idnits 2.17.1 draft-ietf-xrblock-rtcp-xr-burst-gap-loss-05.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 date (November 30, 2012) is 4162 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references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 4566 (Obsoleted by RFC 8866) == Outdated reference: A later version (-15) exists of draft-ietf-xrblock-rtcp-xr-discard-06 Summary: 1 error (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Audio/Video Transport Working Group A. Clark 3 Internet-Draft Telchemy 4 Intended status: Standards Track S. Zhang, Ed. 5 Expires: June 3, 2013 J. Zhao 6 STTRI 7 Q. Wu 8 Huawei 9 November 30, 2012 11 RTP Control Protocol (RTCP) Extended Report (XR) Block for Burst/Gap 12 Loss metric Reporting 13 draft-ietf-xrblock-rtcp-xr-burst-gap-loss-05.txt 15 Abstract 17 This document defines an RTP Control Protocol (RTCP) Extended Report 18 (XR) Block that allows the reporting of Burst and Gap Loss metrics 19 for use in a range of RTP applications. 21 Status of this Memo 23 This Internet-Draft is submitted in full conformance with the 24 provisions of BCP 78 and BCP 79. 26 Internet-Drafts are working documents of the Internet Engineering 27 Task Force (IETF). Note that other groups may also distribute 28 working documents as Internet-Drafts. The list of current Internet- 29 Drafts is at http://datatracker.ietf.org/drafts/current/. 31 Internet-Drafts are draft documents valid for a maximum of six months 32 and may be updated, replaced, or obsoleted by other documents at any 33 time. It is inappropriate to use Internet-Drafts as reference 34 material or to cite them other than as "work in progress." 36 This Internet-Draft will expire on June 3, 2013. 38 Copyright Notice 40 Copyright (c) 2012 IETF Trust and the persons identified as the 41 document authors. All rights reserved. 43 This document is subject to BCP 78 and the IETF Trust's Legal 44 Provisions Relating to IETF Documents 45 (http://trustee.ietf.org/license-info) in effect on the date of 46 publication of this document. Please review these documents 47 carefully, as they describe your rights and restrictions with respect 48 to this document. Code Components extracted from this document must 49 include Simplified BSD License text as described in Section 4.e of 50 the Trust Legal Provisions and are provided without warranty as 51 described in the Simplified BSD License. 53 Table of Contents 55 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 56 1.1. Burst and Gap Loss Report Block . . . . . . . . . . . . . 3 57 1.2. RTCP and RTCP XR Reports . . . . . . . . . . . . . . . . . 3 58 1.3. Performance Metrics Framework . . . . . . . . . . . . . . 3 59 1.4. Applicability . . . . . . . . . . . . . . . . . . . . . . 4 60 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 61 2.1. Standards Language . . . . . . . . . . . . . . . . . . . . 5 62 3. Burst/Gap Loss Block . . . . . . . . . . . . . . . . . . . . . 6 63 3.1. Report Block Structure . . . . . . . . . . . . . . . . . . 6 64 3.2. Definition of Fields in Burst/Gap Loss Report Block . . . 6 65 3.3. Derived metrics based on reported metrics . . . . . . . . 9 66 4. Considerations for Voice-over-IP applications . . . . . . . . 10 67 5. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 11 68 5.1. SDP rtcp-xr-attrib Attribute Extension . . . . . . . . . . 11 69 5.2. Offer/Answer Usage . . . . . . . . . . . . . . . . . . . . 11 70 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 71 6.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 12 72 6.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 12 73 6.3. Contact information for registrations . . . . . . . . . . 12 74 7. Security Considerations . . . . . . . . . . . . . . . . . . . 13 75 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 14 76 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 15 77 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16 78 10.1. Normative References . . . . . . . . . . . . . . . . . . . 16 79 10.2. Informative References . . . . . . . . . . . . . . . . . . 16 80 Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 17 81 A.1. draft-ietf-xrblock-rtcp-xr-burst-gap-loss-05 . . . . . . . 17 82 A.2. draft-ietf-xrblock-rtcp-xr-burst-gap-loss-04 . . . . . . . 17 83 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18 85 1. Introduction 87 1.1. Burst and Gap Loss Report Block 89 This draft defines a new block type to augment those defined in 90 [RFC3611] for use in a range of RTP applications. The new block type 91 supports the reporting of the proportion of packets lost by the 92 network. The losses during loss bursts are reported, together with 93 the number of bursts and additional data allowing the calculation of 94 statistical parameters (mean and variance) of the distribution of 95 burst lengths. Some uses of these metrics depend on the availability 96 of the metric "cumulative number of packets lost" from RTCP 97 [RFC3550]. 99 This block provides information on transient IP problems. Burst/Gap 100 metrics are typically used in Cumulative reports however MAY be used 101 in Interval reports. The burstiness of packet loss affects user 102 experience, may influence any sender strategies to mitigate the 103 problem, and may also have diagnostic value. 105 The metric belongs to the class of transport-related end system 106 metrics defined in [RFC6792]. 108 The definitions of Burst, Gap, Loss and Discard are consistent with 109 definitions in [RFC3611]. To accommodate the range of jitter buffer 110 algorithms and packet discard logic that may be used by implementors, 111 the method used to distinguish between bursts and gaps may be an 112 equivalent method to that defined in [RFC3611]. The method used 113 SHOULD produce the same result as that defined in [RFC3611] for 114 conditions of burst packet loss, but MAY produce different results 115 for conditions of time varying jitter. 117 1.2. RTCP and RTCP XR Reports 119 The use of RTCP for reporting is defined in [RFC3550]. [RFC3611] 120 defined an extensible structure for reporting using an RTCP Extended 121 Report (XR). This document defines a new Extended Report block for 122 use with [RFC3550] and [RFC3611]. 124 1.3. Performance Metrics Framework 126 The Performance Metrics Framework [RFC6390] provides guidance on the 127 definition and specification of performance metrics. The RTP 128 Monitoring Architectures [RFC6792] provides guideline for reporting 129 block format using RTCP XR. The Metrics Block described in this 130 document are in accordance with the guidelines in [RFC6390] and 131 [RFC6792]. 133 1.4. Applicability 135 These metrics are applicable to a range of RTP applications which 136 don't use stream repair means. 138 2. Terminology 140 2.1. Standards Language 142 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 143 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 144 document are to be interpreted as described in RFC 2119 [RFC2119]. 146 In addition, the following terms are defined: 148 Received, Lost and Discarded 150 A packet shall be regarded as lost if it fails to arrive within an 151 implementation-specific time window. A packet that arrives within 152 this time window but is too early or late to be played out or 153 thrown away before playout due to packet duplication or redundancy 154 shall be regarded as discarded. A packet shall be classified as 155 one of received (or OK), discarded or lost. The metric 156 "cumulative number of packets lost" defined in [RFC3550] reports a 157 count of packets lost from the media stream (single SSRC within 158 single RTP session). Similarly the metric "number of packets 159 discarded" defined in [DISCARD] reports a count of packets 160 discarded from the media stream (single SSRC within single RTP 161 session) arriving at the receiver. Another metric defined in 162 [RFC5725] is available to report on packets which are not 163 recovered by any repair techniques which may be in use. 165 Bursts and Gaps 167 The terms Burst and Gap are used in a manner consistent with that 168 of RTCP XR [RFC3611]. RTCP XR views a RTP stream as being divided 169 into bursts, which are periods during which the loss rate is high 170 enough to cause noticeable quality degradation (generally over 5 171 percent loss rate), and gaps, which are periods during which lost 172 packets are infrequent and hence quality is generally acceptable. 174 3. Burst/Gap Loss Block 176 Metrics in this block report on Burst/Gap Loss in the stream arriving 177 at the RTP system. 179 3.1. Report Block Structure 181 Burst/Gap Loss metrics block 183 0 1 2 3 184 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 1 185 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 186 | BT=NBGL | I |C| resv. | block length = 5 | 187 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 188 | SSRC of Source | 189 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 190 | Threshold | Sum of Burst Durations (ms) | 191 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 192 | Packets Lost in Bursts | Total... | 193 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 194 | ...Packets expected in bursts | Number of bursts | Sum of| 195 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 196 | ...Squares of Burst Durations (ms-squared) | 197 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 199 Figure 1: Report Block Structure 201 3.2. Definition of Fields in Burst/Gap Loss Report Block 203 Block type (BT): 8 bits 205 A Burst/Gap Loss Report Block is identified by the constant NBGL. 207 [Note to RFC Editor: please replace NBGL with the IANA provided 208 RTCP XR block type for this block.] 210 Interval Metric flag (I): 2 bits 212 This field is used to indicate whether the Burst/Gap Loss metrics 213 are Sampled, Interval or Cumulative metrics: 215 I=10: Interval Duration - the reported value applies to the 216 most recent measurement interval duration between successive 217 metrics reports. 219 I=11: Cumulative Duration - the reported value applies to the 220 accumulation period characteristic of cumulative measurements. 222 I=01: Sampled Value - the reported value is a sampled 223 instantaneous value. 225 In this document, Burst/Gap Loss Metric is not measured at a 226 particular time instant but over one or several reporting 227 intervals. Therefore Burst/Gap Loss Metric MUST NOT be chosen as 228 Sampled Metric. 230 Loss and Discard Combination flag (C): 1 bit 232 The 'C' flag is used to indicate whether combining loss/discard 233 report is needed. This field MUST be set to '1' if the burst gap 234 loss report is present in conjunction with the burst gap discard 235 report in the same compound RTCP packet and MUST be set to '0' 236 otherwise. If the burst gap discard is not sent with the burst 237 gap loss, then the receiver MUST discard the burst gap loss with 238 'C' flag set to 1. If the 'C' flag is set to 0, then receiver 239 MUST NOT discard the burst gap loss metric block when the burst 240 gap discard is not received. 242 Reserved (resv): 5 bits 244 These bits are reserved. They SHOULD be set to zero by senders 245 and MUST be ignored by receivers. 247 block length: 16 bits 249 The length of this report block in 32-bit words, minus one. For 250 the Burst/Gap Loss block, the block length is equal to 5. 252 SSRC of source: 32 bits 254 As defined in Section 4.1 of [RFC3611]. 256 Threshold: 8 bits 258 The Threshold is equivalent to Gmin in [RFC3611], i.e. the number 259 of successive packets that must be received prior to and following 260 a lost packet in order for this lost packet to be regarded as part 261 of a gap. 263 Sum of Burst Durations (ms): 24 bits 265 The total duration of bursts of lost packets in the period of the 266 report (Interval or Cumulative). 268 If the measured value exceeds 0xFFFFFD, the value 0xFFFFFE SHOULD 269 be reported to indicate an over-range measurement. If the 270 measurement is unavailable, the value 0xFFFFFF SHOULD be reported. 272 Packets lost in bursts: 24 bits 274 The total number of packets lost during loss bursts. 276 If the measured value exceeds 0xFFFFFD, the value 0xFFFFFE SHOULD 277 be reported to indicate an over-range measurement. If the 278 measurement is unavailable, the value 0xFFFFFF SHOULD be reported. 280 Total packets expected in bursts: 24 bits 282 The total number of packets expected during loss bursts (that is, 283 the sum of received packets and lost packets). 285 If the measured value exceeds 0xFFFFFD, the value 0xFFFFFE SHOULD 286 be reported to indicate an over-range measurement. If the 287 measurement is unavailable, the value 0xFFFFFF SHOULD be reported. 289 Number of bursts: 16 bits 291 The number of bursts in the period of the report (Interval or 292 Cumulative). 294 If the measured value exceeds 0xFFFD, the value 0xFFFE SHOULD be 295 reported to indicate an over-range measurement. If the 296 measurement is unavailable, the value 0xFFFF SHOULD be reported. 298 Sum of Squares of Burst Durations (ms-squared): 36 bits 300 The sum of the squares of burst durations (where individual burst 301 durations are expressed in ms) over in the period of the report 302 (Interval or Cumulative). The units for this quantity are 303 milliseconds-squared. 305 If the measured value exceeds 0xFFFFFFFFD, the value 0xFFFFFFFFE 306 SHOULD be reported to indicate an over-range measurement. If the 307 measurement is unavailable, the value 0xFFFFFFFFF SHOULD be 308 reported. 310 3.3. Derived metrics based on reported metrics 312 The metrics described here are intended to be used as described in 313 this section, in conjunction with information from the Measurement 314 Information block [RFC6776] (which MUST be present in the same RTCP 315 packet as the Burst/Gap Loss block) and also with the metric 316 "cumulative number of packets lost" provided in standard RTCP 317 [RFC3550]. 319 These metrics provides information relevant to statistical 320 parameters, including: 322 o The fraction of packets lost during bursts (i.e., Burst Loss Rate 323 in [SUMSTAT]) 325 o The fraction of packets lost during gaps (i.e., Gap Loss Rate in 326 [SUMSTAT]) 328 o burst duration mean [SUMSTAT] 330 o burst duration variance [SUMSTAT] 332 The details on calculation these parameters in the metrics are 333 described in [SUMSTAT]. 335 4. Considerations for Voice-over-IP applications 337 This metric block is applicable to a broad range of RTP applications. 338 Where the metric is used with a Voice-overIP (VoIP) application and 339 the stream repair means is not available, the following 340 considerations apply. 342 RTCP XR views a call as being divided into bursts, which are periods 343 during which the loss rate is high enough to cause noticeable call 344 quality degradation (generally over 5 percent loss rate), and gaps, 345 which are periods during which lost packets are infrequent and hence 346 call quality is generally acceptable. 348 If Voice Activity Detection is used the Burst and Gap Duration shall 349 be determined as if silence packets had been sent, i.e. a period of 350 silence in excess of Gmin packets MUST terminate a burst condition. 352 The recommended value for the threshold Gmin in [RFC3611] results in 353 a Burst being a period of time during which the call quality is 354 degraded to a similar extent to a typical PCM Severely Errored Second 355 [PSES]. 357 5. SDP Signaling 359 [RFC3611] defines the use of SDP (Session Description Protocol) 360 [RFC4566] for signaling the use of XR blocks. XR blocks MAY be used 361 without prior signaling. 363 5.1. SDP rtcp-xr-attrib Attribute Extension 365 This section augments the SDP [RFC4566] attribute "rtcp-xr" defined 366 in [RFC3611] by providing an additional value of "xr-format" to 367 signal the use of the report block defined in this document. 369 xr-format =/ xr-bgl-block 371 xr-bgl-block = "brst-gap-loss" 373 5.2. Offer/Answer Usage 375 When SDP is used in offer-answer context, the SDP Offer/Answer usage 376 defined in [RFC3611] for unilateral "rtcp-xr" attribute parameters 377 applies. For detailed usage in Offer/Answer for unilateral 378 parameter, refer to section 5.2 of [RFC3611]. 380 6. IANA Considerations 382 New block types for RTCP XR are subject to IANA registration. For 383 general guidelines on IANA considerations for RTCP XR, refer to 384 [RFC3611]. 386 6.1. New RTCP XR Block Type value 388 This document assigns the block type value NDEL in the IANA "RTCP XR 389 Block Type Registry" to the "Burst/Gap Loss Metrics Block". 391 [Note to RFC Editor: please replace NBGL with the IANA provided RTCP 392 XR block type for this block.] 394 6.2. New RTCP XR SDP Parameter 396 This document also registers a new parameter "brst-gap-loss" in the 397 "RTCP XR SDP Parameters Registry". 399 6.3. Contact information for registrations 401 The contact information for the registrations is: 403 Qin Wu (sunseawq@huawei.com) 405 101 Software Avenue, Yuhua District 406 Nanjing, Jiangsu 210012 407 China 409 7. Security Considerations 411 It is believed that this proposed RTCP XR report block introduces no 412 new security considerations beyond those described in [RFC3611]. 413 This block does not provide per-packet statistics so the risk to 414 confidentiality documented in Section 7, paragraph 3 of [RFC3611] 415 does not apply. 417 8. Contributors 419 Geoff Hunt wrote the initial draft of this document. 421 9. Acknowledgments 423 The authors gratefully acknowledge reviews and feedback provided by 424 Bruce Adams, Philip Arden, Amit Arora, Bob Biskner, Kevin Connor, 425 Claus Dahm, Randy Ethier, Roni Even, Jim Frauenthal, Albert Higashi, 426 Tom Hock, Shane Holthaus, Paul Jones, Rajesh Kumar, Keith Lantz, 427 Mohamed Mostafa, Amy Pendleton, Colin Perkins, Mike Ramalho, Ravi 428 Raviraj, Albrecht Schwarz, Tom Taylor, and Hideaki Yamada. 430 10. References 432 10.1. Normative References 434 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 435 Requirement Levels", March 1997. 437 [RFC3550] Schulzrinne, H., "RTP: A Transport Protocol for Real-Time 438 Applications", RFC 3550, July 2003. 440 [RFC3611] Friedman, T., Caceres, R., and A. Clark, "RTP Control 441 Protocol Extended Reports (RTCP XR)", November 2003. 443 [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session 444 Description Protocol", July 2006. 446 [RFC5725] Begen, A., Hsu, D., and M. Lague, "Post-Repair Loss RLE 447 Report Block Type for RTP Control Protocol (RTCP) Extended 448 Reports (XRs)", RFC 5725, February 2020. 450 10.2. Informative References 452 [DISCARD] Hunt, G., "RTCP XR Report Block for Discard metric 453 Reporting", ID draft-ietf-xrblock-rtcp-xr-discard-06, 454 October 2012. 456 [PSES] "URL", http://www.its.bldrdoc.gov/projects/devglossary/ 457 _severely_errored_second.html, October 2011. 459 [RFC6390] Clark, A. and B. Claise, "Framework for Performance Metric 460 Development", RFC 6390, July 2011. 462 [RFC6776] Wu, Q., "Measurement Identity and information Reporting 463 using SDES item and XR Block", RFC 6776, October 2012. 465 [RFC6792] Hunt, G., "Monitoring Architectures for RTP", RFC 6792, 466 November 2012. 468 [SUMSTAT] Zorn, G., "RTCP XR for Summary Statistics Metrics 469 Reporting", ID draft-zorn-xrblock-rtcp-xr-al-stat-06, 470 July 2012. 472 Appendix A. Change Log 474 Note to the RFC-Editor: please remove this section prior to 475 publication as an RFC. 477 A.1. draft-ietf-xrblock-rtcp-xr-burst-gap-loss-05 479 The following are the major changes compared to previous version: 481 o SDP update based on SDP Directorate Review. 483 A.2. draft-ietf-xrblock-rtcp-xr-burst-gap-loss-04 485 The following are the major changes compared to previous version: 487 o Outdated reference update. 489 o Editorial changes based on comments that applied to PDV and Delay 490 drafts. 492 Authors' Addresses 494 Alan Clark 495 Telchemy Incorporated 496 2905 Premiere Parkway, Suite 280 497 Duluth, GA 30097 498 USA 500 Email: alan.d.clark@telchemy.com 502 Sunshine Zhang (editor) 503 Shanghai Research Institure of China Telecom Corporation Limited 504 No.1835,South Pudong Road 505 Shanghai 200122 506 China 508 Email: zhangyx@sttri.com.cn 510 Jing Zhao 511 Shanghai Research Institure of China Telecom Corporation Limited 512 No.1835,South Pudong Road 513 Shanghai 200122 514 China 516 Email: zhaojing@sttri.com.cn 518 Qin Wu 519 Huawei 520 101 Software Avenue, Yuhua District 521 Nanjing, Jiangsu 210012 522 China 524 Email: sunseawq@huawei.com