idnits 2.17.1 draft-clark-xrblock-rtcp-xr-qoe-00.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year == The document seems to lack the recommended RFC 2119 boilerplate, even if it appears to use RFC 2119 keywords. (The document does seem to have the reference to RFC 2119 which the ID-Checklist requires). -- The document date (November 14, 2011) is 4546 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Unused Reference: '1' is defined on line 364, but no explicit reference was found in the text ** Obsolete normative reference: RFC 4566 (ref. '4') (Obsoleted by RFC 8866) -- Possible downref: Non-RFC (?) normative reference: ref. '5' -- Possible downref: Non-RFC (?) normative reference: ref. '6' -- Possible downref: Non-RFC (?) normative reference: ref. '7' -- Possible downref: Non-RFC (?) normative reference: ref. '8' -- Possible downref: Non-RFC (?) normative reference: ref. '10' Summary: 1 error (**), 0 flaws (~~), 3 warnings (==), 6 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 XRBLOCK Working Group Alan Clark 2 Internet Draft Telchemy 3 Intended status: Standards Track Martin Kastner 4 Expires: May 17, 2012 Telchemy 5 Geoff Hunt 6 Unaffiliated 7 November 14, 2011 9 RTCP XR Report Block for QoE Metrics Reporting 10 draft-clark-xrblock-rtcp-xr-qoe-00 12 Abstract 14 This document defines an RTCP XR Report Block that allows the 15 reporting of QoE metrics for use in voice, audio and video 16 services. 18 Status of this Memo 20 This Internet-Draft is submitted in full conformance with the 21 provisions of BCP 78 and BCP 79. 23 Internet-Drafts are working documents of the Internet Engineering 24 Task Force (IETF). Note that other groups may also distribute 25 working documents as Internet-Drafts. The list of current Internet- 26 Drafts is at http://datatracker.ietf.org/drafts/current/. 28 Internet-Drafts are draft documents valid for a maximum of six months 29 and may be updated, replaced, or obsoleted by other documents at any 30 time. It is inappropriate to use Internet-Drafts as reference 31 material or to cite them other than as "work in progress." 33 This Internet-Draft will expire on May 17, 2012. 35 Copyright Notice 37 Copyright (c) 2011 IETF Trust and the persons identified as the 38 document authors. All rights reserved. 40 This document is subject to BCP 78 and the IETF Trust's Legal 41 Provisions Relating to IETF Documents 42 (http://trustee.ietf.org/license-info) in effect on the date of 43 publication of this document. Please review these documents 44 carefully, as they describe your rights and restrictions with respect 45 to this document. Code Components extracted from this document must 46 include Simplified BSD License text as described in Section 4.e of 47 the Trust Legal Provisions and are provided without warranty as 48 described in the Simplified BSD License. 50 Clark & Kastner [Page 1] 51 RTCP XR QoE Metrics November 2011 53 1. Introduction 55 1.1. QoE Metrics Report Block 57 This draft defines a new block types to augment those defined 58 in RFC3611 for use in reporting QoE metrics. QoE metrics consider 59 the impact of a range of transmission and payload (content) 60 related impairments on the quality of a service from the user 61 viewpoint. 63 1.2. RTCP and RTCP XR Reports 65 The use of RTCP for reporting is defined in RFC3550 [2]. 66 RFC3611 [3] defined an extensible structure for reporting using 67 an RTCP Extended Report (XR). This draft defines 68 a new Extended Report block that MUST be used as defined in 69 RFC3550 and RFC3611. 71 1.3 Performance Metrics Framework 73 The Performance Metrics Framework [9] provides guidance on the 74 definition and specification of performance metrics. Metrics 75 described in this draft either reference external definitions 76 or define metrics generally in accordance with the guidelines 77 in [9]. 79 1.4 Applicability 81 This memo applies to any application of RTP for which QoE 82 measurement algorithms are defined. 84 2. Definitions 86 2.1 QoE Metrics 88 A QoE ("Quality of Experience") metric is intended to provide a 89 measure that is indicative of the user's view of a service. 90 This is commonly expressed as a MOS ("Mean Opinion Score") which 91 usually (but not always) is a 1.0-5.0 numerical scale in which 92 a 1.0 represents "Unacceptable" and 5.0 represents "Excellent". 94 True MOS scores are obtained using subjective testing, and tend 95 vary from test to test. Subjective testing is also not 96 suitable for measuring the quality of operational services and 97 hence it is common practice to use objective algorithms to 98 estimate subjective quality. During the development of such QoE 99 algorithms, there is extensive comparison against both subjective 100 test data and data from other "trusted" objective test tools. 102 Clark & Kastner [Page 2] 103 RTCP XR QoE Metrics November 2011 105 ITU-T Recommendation P.564 defines a methodology for verifying 106 the performance of QoE estimation algorithms for Voice over IP 107 services. There is standardization work underway related to 109 QoE metrics for video and audio. The continuous progression of 110 work in this area means that new algorithms may be defined in 111 the future, hence this memo does make provision for new 112 algorithms. Implementors are advised that IPR disclosures 113 have been made in respect of most known QoE estimation algorithms 114 and they should check the IPR disclosure databases and policies of 115 the relevant standards organizations (for example ITU and ETSI). 117 ITU-T Recommendation P.800.1 describes terminology that should be 118 use for MOS scores used to describe Speech quality. This uses the 119 abbreviations LQ and CQ for Listening and Conversational Quality 120 respectively, and extends these using O for Objective, E for 121 Estimated and S for Subjective. Hence an objectively measured 122 listening quality MOS score would be denoted MOS-LQO. 124 MOS scores typically use a common scale of 1 to 5 and are scaled 125 for comparison with subjectively measured MOS. MOS scores for 126 narrowband speech and wideband speech, or for low resolution 127 video and high resolution video are typically placed into the 128 same range. This occurs because a subjective test is usually 129 a comparitive test amongst similar codecs or devices. Hence a 130 high quality AMR-WB or G.722 wideband voice call may have a lower 131 MOS score than a narrowband G.729 call, even though the quality is 132 higher. Similary, a video subjective test typically uses devices 133 with similar resolution and hence a high definition system may 134 have the same MOS score as a standard definition system. 136 ITU-T P.800.1 addressed this issue of MOS scaling through the use 137 of an additional N or W qualifier to denote Narrowband or Wideband. 138 So a MOS-LQON score is an objectively measured listening quality 139 MOS for narrowband (8kHz sample rate) conditions. Some codecs 140 are able to switch dynamically between narrowband and wideband, 141 which is addressed by the the "M" or mixed qualifier. 143 The issue for audio video MOS is very similar to that of speech. 144 This is addressed by recent work in ITU-T [11] which introduced 145 the idea of Absolute and Relative MOS. Absolute MOS "does" 146 include the effects of image resolution whereas Relative MOS does 147 "not". This draft presumes that ITU-T will adopt similar 148 terminology to P.800.1 for video MOS. [Editors note, will need 149 updating as ITU update relevant standards] 151 Two cases of MOS-CQ have been treated separately in this draft. 152 The first of these is MOS-CQEN, which is an Estimated (not 153 measured) MOS based on ITU-T G.107. The MOS value is calculated 154 by first calculating an R (or RCQ) value and then converting 156 Clark & Kastner [Page 3] 157 RTCP XR QoE Metrics November 2011 159 this to a MOS. This conversion leads to a MOS score that is 160 typically higher than current subjective test data (4.45 vs 161 4.2), which can lead to difficulty interpreting the values. 162 The second case is MOS-CQEN-TTC which is related to a Japanese 163 national standard - TTC JJ201.01. JJ201.01 is based on G.107 164 however Japanese MOS scores are typically much lower than those 165 in other countries and a MOS score for G.711 would be 3.8 in 166 Japan versus 4.2 for a typical subjective test and 4.45 for 167 G.107. 169 It is extremely important that the correct MOS is referenced. 170 For example a MOS of 3.6 would represent a small degree of 171 degration (0.2) using the Japanese JJ201.01 scaling but a very 172 large degradation ( 0.85) using G.107 scaling. 174 2.2 Channel 176 Certain types of encoder (for example stereo audio codecs) 177 incorporate multiple audio or video channels into a single encoded 178 stream which is then packetized and carried in RTP or MPEG 179 Transport. Within the scope of this memo, the term "channel" 180 applies to this definition only - if multiple audio or video 181 streams are carried either in separate RTP sessions (identified 182 by an SSRC) or MPEG Transport program streams (identified by a 183 PID) then the Measurement Identifier block MUST be used to 184 identify the stream to which metrics apply. 186 3. QoE Metrics Block 188 3.1 Report Block Structure 190 0 1 2 3 191 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 192 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 193 | BT=N | I | Tag | block length | 194 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 195 |Chan | Type | Calc alg | QoE Metric | 196 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 197 .......... 198 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 199 |Chan | Type | Calc alg | QoE Metric | 200 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 202 3.2 Definition of Fields in QoE Metric Report Block 204 block type (BT): 8 bits 206 A QoE Report Block is identified by the constant 207 QOEX. 208 [Note to RFC Editor: please replace QOEX with the IANA provided RTCP 209 XR block type for this block.] 211 Clark & Kastner [Page 4] 212 RTCP XR QoE Metrics November 2011 214 Measurement Type Indication (I): 2 bits 216 This field is used to indicate whether the QoE Metrics are 217 Sampled, Interval or Cumulative metrics, that is, whether the 218 reported values applies to the most recent measurement interval 220 duration between successive metrics reports (I=10) (the Interval 221 Duration), to the accumulation period characteristic of 222 cumulative measurements (I=11) (the Cumulative Duration) or is 223 a sampled instantaneous value (I=01). 225 Numerical values for interval or duration are provided in the 226 Measurement Identifier block referenced by the tag field below. 228 Measurement Identifier association (tag): 6 bits 230 This field is used to identify the Measurement Identifier block 231 which describes this measurement. The relevant Measurement 232 Identifier block has the same tag value as the QoE block 233 Note that there may be more than one Measurement Identifier block 234 per RTCP packet. 236 Block length: 16 bits 238 The length of this report block in 32-bit words minus one. 240 Channel 242 The channel number of the audio or video stream to which this 243 metric applies 245 Type 247 0000000 - 0011111 Speech QoE Scores 249 0100000 - 0111111 Audio QoE Scores 251 1000000 - 1011111 Video QoE Scores 253 1100000 - 1111111 Other application QoE Scores 255 Clark & Kastner [Page 5] 256 RTCP XR QoE Metrics November 2011 258 Speech QoE Scores (see ITU-T P.800.1 [10] for definitions) 260 0000000 MOS-LQON - Listening Quality MOS (Narrowband) 261 0000001 MOS-LQOW - Listening Quality MOS (Wideband) 262 0000010 MOS-LQOU - Listening Quality MOS (Ultra wideband) 263 0000011 MOS-LQOM - Listening Quality MOS (Mixed) 264 0000100-0000111 - Reserved 266 0001000 MOS-CQON - Conversational Quality MOS (Narrowband) 267 0001001 MOS-CQOW - Conversational Quality MOS (Wideband) 268 0001010 MOS-CQOU - Conversational Quality MOS (Ultra wideband) 269 0001011 MOS-CQOM - Conversational Quality MOS (Mixed) 270 0001100 MOS-CQEN - Conversational Quality MOS (Narrowband) 271 Scaled per ITU-T G.107 272 0001101 MOS-CQEN-TTC - Conversational Quality MOS (Narrowband) 273 Scaled per TTC JJ201.01 [8] (Japan) 274 0001110-0001111 - Reserved 276 0010000 MOS-TQON - Talking Quality MOS (Narrowband) 277 0010001 MOS-TQOW - Talking Quality MOS (Wideband) 278 0010010 MOS-TQOU - Talking Quality MOS (Ultra wideband) 279 0010011 MOS-TQOM - Talking Quality MOS (Mixed) 280 0010100 - 0010111 - Reserved 282 0011000 R-LQ - R Factor - Listening Quality 283 0011001 R-CQ - R Factor - Conversational Quality [6] 284 0011010 - 0011111 - Reserved 286 Audio QoE Scores (see ITU-T P.??? and [11]) 288 0100000 Absolute MOS-AQOA - Audio Quality MOS, absolute scaling 289 0100001 Relative MOS-AQOR - Audio Quality MOS, relative scaling 291 Video and Multimedia QoE Scores (see ITU-T P.??? and [11]) 293 1000000 Absolute MOS-VQOA - Video Quality MOS, absolute scaling 294 1000001 Relative MOS-VQOR - Video Quality MOS, relative scaling 295 1000100 Absolute MOS-AQOA - Audio-Video Quality MOS, absolute 296 1000101 Relative MOS-AQOR - Audio-Video Quality MOS, relative 298 Other application QoE Scores 300 1100000 - 1111111 Reserved for other interactive applications 301 that use RTP for communication 303 Clark & Kastner [Page 6] 304 RTCP XR QoE Metrics November 2011 306 Calculation Algorithm 308 0 - ITU-T P.564 Compliant Algorithm [5] (Voice) 309 1 - G.107 [6] (Voice) 310 2 - G.107 / ETSI TS 101 329-5 Annex E [6,7] (Voice) 311 3 - TTC JJ201.01 [8] (Japan) 312 4 - Reserved for ITU-T P.NAMS 313 5 - Reserved for ITU-T P.NBAMS 314 255 - Indicated via SDP 316 QoE Metric 318 A 8:8 integer scaled representation of the QoE metric value. 319 This allows values in the range 0.0 to 255.996 to be represented. 321 4. SDP Signaling 323 RFC3611 [3] defines the use of SDP (Session Description Protocol) 324 [4] for signaling the use of XR blocks. XR blocks MAY be used 325 without prior signaling. 327 This section augments the SDP [4] attribute "rtcp-xr" defined in 328 RFC3611[3] by providing a "xr-format" to signal the use of the report 329 block defined in this document. 331 rtcp-xr-attrib = "a=" "rtcp-xr" ":" [xr-format *(SP xr-format)] 332 CRLF (defined in RFC3611) 334 xr-format = xr-format / 335 qoe-metrics 337 qoe-metrics = "qoe-metrics" [EQUAL word] 338 DIGIT = %x30-39 339 format-ext = non-ws-string 340 non-ws-string = 1*(%x21-FF) 341 CRLF = %d13.10 343 5. IANA Considerations 345 This document creates a new block type within the IANA "RTCP XR Block 346 Type Registry" called the QoE Metrics, and a new [new-xrblock] 347 parameter within the "RTCP XR SDP Parameters Registry". 349 Clark & Kastner [Page 7] 350 RTCP XR QoE Metrics November 2011 352 6. Security Considerations 354 RTCP reports can contain sensitive information since they can provide 355 information about the nature and duration of a session established 356 between two or more endpoints. 358 7. Contributors 360 8. References 362 Normative 364 [1] Bradner, S., "Key words for use in RFCs to Indicate 365 Requirement Levels", BCP 14, RFC 2119, March 1997. 367 [2] Schulzrinne, H., Casner, S., Frederick, R. and V. Jacobson, 368 "RTP: A Transport Protocol for Real-Time Applications", STD 64, 369 RFC 3550, July 2003. 371 [3] Friedman, T., Caceres, R., and A. Clark, "RTP Control Protocol 372 Extended Reports (RTCP XR)", RFC 3611, November 2003. 374 [4] Handley, M. and V. Jacobson, "SDP: Session Description 375 Protocol", RFC 4566, July 2006. 377 [5] ITU-T Recommendation P.564, Conformance testing for narrowband 378 Coice over IP transmission quality assessment models 380 [6] ITU-T Recommendation G.107, "The E Model, a computational model 381 for use in transmission planning" 383 [7] ETSI TS 101 329-5, QoS Measurement for Voice over IP 385 [8] TTC 201.01 (Japan) A method for speech quality assessment 386 for Coice over IP 388 [9] Clark A., Claise B. "Guidelines for Considering New Performance 389 Metrics Development", RFC6390, October 2011 391 [10] ITU-T P.800.1 "Mean Opinion Score (MOS) terminology" 393 Informative 395 [11] ITU-T TD483 "Interpretation of MOS in different contexts", 396 January 2011 398 Clark & Kastner [Page 8] 399 RTCP XR QoE Metrics November 2011 401 Author's Addresses 403 Alan Clark 404 Telchemy Incorporated 405 2905 Premiere Parkway, Suite 280 406 Duluth, GA 30097 407 USA 409 Email: alan.d.clark@telchemy.com 411 Martin Kastner 412 Telchemy Incorporated 413 2905 Premiere Parkway, Suite 280 414 Duluth, GA 30097 415 USA 417 Email: martin.kastner@telchemy.com 419 Geoff Hunt 420 Unaffiliated 422 Clark & Kastner [Page 9]