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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) Summary: 1 error (**), 0 flaws (~~), 1 warning (==), 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 K. Gross 5 Expires: April 11, 2013 AVA Networks 6 Q. Wu 7 Huawei 8 October 8, 2012 10 RTP Control Protocol (RTCP) Extended Report (XR) Block for Delay metric 11 Reporting 12 draft-ietf-xrblock-rtcp-xr-delay-10.txt 14 Abstract 16 This document defines an RTP Control Protocol(RTCP) Extended Report 17 (XR) Block that allows the reporting of Delay metrics for use in a 18 range of Real-time Transport Protocol applications. 20 Status of this Memo 22 This Internet-Draft is submitted in full conformance with the 23 provisions of BCP 78 and BCP 79. 25 Internet-Drafts are working documents of the Internet Engineering 26 Task Force (IETF). Note that other groups may also distribute 27 working documents as Internet-Drafts. The list of current Internet- 28 Drafts is at http://datatracker.ietf.org/drafts/current/. 30 Internet-Drafts are draft documents valid for a maximum of six months 31 and may be updated, replaced, or obsoleted by other documents at any 32 time. It is inappropriate to use Internet-Drafts as reference 33 material or to cite them other than as "work in progress." 35 This Internet-Draft will expire on April 11, 2013. 37 Copyright Notice 39 Copyright (c) 2012 IETF Trust and the persons identified as the 40 document authors. All rights reserved. 42 This document is subject to BCP 78 and the IETF Trust's Legal 43 Provisions Relating to IETF Documents 44 (http://trustee.ietf.org/license-info) in effect on the date of 45 publication of this document. Please review these documents 46 carefully, as they describe your rights and restrictions with respect 47 to this document. Code Components extracted from this document must 48 include Simplified BSD License text as described in Section 4.e of 49 the Trust Legal Provisions and are provided without warranty as 50 described in the Simplified BSD License. 52 Table of Contents 54 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 55 1.1. Packet Delay Metrics Block . . . . . . . . . . . . . . . . 3 56 1.2. RTCP and RTCP XR Reports . . . . . . . . . . . . . . . . . 3 57 1.3. Performance Metrics Framework . . . . . . . . . . . . . . 3 58 1.4. Applicability . . . . . . . . . . . . . . . . . . . . . . 3 59 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 60 2.1. Standards Language . . . . . . . . . . . . . . . . . . . . 4 61 3. Delay Block . . . . . . . . . . . . . . . . . . . . . . . . . 5 62 3.1. Report Block Structure . . . . . . . . . . . . . . . . . . 5 63 3.2. Definition of Fields in Delay Metrics Report Block . . . . 5 64 4. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 8 65 4.1. SDP rtcp-xr-attrib Attribute Extension . . . . . . . . . . 8 66 4.2. Offer/Answer Usage . . . . . . . . . . . . . . . . . . . . 8 67 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 68 5.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 9 69 5.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 9 70 5.3. Contact information for registrations . . . . . . . . . . 9 71 6. Security Considerations . . . . . . . . . . . . . . . . . . . 10 72 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 11 73 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12 74 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 75 9.1. Normative References . . . . . . . . . . . . . . . . . . . 13 76 9.2. Informative References . . . . . . . . . . . . . . . . . . 13 77 Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 14 78 A.1. draft-ietf-xrblock-rtcp-xr-delay-10 . . . . . . . . . . . 14 79 A.2. draft-ietf-xrblock-rtcp-xr-delay-09 . . . . . . . . . . . 14 80 A.3. draft-ietf-xrblock-rtcp-xr-delay-08 . . . . . . . . . . . 14 81 A.4. draft-ietf-xrblock-rtcp-xr-delay-07 . . . . . . . . . . . 14 82 A.5. draft-ietf-xrblock-rtcp-xr-delay-06 . . . . . . . . . . . 14 83 A.6. draft-ietf-xrblock-rtcp-xr-delay-05 . . . . . . . . . . . 14 84 A.7. draft-ietf-xrblock-rtcp-xr-delay-04 . . . . . . . . . . . 15 85 A.8. draft-ietf-xrblock-rtcp-xr-delay-03 . . . . . . . . . . . 15 86 A.9. draft-ietf-xrblock-rtcp-xr-delay-02 . . . . . . . . . . . 15 87 A.10. draft-ietf-xrblock-rtcp-xr-delay-01 . . . . . . . . . . . 15 88 A.11. draft-ietf-xrblock-rtcp-xr-delay-00 . . . . . . . . . . . 15 89 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16 91 1. Introduction 93 1.1. Packet Delay Metrics Block 95 This draft defines a new block type to augment those defined in 96 [RFC3611] for use in a range of RTP applications. The new block type 97 supports the reporting of the mean, minimum and maximum values of the 98 network round-trip delay between RTP interfaces in peer RTP end 99 systems as measured, for example, using the RTCP method described in 100 [RFC3550]. It also supports reporting of the component of the round- 101 trip delay internal to the local RTP system. 103 The network metrics belong to the class of transport metrics defined 104 in [MONARCH]. 106 1.2. RTCP and RTCP XR Reports 108 The use of RTCP for reporting is defined in [RFC3550]. [RFC3611] 109 defined an extensible structure for reporting using an RTCP Extended 110 Report (XR). This draft defines a new Extended Report block for use 111 with[RFC3550] and [RFC3611]. 113 1.3. Performance Metrics Framework 115 The Performance Metrics Framework [RFC6390] provides guidance on the 116 definition and specification of performance metrics. The RTP 117 Monitoring Architectures [MONARCH] provides guideline for reporting 118 block format using RTCP XR. The Metrics Block described in this 119 document are in accordance with the guidelines in [RFC6390] and 120 [MONARCH]. 122 1.4. Applicability 124 These metrics are applicable to a range of RTP applications in which 125 this report block would be useful, such as multimedia conferencing 126 and streaming audio and video. Knowledge of the round-trip delay and 127 delay characteristics can aid other receivers in sizing their receive 128 buffers and selecting a playout delay. The same information is also 129 valuable to network managers in troubleshooting network and user 130 experience issues. 132 2. Terminology 134 2.1. Standards Language 136 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 137 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 138 document are to be interpreted as described in RFC 2119 [RFC2119]. 140 3. Delay Block 142 Metrics in this block report on packet delay in the stream arriving 143 at the RTP system. The measurement of these metrics are made either 144 at the receiving end of the RTP stream or at the sending end of the 145 RTP stream. Instances of this Metrics Block refer by Synchronization 146 source (SSRC) to the separate auxiliary Measurement Information block 147 [MEASI] which contains measurement intervals. This metric block 148 relies on the measurement interval in the Measurement Information 149 block indicating the span of the report and SHOULD be sent in the 150 same compound RTCP packet as the measurement information block. If 151 the measurement interval is not received in the same compound RTCP 152 packet as this metric block, this metric block MUST be discarded. 154 3.1. Report Block Structure 156 Delay metrics block 158 0 1 2 3 159 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 7 160 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 161 | BT=NDEL | I | resv. | block length = 6 | 162 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 163 | SSRC of Source | 164 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 165 | Mean Network Round Trip Delay | 166 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 167 | Min Network Round Trip Delay | 168 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 169 | Max Network Round Trip Delay | 170 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 171 | End System Delay - Seconds (bit 0-31) | 172 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 173 | End System Delay - Fraction (bit 0-31) | 174 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 176 Figure 1: Report Block Structure 178 3.2. Definition of Fields in Delay Metrics Report Block 180 Block type (BT): 8 bits 182 A Delay Report Block is identified by the constant NDEL. 184 [Note to RFC Editor: please replace NDEL with the IANA provided 185 RTCP XR block type for this block.] 187 Interval Metric flag (I): 2 bit 189 This field is used to indicate whether the Delay metrics are 190 Sampled, Interval or Cumulative metrics, that is, whether the 191 reported values applies to the most recent measurement interval 192 duration between successive metrics reports (I=10) (the Interval 193 Duration) or to the accumulation period characteristic of 194 cumulative measurements (I=11) (the Cumulative Duration) or is a 195 sampled instantaneous value (I=01) (Sampled Value). 197 Reserved (resv): 6 bits 199 These bits are reserved. They MUST be set to zero by senders and 200 SHOULD be ignored by receivers. 202 block length: 16 bits 204 The length of this report block in 32-bit words, minus one. For 205 the Delay block, the block length is equal to 6. 207 SSRC of source: 32 bits 209 As defined in Section 4.1 of [RFC3611]. 211 Mean Network Round Trip Delay: 32 bits 213 The Mean Network Round Trip Delay is the mean value of the RTP-to- 214 RTP interface round trip delay over the measurement period, 215 expressed in units of 1/65536 seconds. This value is typically 216 determined using RTCP SR/RR (See RFC 3550 section 6.4.1). It also 217 can be determined using RTCP Receiver Reference Time Report Block 218 and DLRR Report Block (See RFC3611 section 4.5). 220 If only one measurement of Round Trip Delay is available for the 221 timespan of the report (i.e.,the measurement period) (whether 222 Interval or Cumulative), this single value SHOULD be reported as 223 the mean value. 225 If the measurement is unavailable, the value of this field with 226 all bits set to 1 MUST be reported. 228 Min Network Round Trip Delay: 32 bits 230 The Min Network Round Trip Delay is the minimum value of the RTP- 231 to-RTP interface round trip delay over the measurement period, 232 expressed in units of 1/65536 seconds. This value is typically 233 determined using RTCP SR/RR. It also can be determined using RTCP 234 Receiver Reference Time Report Block and DLRR Report Block. 236 If only one measurement of Round Trip Delay is available for the 237 timespan of the report (i.e.,the measurement period) (whether 238 Interval or Cumulative), this single value SHOULD be reported as 239 the minimum value. 241 If the measurement is unavailable, the value of this field with 242 all bits set to 1 MUST be reported. 244 Max Network Round Trip Delay: 32 bits 246 The Max Network Round Trip Delay is the maximum value of the RTP- 247 to-RTP interface round trip delay over the measurement period, 248 expressed in units of 1/65536 seconds. This value is typically 249 determined using RTCP SR/RR. It also can be determined using RTCP 250 Receiver Reference Time Report Block and DLRR Report Block. 252 If only one measurement of Round Trip Delay is available for the 253 timespan of the report (i.e.,the measurement period) (whether 254 Interval or Cumulative), this single value SHOULD be reported as 255 the maximum value. 257 If the measurement is unavailable, the value of this field with 258 all bits set to 1 MUST be reported. 260 End System Delay: 64 bits 262 The End System Delay is the internal round trip delay within the 263 reporting endpoint, calculated using the nominal value of the 264 jitter buffer delay plus the accumulation/encoding and decoding/ 265 playout delay associated with the codec being used. The value of 266 this field is represented using a 64-bit NTP-format timestamp as 267 defined in [RFC5905], which is 64-bit unsigned fixed-point number 268 with the integer part in the first 32 bits and the fractional part 269 in the last 32 bits. 271 If the measurement is unavailable, the value of this field with 272 all bits set to 1 MUST be reported. 274 4. SDP Signaling 276 [RFC3611] defines the use of SDP (Session Description Protocol) 277 [RFC4566] for signaling the use of XR blocks. XR blocks MAY be used 278 without prior signaling. 280 4.1. SDP rtcp-xr-attrib Attribute Extension 282 This section augments the SDP [RFC4566] attribute "rtcp-xr" defined 283 in [RFC3611] by providing an additional value of "xr-format" to 284 signal the use of the report block defined in this document. 286 xr-format =/ xr-delay-block 288 xr-delay-block ="delay" 290 4.2. Offer/Answer Usage 292 When SDP is used in offer-answer context, the SDP Offer/Answer usage 293 defined in [RFC3611] applies. 295 5. IANA Considerations 297 New block types for RTCP XR are subject to IANA registration. For 298 general guidelines on IANA considerations for RTCP XR, refer to 299 [RFC3611]. 301 5.1. New RTCP XR Block Type value 303 This document assigns the block type value NDEL in the IANA "RTCP XR 304 Block Type Registry" to the "Delay Metrics Block". 306 [Note to RFC Editor: please replace NDEL with the IANA provided RTCP 307 XR block type for this block.] 309 5.2. New RTCP XR SDP Parameter 311 This document also registers a new parameter "delay" in the "RTCP XR 312 SDP Parameters Registry". 314 5.3. Contact information for registrations 316 The contact information for the registrations is: 318 Qin Wu (sunseawq@huawei.com) 320 101 Software Avenue, Yuhua District 321 Nanjing, Jiangsu 210012 322 China 324 6. Security Considerations 326 It is believed that this proposed RTCP XR report block introduces no 327 new security considerations beyond those described in [RFC3611]. 328 This block does not provide per-packet statistics, so the risk to 329 confidentiality documented in Section 7, paragraph 3 of [RFC3611] 330 does not apply. 332 7. Contributors 334 Geoff Hunt wrote the initial version of this document. 336 8. Acknowledgments 338 The authors gratefully acknowledge the comments and contributions 339 made by Bruce Adams, Philip Arden, Amit Arora, Bob Biskner, Kevin 340 Connor, Claus Dahm, Randy Ethier, Roni Even, Jim Frauenthal, Albert 341 Higashi, Tom Hock, Shane Holthaus, Paul Jones, Rajesh Kumar, Keith 342 Lantz, Mohamed Mostafa, Amy Pendleton, Colin Perkins, Mike Ramalho, 343 Ravi Raviraj, Albrecht Schwarz, Tom Taylor, and Hideaki Yamada,Jing 344 Zhao,Kevin Gross, Colin Perkins, Charles Eckel, Glen Zorn,Shida 345 Schubert. 347 9. References 349 9.1. Normative References 351 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 352 Requirement Levels", March 1997. 354 [RFC3550] Schulzrinne, H., "RTP: A Transport Protocol for Real-Time 355 Applications", RFC 3550, July 2003. 357 [RFC3611] Friedman, T., Caceres, R., and A. Clark, "RTP Control 358 Protocol Extended Reports (RTCP XR)", November 2003. 360 [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session 361 Description Protocol", July 2006. 363 [RFC5905] Mills, D., Martin, J., Burbank, J., and W. Kasch, "Network 364 Time Protocol Version 4: Protocol and Algorithms 365 Specification", RFC 5905, June 2010. 367 9.2. Informative References 369 [MEASI] Hunt, G., "Measurement Identity and information Reporting 370 using SDES item and XR Block", 371 ID draft-ietf-xrblock-rtcp-xr-meas-identity-10, 372 August 2012. 374 [MONARCH] Hunt, G., "Monitoring Architectures for RTP", 375 ID draft-ietf-avtcore-monarch-22, September 2012. 377 [RFC6390] Clark, A. and B. Claise, "Framework for Performance Metric 378 Development", RFC 6390, October 2011. 380 Appendix A. Change Log 382 Note to the RFC-Editor: please remove this section prior to 383 publication as an RFC. 385 A.1. draft-ietf-xrblock-rtcp-xr-delay-10 387 The following are the major changes to previous version : 389 o Editorial changes based on SDP directorate Review. 391 A.2. draft-ietf-xrblock-rtcp-xr-delay-09 393 The following are the major changes to previous version : 395 o Editorial changes based on comments that are applied to PDV draft. 397 A.3. draft-ietf-xrblock-rtcp-xr-delay-08 399 The following are the major changes to previous version : 401 o Move Geoff Hunt from author list to Contributors section based on 402 his suggestion. 404 A.4. draft-ietf-xrblock-rtcp-xr-delay-07 406 The following are the major changes to previous version : 408 o Editorial changes. 410 o Reference updates. 412 A.5. draft-ietf-xrblock-rtcp-xr-delay-06 414 The following are the major changes to previous version : 416 o Editorial changes. 418 A.6. draft-ietf-xrblock-rtcp-xr-delay-05 420 The following are the major changes to previous version : 422 o One typo fixed. 424 A.7. draft-ietf-xrblock-rtcp-xr-delay-04 426 The following are the major changes to previous version : 428 o Revise the definition of sampled metric to get alignment with 429 MONARCH. 431 o Clarify sending the metric block in the same RTCP compound packet 432 as the measurement information block. 434 A.8. draft-ietf-xrblock-rtcp-xr-delay-03 436 The following are the major changes to previous version : 438 o Allocate 64 bit for end system delay and represent it using 64 bit 439 NTP-Timestamp. 441 o Other editorial changes. 443 A.9. draft-ietf-xrblock-rtcp-xr-delay-02 445 The following are the major changes to previous version : 447 o Allocate 32bits for each metrics and change unit for each metric 448 from ms to 1/65536 seconds. 450 A.10. draft-ietf-xrblock-rtcp-xr-delay-01 452 The following are the major changes to previous version : 454 o Updated references. 456 o Allocate one more bit for Interval metric flag to indicate sampled 457 metric can be used. 459 o add a few clarification text for failure mode. 461 A.11. draft-ietf-xrblock-rtcp-xr-delay-00 463 The following are the major changes to previous version : 465 o Changed BNF for SDP following Christian Groves' and Tom Taylor's 466 comments (4th and 5th May 2009). 468 o Updated references. 470 Authors' Addresses 472 Alan Clark 473 Telchemy Incorporated 474 2905 Premiere Parkway, Suite 280 475 Duluth, GA 30097 476 USA 478 Email: alan.d.clark@telchemy.com 480 Kevin Gross 481 AVA Networks 483 Email: kevin.gross@avanw.com 485 Qin Wu 486 Huawei 487 101 Software Avenue, Yuhua District 488 Nanjing, Jiangsu 210012 489 China 491 Email: sunseawq@huawei.com