idnits 2.17.1 draft-ietf-xrblock-rtcp-xr-burst-gap-discard-08.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 (December 5, 2012) is 4160 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references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 4566 (Obsoleted by RFC 8866) == Outdated reference: A later version (-15) exists of draft-ietf-xrblock-rtcp-xr-discard-09 == Outdated reference: A later version (-11) exists of draft-ietf-xrblock-rtcp-xr-summary-stat-03 Summary: 1 error (**), 0 flaws (~~), 3 warnings (==), 1 comment (--).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 R. Huang 5 Expires: June 8, 2013 Q. Wu, Ed. 6 Huawei 7 December 5, 2012 9 RTP Control Protocol(RTCP) Extended Report (XR) Block for Burst/Gap 10 Discard metric Reporting 11 draft-ietf-xrblock-rtcp-xr-burst-gap-discard-08.txt 13 Abstract 15 This document defines an RTP Control Protocol(RTCP) Extended Report 16 (XR) Block that allows the reporting of Burst and Gap Discard metrics 17 for use in a range of RTP applications. 19 Status of this Memo 21 This Internet-Draft is submitted in full conformance with the 22 provisions of BCP 78 and BCP 79. 24 Internet-Drafts are working documents of the Internet Engineering 25 Task Force (IETF). Note that other groups may also distribute 26 working documents as Internet-Drafts. The list of current Internet- 27 Drafts is at http://datatracker.ietf.org/drafts/current/. 29 Internet-Drafts are draft documents valid for a maximum of six months 30 and may be updated, replaced, or obsoleted by other documents at any 31 time. It is inappropriate to use Internet-Drafts as reference 32 material or to cite them other than as "work in progress." 34 This Internet-Draft will expire on June 8, 2013. 36 Copyright Notice 38 Copyright (c) 2012 IETF Trust and the persons identified as the 39 document authors. All rights reserved. 41 This document is subject to BCP 78 and the IETF Trust's Legal 42 Provisions Relating to IETF Documents 43 (http://trustee.ietf.org/license-info) in effect on the date of 44 publication of this document. Please review these documents 45 carefully, as they describe your rights and restrictions with respect 46 to this document. Code Components extracted from this document must 47 include Simplified BSD License text as described in Section 4.e of 48 the Trust Legal Provisions and are provided without warranty as 49 described in the Simplified BSD License. 51 Table of Contents 53 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 54 1.1. Burst and Gap Discard Report Block . . . . . . . . . . . . 3 55 1.2. RTCP and RTCP XR Reports . . . . . . . . . . . . . . . . . 3 56 1.3. Performance Metrics Framework . . . . . . . . . . . . . . 3 57 1.4. Applicability . . . . . . . . . . . . . . . . . . . . . . 4 58 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 59 2.1. Standards Language . . . . . . . . . . . . . . . . . . . . 5 60 3. Burst/Gap Discard Block . . . . . . . . . . . . . . . . . . . 6 61 3.1. Report Block Structure . . . . . . . . . . . . . . . . . . 6 62 3.2. Definition of Fields in Burst/Gap Discard Report Block . . 6 63 3.3. Derived metrics based on reported metrics . . . . . . . . 8 64 4. Considerations for Voice-over-IP applications . . . . . . . . 9 65 5. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 10 66 5.1. SDP rtcp-xr-attrib Attribute Extension . . . . . . . . . . 10 67 5.2. Offer/Answer Usage . . . . . . . . . . . . . . . . . . . . 10 68 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 69 6.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 11 70 6.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 11 71 6.3. Contact information for registrations . . . . . . . . . . 11 72 7. Security Considerations . . . . . . . . . . . . . . . . . . . 12 73 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 13 74 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14 75 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15 76 10.1. Normative References . . . . . . . . . . . . . . . . . . . 15 77 10.2. Informative References . . . . . . . . . . . . . . . . . . 15 78 Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 16 79 A.1. draft-ietf-xrblock-rtcp-xr-burst-gap-discard-08 . . . . . 16 80 A.2. draft-ietf-xrblock-rtcp-xr-burst-gap-discard-06 . . . . . 16 81 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17 83 1. Introduction 85 1.1. Burst and Gap Discard Report Block 87 This document defines a new block type to augment those defined in 88 [RFC3611] for use in a range of RTP applications. The new block type 89 supports the reporting of the proportion of packets discarded by the 90 receiver due to jitter. The discards during discard bursts are 91 reported, together with the number of bursts. This block is intended 92 to be used in conjunction with [DISCARD] which provides the total 93 packets discarded, and on which this block therefore depends. 94 However the metric in [DISCARD] may be used independently of the 95 metrics in this block. 97 This block provides information on transient IP problems. Burst/Gap 98 metrics are typically used in Cumulative reports however MAY be used 99 in Interval reports. The burstiness of packet discard affects user 100 experience, may influence any sender strategies to mitigate the 101 problem, and may also have diagnostic value. 103 The metric belongs to the class of transport-related end system 104 metrics defined in [RFC6792]. 106 The definitions of Burst, Gap, Loss and Discard are consistent with 107 definitions in [RFC3611]. To accommodate the range of jitter buffer 108 algorithms and packet discard logic that may be used by implementors, 109 the method used to distinguish between bursts and gaps may be an 110 equivalent method to that defined in[RFC3611]. 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 guideline for reporting 124 block format using RTCP XR. The Metrics Block described in this 125 document are in accordance with the guidelines in [RFC6390] and 126 [RFC6792]. 128 1.4. Applicability 130 These metrics are applicable to a range of RTP applications which 131 don't use stream repair means. 133 2. Terminology 135 2.1. Standards Language 137 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 138 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 139 document are to be interpreted as described in RFC 2119 [RFC2119]. 141 In addition, the following terms are defined: 143 Received, Lost and Discarded 145 A packet shall be regarded as lost if it fails to arrive within an 146 implementation-specific time window. A packet that arrives within 147 this time window but is too early or late to be played out or 148 thrown away before playout due to packet duplication or redundancy 149 shall be regarded as discarded. A packet shall be classified as 150 one of received (or OK), discarded or lost. The metric 151 "cumulative number of packets lost" defined in [RFC3550] reports a 152 count of packets lost from the media stream (single SSRC within 153 single RTP session). Similarly the metric "number of packets 154 discarded" defined in [DISCARD] reports a count of packets 155 discarded from the media stream (single SSRC within single RTP 156 session) arriving at the receiver. Another metric defined in 157 [RFC5725] is available to report on packets which are not 158 recovered by any repair techniques which may be in use. 160 Bursts and Gaps 162 The terms Burst and Gap are used in a manner consistent with that 163 of RTCP XR [RFC3611]. RTCP XR views a RTP stream as being divided 164 into bursts, which are periods during which the discard rate is 165 high enough to cause noticeable quality degradation (generally 166 over 5 percent discard rate), and gaps, which are periods during 167 which discarded packets are infrequent and hence quality is 168 generally acceptable. 170 3. Burst/Gap Discard Block 172 Metrics in this block report on Burst/Gap Discard in the stream 173 arriving at the RTP system. The measurement of these metrics are 174 made at the receiving end of the RTP stream. Instances of this 175 Metrics Block refer by Synchronization source (SSRC) to the separate 176 auxiliary Measurement Information block [RFC6776] which contains 177 measurement periods (see RFC6776 section 4.2). This metric block 178 relies on the measurement period in the Measurement Information block 179 indicating the span of the report and SHOULD be sent in the same 180 compound RTCP packet as the measurement information block. If the 181 measurement period is not received in the same compound RTCP packet 182 as this metric block, this metric block MUST be discarded. 184 3.1. Report Block Structure 186 Burst/Gap Discard metrics block 188 0 1 2 3 189 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 1 190 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 191 | BT=NBGD | I | resv. | block length = 3 | 192 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 193 | SSRC of Source | 194 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 195 | Threshold | Packets Discarded in Bursts | 196 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 197 | Total Packets expected in bursts | Reserved. | 198 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 200 Figure 1: Report Block Structure 202 3.2. Definition of Fields in Burst/Gap Discard Report Block 204 Block type (BT): 8 bits 206 A Burst/Gap Discard Report Block is identified by the constant 207 NBGD. 209 [Note to RFC Editor: please replace NBGD with the IANA provided 210 RTCP XR block type for this block.] 212 Interval Metric flag (I): 2 bits 214 This field is used to indicate whether the Burst/Gap Discard 215 metrics are Sampled, Interval or Cumulative metrics: 217 I=10: Interval Duration - the reported value applies to the 218 most recent measurement interval duration between successive 219 metrics reports. 221 I=11: Cumulative Duration - the reported value applies to the 222 accumulation period characteristic of cumulative measurements. 224 I=01: Sampled Value - the reported value is a sampled 225 instantaneous value. 227 In this document, Burst/Gap Discard Metric is not measured at a 228 particular time instant but over one or several reporting 229 intervals. Therefore Burst/Gap Discard Metric MUST NOT be chosen 230 as Sampled Metric. 232 Reserved (resv): 6 bits 234 These bits are reserved. They SHOULD be set to zero by senders 235 and MUST be ignored by receivers. 237 block length: 16 bits 239 The length of this report block in 32-bit words, minus one. For 240 the Burst/Gap discard block, the block length is equal to 3. 242 SSRC of source: 32 bits 244 As defined in Section 4.1 of [RFC3611]. 246 Threshold: 8 bits 248 The Threshold is equivalent to Gmin in [RFC3611], i.e. the number 249 of successive packets that must not be discarded prior to and 250 following a discard packet in order for this discarded packet to 251 be regarded as part of a gap. 253 Packets discarded in bursts: 24 bits 255 The total number of packets discarded during discard bursts. 257 If the measured value exceeds 0xFFFFFD, the value 0xFFFFFE SHOULD 258 be reported to indicate an over-range measurement. If the 259 measurement is unavailable, the value 0xFFFFFF SHOULD be reported. 261 Total packets expected in bursts: 24 bits 263 The total number of packets expected during discarded bursts (that 264 is, the sum of received packets and lost packets). 266 If the measured value exceeds 0xFFFFFD, the value 0xFFFFFE SHOULD 267 be reported to indicate an over-range measurement. If the 268 measurement is unavailable, the value 0xFFFFFF SHOULD be reported. 270 Reserved (resv): 8 bits 272 These bits are reserved. They SHOULD be set to zero by senders 273 and MUST be ignored by receivers. 275 3.3. Derived metrics based on reported metrics 277 The metrics described here are intended to be used in conjunction 278 with information from the Measurement Information block [RFC6776], 279 discard block [DISCARD] (which MUST be present in the same RTCP 280 packet as the Burst/Gap Discard block). 282 These metrics provides the following information relevant to 283 statistical parameters, including: 285 o The fraction of packets discarded during bursts (burst discard 286 rate in [SUMSTAT]) 288 o The fraction of packets discarded during gaps (gap discard rate in 289 [SUMSTAT]) 291 The details on calculation these parameters in the metrics are 292 described in [SUMSTAT]. 294 4. Considerations for Voice-over-IP applications 296 This metric block is applicable to a broad range of RTP applications. 297 Where the metric is used with a Voice-overIP (VoIP) application and 298 the stream repair means is not available, the following 299 considerations apply. 301 RTCP XR views a call as being divided into bursts, which are periods 302 during which the discard rate is high enough to cause noticeable call 303 quality degradation (generally over 5 percent discard rate), and 304 gaps, which are periods during which discarded packets are infrequent 305 and hence call quality is generally acceptable. 307 If Voice Activity Detection is used the Burst and Gap Duration shall 308 be determined as if silence packets had been sent, i.e. a period of 309 silence in excess of Gmin packets MUST terminate a burst condition. 311 The recommended value for the threshold Gmin in [RFC3611] results in 312 a Burst being a period of time during which the call quality is 313 degraded to a similar extent to a typical PCM Severely Errored Second 314 [PSES]. 316 5. SDP Signaling 318 [RFC3611] defines the use of SDP (Session Description Protocol) 319 [RFC4566] for signaling the use of XR blocks. XR blocks MAY be used 320 without prior signaling. 322 5.1. SDP rtcp-xr-attrib Attribute Extension 324 This section augments the SDP [RFC4566] attribute "rtcp-xr" defined 325 in [RFC3611] by providing an additional value of "xr-format" to 326 signal the use of the report block defined in this document. 328 xr-format =/ xr-bgd-block 330 xr-bgd-block = "brst-gap-dscrd" 332 5.2. Offer/Answer Usage 334 When SDP is used in offer-answer context, the SDP Offer/Answer usage 335 defined in [RFC3611] for unilateral "rtcp-xr" attribute parameters 336 applies. For detailed usage in Offer/Answer for unilateral 337 parameter, refer to section 5.2 of [RFC3611]. 339 6. IANA Considerations 341 New block types for RTCP XR are subject to IANA registration. For 342 general guidelines on IANA considerations for RTCP XR, refer to 343 [RFC3611]. 345 6.1. New RTCP XR Block Type value 347 This document assigns the block type value NBGD in the IANA " RTP 348 Control Protocol Extended Reports (RTCP XR) Block Type Registry " to 349 the "Burst/Gap Discard Metrics Block". 351 [Note to RFC Editor: please replace NBGD with the IANA provided RTCP 352 XR block type for this block.] 354 6.2. New RTCP XR SDP Parameter 356 This document also registers a new parameter "brst-gap-dscrd" in the 357 "RTP Control Protocol Extended Reports (RTCP XR) Session Description 358 Protocol (SDP) Parameters Registry". 360 6.3. Contact information for registrations 362 The contact information for the registrations is: 364 Qin Wu (sunseawq@huawei.com) 366 101 Software Avenue, Yuhua District 367 Nanjing, Jiangsu 210012 368 China 370 7. Security Considerations 372 It is believed that this proposed RTCP XR report block introduces no 373 new security considerations beyond those described in [RFC3611]. 374 This block does not provide per-packet statistics so the risk to 375 confidentiality documented in Section 7, paragraph 3 of [RFC3611] 376 does not apply. 378 8. Contributors 380 Geoff Hunt wrote the initial draft of this document. 382 9. Acknowledgments 384 The authors gratefully acknowledge reviews and feedback provided by 385 Bruce Adams, Philip Arden, Amit Arora, Bob Biskner, Kevin Connor, 386 Claus Dahm, Randy Ethier, Roni Even, Jim Frauenthal, Albert Higashi, 387 Tom Hock, Shane Holthaus, Paul Jones, Rajesh Kumar, Keith Lantz, 388 Mohamed Mostafa, Amy Pendleton, Colin Perkins, Mike Ramalho, Ravi 389 Raviraj, Albrecht Schwarz, Tom Taylor, and Hideaki Yamada, Paul 390 Kyzivat. 392 10. References 394 10.1. Normative References 396 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 397 Requirement Levels", March 1997. 399 [RFC3550] Schulzrinne, H., "RTP: A Transport Protocol for Real-Time 400 Applications", RFC 3550, July 2003. 402 [RFC3611] Friedman, T., Caceres, R., and A. Clark, "RTP Control 403 Protocol Extended Reports (RTCP XR)", November 2003. 405 [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session 406 Description Protocol", July 2006. 408 [RFC5725] Begen, A., Hsu, D., and M. Lague, "Post-Repair Loss RLE 409 Report Block Type for RTP Control Protocol (RTCP) Extended 410 Reports (XRs)", RFC 5725, February 2020. 412 10.2. Informative References 414 [DISCARD] Wu, Q., "RTCP XR Report Block for Discard Count metric 415 Reporting", ID draft-ietf-xrblock-rtcp-xr-discard-09, 416 October 2012. 418 [PSES] "URL", http://www.its.bldrdoc.gov/projects/devglossary/ 419 _severely_errored_second.html, October 2011. 421 [RFC6390] Clark, A. and B. Claise, "Framework for Performance Metric 422 Development", RFC 6390, October 2011. 424 [RFC6776] Wu, Q., "Measurement Identity and information Reporting 425 using SDES item and XR Block", RFC 6776, October 2012. 427 [RFC6792] Hunt, G., "Monitoring Architectures for RTP", RFC 6792, 428 November 2012. 430 [SUMSTAT] Zorn, G., "RTCP XR for Summary Statistics Metrics 431 Reporting", ID draft-ietf-xrblock-rtcp-xr-summary-stat-03, 432 November 2012. 434 Appendix A. Change Log 436 Note to the RFC-Editor: please remove this section prior to 437 publication as an RFC. 439 A.1. draft-ietf-xrblock-rtcp-xr-burst-gap-discard-08 441 The following are the major changes compared to previous version: 443 o SDP update based on SDP Directorate Review. 445 o Add some texts to get consistent with RFC6798 and Delay draft. 447 A.2. draft-ietf-xrblock-rtcp-xr-burst-gap-discard-06 449 The following are the major changes compared to previous version: 451 o Outdated reference update. 453 o Editorial changes based on comments that applied to PDV and Delay 454 drafts. 456 Authors' Addresses 458 Alan Clark 459 Telchemy Incorporated 460 2905 Premiere Parkway, Suite 280 461 Duluth, GA 30097 462 USA 464 Email: alan.d.clark@telchemy.com 466 Rachel Huang 467 Huawei Technologies Co., Ltd. 468 101 Software Avenue, Yuhua District 469 Nanjing, Jiangsu 210012 470 China 472 Email: Rachel@huawei.com 474 Qin Wu (editor) 475 Huawei 476 101 Software Avenue, Yuhua District 477 Nanjing, Jiangsu 210012 478 China 480 Email: sunseawq@huawei.com