Reference: The reference which defines the calculation 675 algorithm corresponding to the Name and Name Description. 676 * Type: The media type to which the calculation algorithm is 677 applied 679 o Initial assignments are as follows: 681 Name Name Description Reference Type 682 ========= =================================== ========== ==== 683 P564 ITU-T P.564 Compliant Algorithm [P.564] Voice 684 G107 ITU-T G.107 [G.107] Voice 685 TS101_329 ETSI TS 101 329-5 Annex E [ETSI] Voice 686 JJ201_1 TTC JJ201.1 [TTC] Voice 687 G107_1 ITU-T G.107.1 [G.107.1] Voice 688 P862 ITU-T P.862 [P.862] Voice 689 P862_2 ITU-T P.862.2 [P.862.2] Voice 690 P863 ITU-T P.863 [P.863] Voice 691 P1201_1 ITU-T P.1201.1 [P.1201.1] Multimedia 692 P1201_2 ITU-T P.1201.2 [P.1201.2] Multimedia 693 P1202_1 ITU-T P.1202.1 [P.1202.1] Video 694 P1202_2 ITU-T P.1202.2 [P.1202.2] Video 696 6. Security Considerations 698 The new RTCP XR report blocks proposed in this document introduces no 699 new security considerations beyond those described in [RFC3611]. 701 7. Authors 703 This draft merges ideas from two drafts addressing the MOS Metric 704 Reporting issue. The authors of these drafts are listed below (in 705 alphabetical order): 707 Alan Clark < alan.d.clark@telchemy.com > 708 Geoff Hunt < r.geoff.hunt@gmail.com > 709 Martin Kastner < martin.kastner@telchemy.com > 710 Qin Wu < sunseawq@huawei.com > 711 Roland Schott < roland.schott@telekom.de > 712 Glen Zorn < gwz@net-zen.net > 713 Kai Lee < leekai@ctbri.com.cn > 715 8. Acknowledgements 717 The authors gratefully acknowledge the comments and contributions 718 made by Bruce Adams, Philip Arden, Amit Arora, Bob Biskner, Kevin 719 Connor, Claus Dahm, Randy Ethier, Roni Even, Jim Frauenthal, Albert 720 Higashi, Tom Hock, Shane Holthaus, Paul Jones, Rajesh Kumar, Keith 721 Lantz, Mohamed Mostafa, Amy Pendleton, Colin Perkins, Mike Ramalho, 722 Ravi Raviraj, Albrecht Schwarz, Tom Taylor, Bill Ver Steeg, David R 723 Oran, Ted Lemon,Benoit Claise, Pete Resnick, Ali Begen and Hideaki 724 Yamada. 726 9. References 728 9.1. Normative References 730 [ATSC] U.S. Advanced Television Systems Committee (ATSC), "ATSC 731 Standard: Digital Audio Compression (AC-3), Revision B", 732 ATSC Doc A/52B, June 2005. 734 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 735 Requirement Levels", BCP 14, RFC 2119, March 1997. 737 [RFC3550] Schulzrinne, H., "RTP: A Transport Protocol for Real-Time 738 Applications", RFC 3550, July 2003. 740 [RFC3551] Schulzrinne, H. and S. Casner, "RTP Profile for Audio and 741 Video Conferences with Minimal Control", RFC 3551, 742 July 2003. 744 [RFC3611] Friedman, T., Caceres, R., and A. Clark, "RTP Control 745 Protocol Extended Reports (RTCP XR)", RFC 3611, 746 November 2003. 748 [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session 749 Description Protocol", RFC 4566, July 2006. 751 [RFC5226] Narten, T., "Guidelines for Writing an IANA Considerations 752 Section in RFCs", RFC 5226, May 2008. 754 [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax 755 Specifications: ABNF", STD 68, RFC 5234, January 2008. 757 [RFC6776] Wu, Q., "Measurement Identity and information Reporting 758 using SDES item and XR Block", RFC 6776, October 2012. 760 9.2. Informative References 762 [BS.1387-1] 763 ITU-R, "Method for objective measurements of perceived 764 audio quality", ITU-R Recommendation BS.1387-1, 2001. 766 [ETSI] ETSI, "Quality of Service (QoS) measurement 767 methodologies", ETSI TS 101 329-5 V1.1.1, November 2000. 769 [G.107] ITU-T, "The E Model, a computational model for use in 770 transmission planning", ITU-T Recommendation G.107, 771 April 2009. 773 [G.107.1] ITU-T, "Wideband E-model", ITU-T Recommendation G.107.1, 774 December 2011. 776 [G.1082] ITU-T, "Measurement-based methods for improving the 777 robustness of IPTV performance", ITU-T 778 Recommendation G.1082, April 2009. 780 [P.1201.1] 781 ITU-T, "Parametric non-intrusive assessment of audiovisual 782 media streaming quality - lower resolution application 783 area", ITU-T Recommendation P.1201.1, October 2012. 785 [P.1201.2] 786 ITU-T, "Parametric non-intrusive assessment of audiovisual 787 media streaming quality - higher resolution application 788 area", ITU-T Recommendation P.1201.2, October 2012. 790 [P.1202.1] 791 ITU-T, "Parametric non-intrusive bitstream assessment of 792 video media streaming quality - lower resolution 793 application area", ITU-T Recommendation P.1202.1, 794 October 2012. 796 [P.1202.2] 797 ITU-T, "Parametric non-intrusive bitstream assessment of 798 video media streaming quality - higher resolution 799 application area", ITU-T Recommendation P.1202.2, 800 May 2013. 802 [P.564] ITU-T, "Conformance testing for narrowband Voice over IP 803 transmission quality assessment models", ITU-T 804 Recommendation P.564, July 2006. 806 [P.862] ITU-T, "Perceptual evaluation of speech quality (PESQ): An 807 objective method for end-to-end speech quality assessment 808 of narrow-band telephone networks and speech codecs", 809 ITU-T Recommendation P.862, Febuary 2001. 811 [P.862.1] ITU-T, "Mapping function for transforming P.862 raw result 812 scores to MOS-LQO", ITU-T Recommendation P.862.1, 813 November 2003. 815 [P.862.2] ITU-T, "Wideband extension to Recommendation P.862 for the 816 assessment of wideband telephone networks and speech 817 codecs", ITU-T Recommendation P.862.2, November 2007. 819 [P.863] ITU-T, "Perceptual objective listening quality 820 assessment", ITU-T Recommendation P.863, January 2011. 822 [RFC4184] Link, B., Hager, T., and J. Flaks, "RTP Payload Format for 823 AC-3 Audio", RFC 4184, October 2005. 825 [RFC4598] Link, B., "Real-time Transport Protocol (RTP) Payload 826 Format for Enhanced AC-3 (E-AC-3) Audio", RFC 4598, 827 July 2006. 829 [RFC5188] Desineni, H. and Q. Xie, "RTP Payload Format for the 830 Enhanced Variable Rate Wideband Codec (EVRC-WB) and the 831 Media Subtype Updates for EVRC-B Codec", RFC 5188, 832 February 2008. 834 [RFC6390] Clark, A. and B. Claise, "Framework for Performance Metric 835 Development", RFC 6390, October 2011. 837 [RFC6792] Wu, Q., "Monitoring Architectures for RTP", RFC 6792, 838 November 2012. 840 [TTC] TTC 201.01 (Japan), "A method for speech quality 841 assessment for Voice over IP". 843 Appendix A. Metrics represented using RFC6390 Template 845 RFC EDITOR NOTE: please change XXXX in [RFCXXXX] by the new RFC 846 number, when assigned. 848 a. MOS Value Metric 850 * Metric Name: MOS in RTP 852 * Metric Description: The estimated Mean Opinion Score for 853 multimedia application performance of RTP stream is defined as 854 including the effects of delay,loss, discard,jitter and other 855 effects that would affect audio or video quality. 857 * Method of Measurement or Calculation: See section 3.2.1, MOS 858 value definition [RFCXXXX]. 860 * Units of Measurement: See section 3.2.1, MOS value definition 861 [RFCXXXX]. 863 * Measurement Point(s) with Potential Measurement Domain: See 864 section 3, 2nd paragraph [RFCXXXX]. 866 * Measurement Timing: See section 3, 3rd paragraph [RFCXXXX] for 867 measurement timing and section 3.1 [RFCXXXX] for Interval 868 Metric flag. 870 * Use and applications: See section 1.4 [RFCXXXX]. 872 * Reporting model: See RFC3611. 874 b. Segment Type Metric 876 * Metric Name: Segment Type in RTP 878 * Metric Description: It is used to identify the segment type of 879 RTP stream used in this report block. For more details, see 880 section 3.2.1, Segment type definition. 882 * Method of Measurement or Calculation: See section 3.2.1, 883 Segment Type definition [RFCXXXX]. 885 * Units of Measurement: See section 3.2.1, Segment Type 886 definition [RFCXXXX]. 888 * Measurement Point(s) with Potential Measurement Domain: See 889 section 3, 2nd paragraph [RFCXXXX]. 891 * Measurement Timing: See section 3, 3rd paragraph [RFCXXXX] for 892 measurement timing and section 3.1 [RFCXXXX] for Interval 893 Metric flag. 895 * Use and applications: See section 1.4 [RFCXXXX]. 897 * Reporting model: See RFC3611. 899 c. Calculation Algorithm Identifier Metric 901 * Metric Name: RTP Stream Calculation Algorithm Identifier 903 * Metric Description: It is the local identifier of RTP Stream 904 calculation Algorithm associated with this segment in the 905 range 1-255 inclusive. 907 * Method of Measurement or Calculation: See section 3.2.1, 908 Calculation Algorithm ID definition [RFCXXXX]. 910 * Units of Measurement: See section 3.2.1, Calg Algorithm ID 911 definition[RFCXXXX]. 913 * Measurement Point(s) with Potential Measurement Domain: See 914 section 3, 2nd paragraph [RFCXXXX]. 916 * Measurement Timing: See section 3, 3rd paragraph [RFCXXXX] for 917 measurement timing and section 3.1 [RFCXXXX] for Interval 918 Metric flag. 920 * Use and applications: See section 1.4 [RFCXXXX]. 922 * Reporting model: See RFC3611. 924 d. Payload Type Metric 926 * Metric Name: RTP Payload Type 928 * Metric Description: It is used to identify the format of the 929 RTP payload. For more details, see section 3.2.1, payload 930 type definition. 932 * Method of Measurement or Calculation: See section 3.2.1, 933 Payload type definition [RFCXXXX]. 935 * Units of Measurement: See section 3.2.1, payload type 936 definition[RFCXXXX]. 938 * Measurement Point(s) with Potential Measurement Domain: See 939 section 3, 2nd paragraph [RFCXXXX]. 941 * Measurement Timing: See section 3, 3rd paragraph [RFCXXXX] for 942 measurement timing and section 3.1 [RFCXXXX] for Interval 943 Metric flag. 945 * Use and applications: See section 1.4 [RFCXXXX]. 947 * Reporting model: See RFC3611. 949 e. Channel Identifier Metric 951 * Metric Name: Audio Channel Identifier in RTP 953 * Metric Description: It is used to identify each audio channel 954 carried in the same RTP stream. For more details, see section 955 3.2.2, channel identifier definition. 957 * Method of Measurement or Calculation: See section 3.2.2, 958 Channel Identifier definition [RFCXXXX]. 960 * Units of Measurement: See section 3.2.2, channel identifier 961 definition[RFCXXXX]. 963 * Measurement Point(s) with Potential Measurement Domain: See 964 section 3, 2nd paragraph [RFCXXXX]. 966 * Measurement Timing: See section 3, 3rd paragraph [RFCXXXX] for 967 measurement timing and section 3.1 [RFCXXXX] for Interval 968 Metric flag. 970 * Use and applications: See section 1.4 [RFCXXXX]. 972 * Reporting model: See RFC3611. 974 Appendix B. Change Log 976 B.1. draft-ietf-xrblock-rtcp-xr-qoe-15 978 The following are the major changes compared to previous version: 979 o Some Editorial Changes. 981 B.2. draft-ietf-xrblock-rtcp-xr-qoe-14 983 The following are the major changes compared to previous version: 984 o Add some texts to address IESG review comments. 986 B.3. draft-ietf-xrblock-rtcp-xr-qoe-10 988 The following are the major changes compared to previous version: 989 o Replace QoE metrics with MoS metrics. 991 B.4. draft-ietf-xrblock-rtcp-xr-qoe-09 993 The following are the major changes compared to previous version: 994 o Address comments recieved from WGLC, PM-DIR Review and SDP review. 995 o Change an existing SDP attribute 'extmap' to new SDP attribute 996 'calgextmap' and add new SDP attribute registry. 997 o Add Reference to G.107.1, P.862.1, P.862.2 and P.863 for new 998 calculation algorithms. 999 o Add MoS type attribute to distinguish different MoS type. 1000 o Other Editorial changes. 1002 B.5. draft-ietf-xrblock-rtcp-xr-qoe-08 1004 The following are the major changes compared to previous version: 1006 o Remove mostype attribute from SDP extension since it can inferred 1007 from payload type. 1008 o Clarify mosref attribute usage in the O/A. 1010 B.6. draft-ietf-xrblock-rtcp-xr-qoe-07 1012 The following are the major changes compared to previous version: 1013 o Some editorial changes to get in line with burst gap related 1014 draft. 1015 o Add an appendix to apply RFC6390 template. 1017 B.7. draft-ietf-xrblock-rtcp-xr-qoe-06 1019 The following are the major changes compared to previous two 1020 versions: 1021 o A few Contact information update. 1022 o A few Acknowledgement section update. 1024 B.8. draft-ietf-xrblock-rtcp-xr-qoe-04 1026 The following are the major changes compared to previous version: 1027 o Split two references P.NAMS and P.NBAMS into four references. 1028 o SDP signaling update. 1029 o Add one example to explain User QoE evaluation for video stream 1031 B.9. draft-ietf-xrblock-rtcp-xr-qoe-03 1033 The following are the major changes compared to previous version: 1034 o Add one new reference to support TTC JJ201.01. 1035 o Update two references P.NAMS and P.NBAMS. 1036 o Other Editorial changes based on comments applied to PDV and Delay 1037 drafts. 1039 B.10. draft-ietf-xrblock-rtcp-xr-qoe-02 1041 The following are the major changes compared to previous version: 1042 o Remove leftmost second bit since it is ueeless. 1043 o Change 13bits MoS value field into 14 bits to increase MoS 1044 precision. 1045 o Fix some typo and make some editorial changes. 1047 B.11. draft-ietf-xrblock-rtcp-xr-qoe-01 1049 The following are the major changes compared to previous version: 1050 o Remove layered support from the QoE Metric draft. 1051 o Allocate 7 bits in the block header for payload type to indicate 1052 what type of payload format is in use and add associated 1053 definition of payload type. 1055 o Clarify using Payload Type to determine the appropriate channel 1056 mapping in the definition of Channel Identifier. 1058 B.12. draft-ietf-xrblock-rtcp-xr-qoe-00 1060 The following are the major changes compared to previous version: 1061 o Allocate one more bit in the single channel per SSC segment to get 1062 alignment with the other two segment type. 1064 Authors' Addresses 1066 Alan Clark 1067 Telchemy Incorporated 1068 2905 Premiere Parkway, Suite 280 1069 Duluth, GA 30097 1070 USA 1072 Email: alan.d.clark@telchemy.com 1074 Qin Wu 1075 Huawei 1076 101 Software Avenue, Yuhua District 1077 Nanjing, Jiangsu 210012 1078 China 1080 Email: sunseawq@huawei.com 1082 Roland Schott 1083 Deutsche Telekom 1084 Heinrich-Hertz-Strasse 3-7 1085 Darmstadt 64295 1086 Germany 1088 Email: Roland.Schott@telekom.de 1089 Glen Zorn 1090 Network Zen 1091 77/440 Soi Phoomjit, Rama IV Road 1092 Phra Khanong, Khlong Toie 1093 Bangkok 10110 1094 Thailand 1096 Phone: +66 (0) 87 502 4274 1097 Email: gwz@net-zen.net