idnits 2.17.1 draft-ietf-xrblock-rtcp-xr-burst-gap-discard-10.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 (January 17, 2013) is 4116 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: 'RFC6709' is defined on line 442, but no explicit reference was found in the text ** Obsolete normative reference: RFC 4566 (Obsoleted by RFC 8866) == Outdated reference: A later version (-15) exists of draft-ietf-xrblock-rtcp-xr-discard-11 == Outdated reference: A later version (-11) exists of draft-ietf-xrblock-rtcp-xr-summary-stat-05 Summary: 1 error (**), 0 flaws (~~), 4 warnings (==), 1 comment (--).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: July 21, 2013 Q. Wu, Ed. 6 Huawei 7 January 17, 2013 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-10.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 July 21, 2013. 36 Copyright Notice 38 Copyright (c) 2013 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-10 . . . . . 16 80 A.2. draft-ietf-xrblock-rtcp-xr-burst-gap-discard-09 . . . . . 16 81 A.3. draft-ietf-xrblock-rtcp-xr-burst-gap-discard-08 . . . . . 16 82 A.4. draft-ietf-xrblock-rtcp-xr-burst-gap-discard-06 . . . . . 16 83 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17 85 1. Introduction 87 1.1. Burst and Gap Discard Report Block 89 This document 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 discarded by the 92 receiver due to jitter. The discards during discard bursts are 93 reported, together with the number of bursts. This block is intended 94 to be used in conjunction with [DISCARD] which provides the total 95 packets discarded, and on which this block therefore depends. 96 However the metric in [DISCARD] may be used independently of the 97 metrics in this block. 99 This block provides information on transient IP problems. Burst/Gap 100 metrics are typically used in Cumulative reports, however they also 101 MAY be used in Interval reports. The burstiness of packet discard 102 affects user experience, may influence any sender strategies to 103 mitigate the 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]. 114 1.2. RTCP and RTCP XR Reports 116 The use of RTCP for reporting is defined in [RFC3550]. [RFC3611] 117 defined an extensible structure for reporting using an RTCP Extended 118 Report (XR). This document defines a new Extended Report block for 119 use with [RFC3550] and [RFC3611]. 121 1.3. Performance Metrics Framework 123 The Performance Metrics Framework [RFC6390] provides guidance on the 124 definition and specification of performance metrics. The RTP 125 Monitoring Architectures [RFC6792] provides guideline for reporting 126 block format using RTCP XR. The Metrics Block described in this 127 document are in accordance with the guidelines in [RFC6390] and 128 [RFC6792]. 130 1.4. Applicability 132 These metrics are applicable to a range of RTP applications which 133 contain jitter buffers and don't use stream repair means,e.g., 134 Forward Error Correction (FEC) [RFC5109] and/or retransmission 135 [RFC4588]. 137 2. Terminology 139 2.1. Standards Language 141 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 142 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 143 document are to be interpreted as described in RFC 2119 [RFC2119]. 145 In addition, the following terms are defined: 147 Received, Lost and Discarded 149 A packet shall be regarded as lost if it fails to arrive within an 150 implementation-specific time window. A packet that arrives within 151 this time window but is too early or late to be played out or 152 thrown away before playout due to packet duplication or redundancy 153 shall be regarded as discarded. A packet shall be classified as 154 one of received (or OK), discarded or lost. The metric 155 "cumulative number of packets lost" defined in [RFC3550] reports a 156 count of packets lost from the media stream (single SSRC within 157 single RTP session). Similarly the metric "number of packets 158 discarded" defined in [DISCARD] reports a count of packets 159 discarded from the media stream (single SSRC within single RTP 160 session) arriving at the receiver. Another metric defined in 161 [RFC5725] is available to report on packets which are not 162 recovered by any repair techniques which may be in use. 164 Bursts and Gaps 166 The terms Burst and Gap are used in a manner consistent with that 167 of RTCP XR [RFC3611]. RTCP XR views a RTP stream as being divided 168 into bursts, which are periods during which the discard rate is 169 high enough to cause noticeable quality degradation (generally 170 over 5 percent discard rate), and gaps, which are periods during 171 which discarded packets are infrequent and hence quality is 172 generally acceptable. 174 3. Burst/Gap Discard Block 176 Metrics in this block report on Burst/Gap Discard in the stream 177 arriving at the RTP system. The measurement of these metrics are 178 made at the receiving end of the RTP stream. Instances of this 179 Metrics Block refer by Synchronization source (SSRC) to the separate 180 auxiliary Measurement Information block [RFC6776] which describes 181 measurement periods in use (see RFC6776 section 4.2). This Metrics 182 Block relies on the measurement period in the Measurement Information 183 block indicating the span of the report and SHOULD be sent in the 184 same compound RTCP packet as the measurement information block. If 185 the measurement period is not received in the same compound RTCP 186 packet as this Metrics Block, this Metrics Block MUST be discarded. 188 3.1. Report Block Structure 190 Burst/Gap Discard metrics block 192 0 1 2 3 193 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 1 194 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 195 | BT=NBGD | I | resv. | block length = 3 | 196 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 197 | SSRC of Source | 198 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 199 | Threshold | Packets Discarded in Bursts | 200 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 201 | Total Packets expected in bursts | Reserved. | 202 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 204 Figure 1: Report Block Structure 206 3.2. Definition of Fields in Burst/Gap Discard Report Block 208 Block type (BT): 8 bits 210 A Burst/Gap Discard Report Block is identified by the constant 211 NBGD. 213 [Note to RFC Editor: please replace NBGD with the IANA provided 214 RTCP XR block type for this block.] 216 Interval Metric flag (I): 2 bits 218 This field is used to indicate whether the Burst/Gap Discard 219 metrics are Sampled, Interval or Cumulative metrics: 221 I=10: Interval Duration - the reported value applies to the 222 most recent measurement interval duration between successive 223 metrics reports. 225 I=11: Cumulative Duration - the reported value applies to the 226 accumulation period characteristic of cumulative measurements. 228 I=01: Sampled Value - the reported value is a sampled 229 instantaneous value. 231 In this document, Burst/Gap Discard Metrics can only be measured 232 over definite intervals, and cannot be sampled. Accordingly, the 233 value I=01, indicating a sampled value, MUST NOT be used. In 234 addition, the value I=00 is reserved and also MUST NOT be used. 235 The block MUST be discarded if the value I=01 or I=00 is received. 237 Reserved (resv): 6 bits 239 These bits are reserved. They MUST be set to zero by senders and 240 ignored by receivers (See RFC6709 section 4.2). 242 block length: 16 bits 244 The length of this report block in 32-bit words, minus one. For 245 the Burst/Gap discard block, the block length is equal to 3. The 246 block MUST be discarded if the block length is set to a different 247 value. 249 SSRC of source: 32 bits 251 As defined in Section 4.1 of [RFC3611]. 253 Threshold: 8 bits 255 The Threshold is equivalent to Gmin in [RFC3611], i.e. the number 256 of successive packets that must not be discarded prior to and 257 following a discard packet in order for this discarded packet to 258 be regarded as part of a gap. 260 Packets discarded in bursts: 24 bits 262 The total number of packets discarded during discard bursts. 264 If the measured value exceeds 0xFFFFFD, the value 0xFFFFFE MUST be 265 reported to indicate an over-range measurement. If the 266 measurement is unavailable, the value 0xFFFFFF MUST be reported. 268 Total packets expected in bursts: 24 bits 270 The total number of packets expected during discarded bursts (that 271 is, the sum of received packets and lost packets). 273 If the measured value exceeds 0xFFFFFD, the value 0xFFFFFE MUST be 274 reported to indicate an over-range measurement. If the 275 measurement is unavailable, the value 0xFFFFFF MUST be reported. 277 Reserved (resv): 8 bits 279 These bits are reserved. They MUST be set to zero by senders and 280 ignored by receivers (See RFC6709 section 4.2). 282 3.3. Derived metrics based on reported metrics 284 The metrics described here are intended to be used in conjunction 285 with information from the Measurement Information block [RFC6776] 286 (which MUST be present in the same RTCP packet as the Burst/Gap 287 Discard block) and also with the metric "number of packets discarded" 288 provided in the RTCP XR Discard Count Block [DISCARD]. The RTCP XR 289 Discard Count Block SHOULD be sent if the Burst/Gap Discard block is 290 sent, but the converse does not apply. 292 These metrics provide the following information relevant to 293 statistical parameters, including: 295 o The fraction of packets discarded during bursts (burst discard 296 rate in [SUMSTAT]), which can be calculated using the metric " 297 Packets Discarded in Bursts " and the metric " Total Packets 298 expected in Bursts " provided in the Burst/Gap Discard metrics 299 block. 301 o The fraction of packets discarded during gaps (gap discard rate in 302 [SUMSTAT]), which can be calculated using the metric " Packets 303 Discarded in Bursts " and the metric " Total Packets expected in 304 Bursts " provided in the Burst/Gap Discard metrics block. 306 The details on calculation these parameters in the metrics are 307 described in [SUMSTAT]. 309 4. Considerations for Voice-over-IP applications 311 This Metrics Block is applicable to a broad range of RTP 312 applications. Where the metric is used with a Voice-overIP (VoIP) 313 application and the stream repair means is not available, the 314 following considerations apply. 316 RTCP XR views a call as being divided into bursts, which are periods 317 during which the discard rate is high enough to cause noticeable call 318 quality degradation (generally over 5 percent discard rate), and 319 gaps, which are periods during which discarded packets are infrequent 320 and hence call quality is generally acceptable. 322 If Voice Activity Detection is used the Burst and Gap Duration shall 323 be determined as if silence packets had been sent, i.e. a period of 324 silence in excess of Gmin packets MUST terminate a burst condition. 326 The recommended value for the threshold Gmin in [RFC3611] results in 327 a Burst being a period of time during which the call quality is 328 degraded to a similar extent to a typical Pulse-Code Modulation(PCM) 329 Severely Errored Second. 331 5. SDP Signaling 333 [RFC3611] defines the use of SDP (Session Description Protocol) 334 [RFC4566] for signaling the use of XR blocks. XR blocks MAY be used 335 without prior signaling. 337 5.1. SDP rtcp-xr-attrib Attribute Extension 339 This section augments the SDP [RFC4566] attribute "rtcp-xr" defined 340 in [RFC3611] by providing an additional value of "xr-format" to 341 signal the use of the report block defined in this document. 343 xr-format =/ xr-bgd-block 345 xr-bgd-block = "brst-gap-dscrd" 347 5.2. Offer/Answer Usage 349 When SDP is used in offer-answer context, the SDP Offer/Answer usage 350 defined in [RFC3611] for unilateral "rtcp-xr" attribute parameters 351 applies. For detailed usage in Offer/Answer for unilateral 352 parameter, refer to section 5.2 of [RFC3611]. 354 6. IANA Considerations 356 New block types for RTCP XR are subject to IANA registration. For 357 general guidelines on IANA considerations for RTCP XR, refer to 358 [RFC3611]. 360 6.1. New RTCP XR Block Type value 362 This document assigns the block type value NBGD in the IANA " RTP 363 Control Protocol Extended Reports (RTCP XR) Block Type Registry " to 364 the "Burst/Gap Discard Metrics Block". 366 [Note to RFC Editor: please replace NBGD with the IANA provided RTCP 367 XR block type for this block.] 369 6.2. New RTCP XR SDP Parameter 371 This document also registers a new parameter "brst-gap-dscrd" in the 372 "RTP Control Protocol Extended Reports (RTCP XR) Session Description 373 Protocol (SDP) Parameters Registry". 375 6.3. Contact information for registrations 377 The contact information for the registrations is: 379 Qin Wu (sunseawq@huawei.com) 381 101 Software Avenue, Yuhua District 382 Nanjing, Jiangsu 210012 383 China 385 7. Security Considerations 387 It is believed that this proposed RTCP XR report block introduces no 388 new security considerations beyond those described in [RFC3611]. 389 This block does not provide per-packet statistics so the risk to 390 confidentiality documented in Section 7, paragraph 3 of [RFC3611] 391 does not apply. 393 8. Contributors 395 Geoff Hunt wrote the initial draft of this document. 397 9. Acknowledgments 399 The authors gratefully acknowledge reviews and feedback provided by 400 Bruce Adams, Philip Arden, Amit Arora, Bob Biskner, Kevin Connor, 401 Claus Dahm, Randy Ethier, Roni Even, Jim Frauenthal, Albert Higashi, 402 Tom Hock, Shane Holthaus, Paul Jones, Rajesh Kumar, Keith Lantz, 403 Mohamed Mostafa, Amy Pendleton, Colin Perkins, Mike Ramalho, Ravi 404 Raviraj, Albrecht Schwarz, Tom Taylor, Hideaki Yamada, Paul 405 Kyzivat,Claire Bi and Dan Romascanu. 407 10. References 409 10.1. Normative References 411 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 412 Requirement Levels", March 1997. 414 [RFC3550] Schulzrinne, H., "RTP: A Transport Protocol for Real-Time 415 Applications", RFC 3550, July 2003. 417 [RFC3611] Friedman, T., Caceres, R., and A. Clark, "RTP Control 418 Protocol Extended Reports (RTCP XR)", November 2003. 420 [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session 421 Description Protocol", July 2006. 423 [RFC5725] Begen, A., Hsu, D., and M. Lague, "Post-Repair Loss RLE 424 Report Block Type for RTP Control Protocol (RTCP) Extended 425 Reports (XRs)", RFC 5725, February 2020. 427 10.2. Informative References 429 [DISCARD] Wu, Q., "RTCP XR Report Block for Discard Count metric 430 Reporting", ID draft-ietf-xrblock-rtcp-xr-discard-11, 431 December 2012. 433 [RFC4588] Rey, J., Leon, D., , A., Varsa, V., and R. Hakenberg, "RTP 434 Retransmission Payload Format", RFC 4588, July 2006. 436 [RFC5109] Li, A., "RTP Payload Format for Generic Forward Error 437 Correction", RFC 5109, December 2007. 439 [RFC6390] Clark, A. and B. Claise, "Framework for Performance Metric 440 Development", RFC 6390, October 2011. 442 [RFC6709] Carpenter, B., Aboba, B., and S. Cheshire, "Design 443 Considerations for Protocol Extensions", RFC 6709, 444 September 2012. 446 [RFC6776] Wu, Q., "Measurement Identity and information Reporting 447 using SDES item and XR Block", RFC 6776, October 2012. 449 [RFC6792] Hunt, G., "Monitoring Architectures for RTP", RFC 6792, 450 November 2012. 452 [SUMSTAT] Zorn, G., "RTCP XR for Summary Statistics Metrics 453 Reporting", ID draft-ietf-xrblock-rtcp-xr-summary-stat-05, 454 December 2012. 456 Appendix A. Change Log 458 Note to the RFC-Editor: please remove this section prior to 459 publication as an RFC. 461 A.1. draft-ietf-xrblock-rtcp-xr-burst-gap-discard-10 463 The following are the major changes compared to previous version: 465 o Move RFC6709 as one informative reference. 467 A.2. draft-ietf-xrblock-rtcp-xr-burst-gap-discard-09 469 The following are the major changes compared to previous version: 471 o Editorial changes based on comments received in WGLC. 473 A.3. draft-ietf-xrblock-rtcp-xr-burst-gap-discard-08 475 The following are the major changes compared to previous version: 477 o SDP update based on SDP Directorate Review. 479 o Add some texts to get consistent with RFC6798 and Delay draft. 481 A.4. draft-ietf-xrblock-rtcp-xr-burst-gap-discard-06 483 The following are the major changes compared to previous version: 485 o Outdated reference update. 487 o Editorial changes based on comments that applied to PDV and Delay 488 drafts. 490 Authors' Addresses 492 Alan Clark 493 Telchemy Incorporated 494 2905 Premiere Parkway, Suite 280 495 Duluth, GA 30097 496 USA 498 Email: alan.d.clark@telchemy.com 500 Rachel Huang 501 Huawei Technologies Co., Ltd. 502 101 Software Avenue, Yuhua District 503 Nanjing, Jiangsu 210012 504 China 506 Email: Rachel@huawei.com 508 Qin Wu (editor) 509 Huawei 510 101 Software Avenue, Yuhua District 511 Nanjing, Jiangsu 210012 512 China 514 Email: sunseawq@huawei.com