idnits 2.17.1 draft-ietf-xrblock-rtcp-xr-burst-gap-discard-06.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 (October 11, 2012) is 4214 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references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 4566 (Obsoleted by RFC 8866) == Outdated reference: A later version (-15) exists of draft-ietf-xrblock-rtcp-xr-discard-06 Summary: 1 error (**), 0 flaws (~~), 2 warnings (==), 1 comment (--).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 R. Huang 5 Expires: April 14, 2013 Q. Wu, Ed. 6 Huawei 7 October 11, 2012 9 RTP Control Protocol(RTCP) Extended Report (XR) Block for Discard Count 10 metric Reporting 11 draft-ietf-xrblock-rtcp-xr-burst-gap-discard-06.txt 13 Abstract 15 This document defines an RTCP XR Report Block that allows the 16 reporting of Burst and Gap Discard metrics for use in a range of RTP 17 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 April 14, 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 . . . . . . . . . . . . . . . . . . . . . . 3 58 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 59 2.1. Standards Language . . . . . . . . . . . . . . . . . . . . 4 60 3. Burst/Gap Discard Block . . . . . . . . . . . . . . . . . . . 5 61 3.1. Report Block Structure . . . . . . . . . . . . . . . . . . 5 62 3.2. Definition of Fields in Burst/Gap Discard Report Block . . 5 63 3.3. Derived metrics based on reported metrics . . . . . . . . 7 64 4. Considerations for Voice-over-IP applications . . . . . . . . 8 65 5. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 9 66 5.1. SDP rtcp-xr-attrib Attribute Extension . . . . . . . . . . 9 67 5.2. Offer/Answer Usage . . . . . . . . . . . . . . . . . . . . 9 68 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 69 6.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 10 70 6.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 10 71 6.3. Contact information for registrations . . . . . . . . . . 10 72 7. Security Considerations . . . . . . . . . . . . . . . . . . . 11 73 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 12 74 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13 75 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14 76 10.1. Normative References . . . . . . . . . . . . . . . . . . . 14 77 10.2. Informative References . . . . . . . . . . . . . . . . . . 14 78 Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 15 79 A.1. draft-ietf-xrblock-rtcp-xr-burst-gap-discard-06 . . . . . 15 80 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16 82 1. Introduction 84 1.1. Burst and Gap Discard Report Block 86 This document defines a new block type to augment those defined in 87 [RFC3611] for use in a range of RTP applications. The new block type 88 supports the reporting of the proportion of packets discarded by the 89 receiver due to jitter. The discards during discard bursts are 90 reported, together with the number of bursts. This block is intended 91 to be used in conjunction with [DISCARD] which provides the total 92 packets discarded, and on which this block therefore depends. 93 However the metric in [DISCARD] may be used independently of the 94 metrics in this block. 96 This block provides information on transient IP problems. Burst/Gap 97 metrics are typically used in Cumulative reports however MAY be used 98 in Interval reports. The burstiness of packet discard affects user 99 experience, may influence any sender strategies to mitigate the 100 problem, and may also have diagnostic value. 102 The metric belongs to the class of transport-related end system 103 metrics defined in [MONARCH]. 105 The definitions of Burst, Gap, Loss and Discard are consistent with 106 definitions in [RFC3611]. To accommodate the range of jitter buffer 107 algorithms and packet discard logic that may be used by implementors, 108 the method used to distinguish between bursts and gaps may be an 109 equivalent method to that defined in[RFC3611]. 111 1.2. RTCP and RTCP XR Reports 113 The use of RTCP for reporting is defined in [RFC3550]. [RFC3611] 114 defined an extensible structure for reporting using an RTCP Extended 115 Report (XR). This document defines a new Extended Report block for 116 use with [RFC3550] and [RFC3611]. 118 1.3. Performance Metrics Framework 120 The Performance Metrics Framework [RFC6390] provides guidance on the 121 definition and specification of performance metrics. Metrics 122 described in this draft either reference external definitions or 123 define metrics generally in accordance with the guidelines in 124 [RFC6390]. 126 1.4. Applicability 128 These metrics are applicable to a range of RTP applications which 129 don't use stream repair means. 131 2. Terminology 133 2.1. Standards Language 135 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 136 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 137 document are to be interpreted as described in RFC 2119 [RFC2119]. 139 In addition, the following terms are defined: 141 Received, Lost and Discarded 143 A packet shall be regarded as lost if it fails to arrive within an 144 implementation-specific time window. A packet that arrives within 145 this time window but is too early or late to be played out or 146 thrown away before playout due to packet duplication or redundancy 147 shall be regarded as discarded. A packet shall be classified as 148 one of received (or OK), discarded or lost. The metric 149 "cumulative number of packets lost" defined in [RFC3550] reports a 150 count of packets lost from the media stream (single SSRC within 151 single RTP session). Similarly the metric "number of packets 152 discarded" defined in [DISCARD] reports a count of packets 153 discarded from the media stream (single SSRC within single RTP 154 session) arriving at the receiver. Another metric defined in 155 [RFC5725] is available to report on packets which are not 156 recovered by any repair techniques which may be in use. 158 Bursts and Gaps 160 The terms Burst and Gap are used in a manner consistent with that 161 of RTCP XR [RFC3611]. RTCP XR views a RTP stream as being divided 162 into bursts, which are periods during which the discard rate is 163 high enough to cause noticeable quality degradation (generally 164 over 5 percent discard rate), and gaps, which are periods during 165 which discarded packets are infrequent and hence quality is 166 generally acceptable. 168 3. Burst/Gap Discard Block 170 Metrics in this block report on Burst/Gap Discard in the stream 171 arriving at the RTP system. 173 3.1. Report Block Structure 175 Burst/Gap Discard metrics block 177 0 1 2 3 178 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 1 179 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 180 | BT=NBGD | I | resv. | block length = 3 | 181 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 182 | SSRC of Source | 183 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 184 | Threshold | Packets Discarded in Bursts | 185 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 186 | Total Packets expected in bursts | Reserved. | 187 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 189 Figure 1: Report Block Structure 191 3.2. Definition of Fields in Burst/Gap Discard Report Block 193 Block type (BT): 8 bits 195 A Burst/Gap Discard Report Block is identified by the constant 196 NBGD. 198 [Note to RFC Editor: please replace NBGD with the IANA provided 199 RTCP XR block type for this block.] 201 Interval Metric flag (I): 2 bits 203 This field is used to indicate whether the Burst/Gap Discard 204 metrics are Sampled, Interval or Cumulative metrics, that is, 205 whether the reported values applies to the most recent measurement 206 interval duration between successive metrics reports (I=10) (the 207 Interval Duration) or to the accumulation period characteristic of 208 cumulative measurements (I=11) (the Cumulative Duration) or is a 209 sampled instantaneous value (I=01) (Sampled Value). In this 210 document, Burst/Gap Discard Metric is not measured at a particular 211 time instant but over one or several reporting intervals. 212 Therefore Burst/Gap Discard Metric MUST NOT be chosen as Sampled 213 Metric. 215 Reserved (resv): 6 bits 217 These bits are reserved. They SHOULD be set to zero by senders 218 and MUST be ignored by receivers. 220 block length: 16 bits 222 The length of this report block in 32-bit words, minus one. For 223 the Burst/Gap discard block, the block length is equal to 3. 225 SSRC of source: 32 bits 227 As defined in Section 4.1 of [RFC3611]. 229 Threshold: 8 bits 231 The Threshold is equivalent to Gmin in [RFC3611], i.e. the number 232 of successive packets that must not be discarded prior to and 233 following a discard packet in order for this discarded packet to 234 be regarded as part of a gap. 236 Packets discarded in bursts: 24 bits 238 The total number of packets discarded during discard bursts. 240 If the measured value exceeds 0xFFFFFD, the value 0xFFFFFE SHOULD 241 be reported to indicate an over-range measurement. If the 242 measurement is unavailable, the value 0xFFFFFF SHOULD be reported. 244 Total packets expected in bursts: 24 bits 246 The total number of packets expected during discarded bursts (that 247 is, the sum of received packets and lost packets). 249 If the measured value exceeds 0xFFFFFD, the value 0xFFFFFE SHOULD 250 be reported to indicate an over-range measurement. If the 251 measurement is unavailable, the value 0xFFFFFF SHOULD be reported. 253 Reserved (resv): 8 bits 255 These bits are reserved. They SHOULD be set to zero by senders 256 and MUST be ignored by receivers. 258 3.3. Derived metrics based on reported metrics 260 The metrics described here are intended to be used in conjunction 261 with information from the Measurement Information block [MEASID], 262 discard block [DISCARD] (which MUST be present in the same RTCP 263 packet as the Burst/Gap Discard block). 265 These metrics provides the following information relevant to 266 statistical parameters, including: 268 o The fraction of packets discarded during bursts (burst discard 269 rate in [SUMSTAT]) 271 o The fraction of packets discarded during gaps (gap discard rate in 272 [SUMSTAT]) 274 The details on calculation these parameters in the metrics are 275 described in [SUMSTAT]. 277 4. Considerations for Voice-over-IP applications 279 This metric block is applicable to a broad range of RTP applications. 280 Where the metric is used with a Voice-overIP (VoIP) application and 281 the stream repair means is not available, the following 282 considerations apply. 284 RTCP XR views a call as being divided into bursts, which are periods 285 during which the discard rate is high enough to cause noticeable call 286 quality degradation (generally over 5 percent discard rate), and 287 gaps, which are periods during which discarded packets are infrequent 288 and hence call quality is generally acceptable. 290 If Voice Activity Detection is used the Burst and Gap Duration shall 291 be determined as if silence packets had been sent, i.e. a period of 292 silence in excess of Gmin packets MUST terminate a burst condition. 294 The recommended value for the threshold Gmin in [RFC3611] results in 295 a Burst being a period of time during which the call quality is 296 degraded to a similar extent to a typical PCM Severely Errored Second 297 [PSES]. 299 5. SDP Signaling 301 [RFC3611] defines the use of SDP (Session Description Protocol) 302 [RFC4566] for signaling the use of XR blocks. XR blocks MAY be used 303 without prior signaling. 305 5.1. SDP rtcp-xr-attrib Attribute Extension 307 This section augments the SDP [RFC4566] attribute "rtcp-xr" defined 308 in [RFC3611] by providing an additional value of "xr-format" to 309 signal the use of the report block defined in this document. 311 xr-format =/ xr-bgd-block 313 xr-bgd-block = "brst-gap-dscrd" 315 5.2. Offer/Answer Usage 317 When SDP is used in offer-answer context, the SDP Offer/Answer usage 318 defined in [RFC3611] applies. 320 6. IANA Considerations 322 New block types for RTCP XR are subject to IANA registration. For 323 general guidelines on IANA considerations for RTCP XR, refer to 324 [RFC3611]. 326 6.1. New RTCP XR Block Type value 328 This document assigns the block type value NBGD in the IANA "RTCP XR 329 Block Type Registry" to the "Burst/Gap Discard Metrics Block". 331 [Note to RFC Editor: please replace NBGD with the IANA provided RTCP 332 XR block type for this block.] 334 6.2. New RTCP XR SDP Parameter 336 This document also registers a new parameter "brst-gap-dscrd" in the 337 "RTCP XR SDP Parameters Registry". 339 6.3. Contact information for registrations 341 The contact information for the registrations is: 343 Qin Wu (sunseawq@huawei.com) 345 101 Software Avenue, Yuhua District 346 Nanjing, Jiangsu 210012 347 China 349 7. Security Considerations 351 It is believed that this proposed RTCP XR report block introduces no 352 new security considerations beyond those described in [RFC3611]. 353 This block does not provide per-packet statistics so the risk to 354 confidentiality documented in Section 7, paragraph 3 of [RFC3611] 355 does not apply. 357 8. Contributors 359 Geoff Hunt wrote the initial draft of this document. 361 9. Acknowledgments 363 The authors gratefully acknowledge reviews and feedback provided by 364 Bruce Adams, Philip Arden, Amit Arora, Bob Biskner, Kevin Connor, 365 Claus Dahm, Randy Ethier, Roni Even, Jim Frauenthal, Albert Higashi, 366 Tom Hock, Shane Holthaus, Paul Jones, Rajesh Kumar, Keith Lantz, 367 Mohamed Mostafa, Amy Pendleton, Colin Perkins, Mike Ramalho, Ravi 368 Raviraj, Albrecht Schwarz, Tom Taylor, and Hideaki Yamada. 370 10. References 372 10.1. Normative References 374 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 375 Requirement Levels", March 1997. 377 [RFC3550] Schulzrinne, H., "RTP: A Transport Protocol for Real-Time 378 Applications", RFC 3550, July 2003. 380 [RFC3611] Friedman, T., Caceres, R., and A. Clark, "RTP Control 381 Protocol Extended Reports (RTCP XR)", November 2003. 383 [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session 384 Description Protocol", July 2006. 386 [RFC5725] Begen, A., Hsu, D., and M. Lague, "Post-Repair Loss RLE 387 Report Block Type for RTP Control Protocol (RTCP) Extended 388 Reports (XRs)", RFC 5725, February 2020. 390 10.2. Informative References 392 [DISCARD] Hunt, G., "RTCP XR Report Block for Discard Count metric 393 Reporting", ID draft-ietf-xrblock-rtcp-xr-discard-06, 394 October 2012. 396 [MEASID] Wu, Q., "Measurement Identity and information Reporting 397 using SDES item and XR Block", 398 ID draft-ietf-xrblock-rtcp-xr-meas-identity-10, 399 August 2012. 401 [MONARCH] Hunt, G., "Monitoring Architectures for RTP", 402 ID draft-ietf-avtcore-monarch-22, September 2012. 404 [PSES] "URL", http://www.its.bldrdoc.gov/projects/devglossary/ 405 _severely_errored_second.html, October 2011. 407 [RFC6390] Clark, A. and B. Claise, "Framework for Performance Metric 408 Development", RFC 6390, October 2011. 410 [SUMSTAT] Zorn, G., "RTCP XR for Summary Statistics Metrics 411 Reporting", ID draft-zorn-xrblock-rtcp-xr-al-stat-06, 412 July 2012. 414 Appendix A. Change Log 416 Note to the RFC-Editor: please remove this section prior to 417 publication as an RFC. 419 A.1. draft-ietf-xrblock-rtcp-xr-burst-gap-discard-06 421 The following are the major changes compared to previous version: 423 o Outdated reference update. 425 o Editorial changes based on comments that applied to PDV and Delay 426 drafts. 428 Authors' Addresses 430 Alan Clark 431 Telchemy Incorporated 432 2905 Premiere Parkway, Suite 280 433 Duluth, GA 30097 434 USA 436 Email: alan.d.clark@telchemy.com 438 Rachel Huang 439 Huawei Technologies Co., Ltd. 440 101 Software Avenue, Yuhua District 441 Nanjing, Jiangsu 210012 442 China 444 Email: Rachel@huawei.com 446 Qin Wu (editor) 447 Huawei 448 101 Software Avenue, Yuhua District 449 Nanjing, Jiangsu 210012 450 China 452 Email: sunseawq@huawei.com