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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references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 4566 (Obsoleted by RFC 8866) == Outdated reference: A later version (-10) exists of draft-ietf-xrblock-rtcp-xr-meas-identity-06 == Outdated reference: A later version (-22) exists of draft-ietf-avtcore-monarch-13 Summary: 1 error (**), 0 flaws (~~), 3 warnings (==), 1 comment (--).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 G. Hunt 3 Internet-Draft Unaffiliated 4 Intended status: Standards Track A. Clark 5 Expires: November 15, 2012 Telchemy 6 K. Gross 7 AVA Networks 8 Q. Wu 9 Huawei 10 May 14, 2012 12 RTCP XR Report Block for Delay metric Reporting 13 draft-ietf-xrblock-rtcp-xr-delay-05.txt 15 Abstract 17 This document defines an RTCP XR Report Block that allows the 18 reporting of Delay metrics for use in a range of RTP 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 November 15, 2012. 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 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 66 5.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 9 67 5.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 9 68 5.3. Contact information for registrations . . . . . . . . . . 9 69 6. Security Considerations . . . . . . . . . . . . . . . . . . . 10 70 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11 71 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 72 8.1. Normative References . . . . . . . . . . . . . . . . . . . 12 73 8.2. Informative References . . . . . . . . . . . . . . . . . . 12 74 Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 13 75 A.1. draft-ietf-xrblock-rtcp-xr-delay-05 . . . . . . . . . . . 13 76 A.2. draft-ietf-xrblock-rtcp-xr-delay-04 . . . . . . . . . . . 13 77 A.3. draft-ietf-xrblock-rtcp-xr-delay-03 . . . . . . . . . . . 13 78 A.4. draft-ietf-xrblock-rtcp-xr-delay-02 . . . . . . . . . . . 13 79 A.5. draft-ietf-xrblock-rtcp-xr-delay-01 . . . . . . . . . . . 13 80 A.6. draft-ietf-xrblock-rtcp-xr-delay-00 . . . . . . . . . . . 14 81 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15 83 1. Introduction 85 1.1. Packet Delay Metrics Block 87 This draft 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 mean, minimum and maximum values of the 90 network round-trip delay between RTP interfaces in peer RTP end 91 systems as measured, for example, using the RTCP method described in 92 [RFC3550]. It also supports reporting of the component of the round- 93 trip delay internal to the local RTP system. 95 The network metrics belong to the class of packet transport delay 96 metrics defined in [MONARCH] (work in progress). 98 1.2. RTCP and RTCP XR Reports 100 The use of RTCP for reporting is defined in [RFC3550]. [RFC3611] 101 defined an extensible structure for reporting using an RTCP Extended 102 Report (XR). This draft defines a new Extended Report block that 103 MUST be used as defined in [RFC3550] and [RFC3611]. 105 1.3. Performance Metrics Framework 107 The Performance Metrics Framework [RFC6390] provides guidance on the 108 definition and specification of performance metrics. Metrics 109 described in this draft either reference external definitions or 110 define metrics generally in accordance with the guidelines in 111 [RFC6390]. 113 1.4. Applicability 115 These metrics are applicable to a range of RTP applications in which 116 this report block would be useful, such as multimedia conferencing 117 and streaming audio and video. 119 2. Terminology 121 2.1. Standards Language 123 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 124 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 125 document are to be interpreted as described in RFC 2119 [RFC2119]. 127 3. Delay Block 129 Metrics in this block report on packet delay in the stream arriving 130 at the RTP system. Instances of this Metrics Block refer by SSRC to 131 the separate auxiliary Measurement Information block [MEASI] which 132 contains measurement intervals. This metric block relies on the 133 measurement interval in the Measurement Information block indicating 134 the span of the report and should be sent in the same compound RTCP 135 packet as the measurement information block. If the measurement 136 interval is not received in the same compound RTCP packet as this 137 metric block, this metric block should be discarded. 139 3.1. Report Block Structure 141 Delay metrics block 143 0 1 2 3 144 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 7 145 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 146 | BT=NDEL | I | resv. | block length = 6 | 147 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 148 | SSRC of Source | 149 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 150 | Mean Network Round Trip Delay | 151 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 152 | Min Network Round Trip Delay | 153 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 154 | Max Network Round Trip Delay | 155 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 156 | End System Delay - Seconds (bit 0-31) | 157 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 158 | End System Delay - Fraction (bit 0-31) | 159 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 161 Figure 1: Report Block Structure 163 3.2. Definition of Fields in Delay Metrics Report Block 165 Block type (BT): 8 bits 167 A Delay Report Block is identified by the constant NDEL. 169 [Note to RFC Editor: please replace NDEL with the IANA provided 170 RTCP XR block type for this block.] 172 Interval Metric flag (I): 2 bit 174 This field is used to indicate whether the Delay metrics are 175 Sampled, Interval or Cumulative metrics, that is, whether the 176 reported values applies to the most recent measurement interval 177 duration between successive metrics reports (I=10) (the Interval 178 Duration) or to the accumulation period characteristic of 179 cumulative measurements (I=11) (the Cumulative Duration) or is a 180 sampled instantaneous value (I=01) (Sampled Value). 182 Reserved (resv): 6 bits 184 These bits are reserved. They MUST be set to zero by senders and 185 SHOULD be ignored by receivers. 187 block length: 16 bits 189 The length of this report block in 32-bit words, minus one. For 190 the Delay block, the block length is equal to 6. 192 SSRC of source: 32 bits 194 As defined in Section 4.1 of [RFC3611]. 196 Mean Network Round Trip Delay: 32 bits 198 The Mean Network Round Trip Delay is the mean value of the RTP-to- 199 RTP interface round trip delay over the measurement period, 200 expressed in units of 1/65536 seconds. This value is typically 201 determined using RTCP SR/RR. 203 If only one measurement of Round Trip Delay is available for the 204 timespan of the report (whether Interval or Cumulative), this 205 single value should be reported as the mean value. 207 If the measurement is unavailable, the value of this field with 208 all bits set to 1 SHOULD be reported. 210 Min Network Round Trip Delay: 32 bits 212 The Min Network Round Trip Delay is the minimum value of the RTP- 213 to-RTP interface round trip delay over the measurement period, 214 expressed in units of 1/65536 seconds. This value is typically 215 determined using RTCP SR/RR. 217 If only one measurement of Round Trip Delay is available for the 218 timespan of the report (whether Interval or Cumulative), this 219 single value should be reported as the minimum value. 221 If the measurement is unavailable, the value of this field with 222 all bits set to 1 SHOULD be reported. 224 Max Network Round Trip Delay: 32 bits 226 The Max Network Round Trip Delay is the maximum value of the RTP- 227 to-RTP interface round trip delay over the measurement period, 228 expressed in units of 1/65536 seconds. This value is typically 229 determined using RTCP SR/RR. 231 If only one measurement of Round Trip Delay is available for the 232 timespan of the report (whether Interval or Cumulative), this 233 single value should be reported as the maximum value. 235 If the measurement is unavailable, the value of this field with 236 all bits set to 1 SHOULD be reported. 238 End System Delay: 64 bits 240 The End System Delay is the internal round trip delay within the 241 reporting endpoint, calculated using the nominal value of the 242 jitter buffer delay plus the accumulation/encoding and decoding/ 243 playout delay associated with the codec being used. The value of 244 this field is represented using a 64-bit NTP-format timestamp as 245 defined in [RFC5905], which is 64-bit unsigned fixed-point number 246 with the integer part in the first 32 bits and the fractional part 247 in the last 32 bits. 249 If the measurement is unavailable, the value of this field with 250 all bits set to 1 SHOULD be reported. 252 4. SDP Signaling 254 [RFC3611] defines the use of SDP (Session Description Protocol) 255 [RFC4566] for signaling the use of XR blocks. XR blocks MAY be used 256 without prior signaling. 258 This section augments the SDP [RFC4566] attribute "rtcp-xr" defined 259 in [RFC3611] by providing an additional value of "xr-format" to 260 signal the use of the report block defined in this document. 262 rtcp-xr-attrib = "a=" "rtcp-xr" ":" [xr-format *(SP xr-format)] CRLF 264 (defined in [RFC3611]) 266 xr-format =/ xr-delay-block 268 xr-delay-block ="delay" 270 5. IANA Considerations 272 New block types for RTCP XR are subject to IANA registration. For 273 general guidelines on IANA considerations for RTCP XR, refer to 274 [RFC3611]. 276 5.1. New RTCP XR Block Type value 278 This document assigns the block type value NDEL in the IANA "RTCP XR 279 Block Type Registry" to the "Delay Metrics Block". 281 [Note to RFC Editor: please replace NDEL with the IANA provided RTCP 282 XR block type for this block.] 284 5.2. New RTCP XR SDP Parameter 286 This document also registers a new parameter "delay" in the "RTCP XR 287 SDP Parameters Registry". 289 5.3. Contact information for registrations 291 The contact information for the registrations is: 293 Geoff Hunt (r.geoff.hunt@gmail.com) 295 Orion 2 PP3, Adastral Park, Martlesham Heath, Ipswich IP5 3RE, United 296 Kingdom 298 6. Security Considerations 300 It is believed that this proposed RTCP XR report block introduces no 301 new security considerations beyond those described in [RFC3611]. 302 This block does not provide per-packet statistics so the risk to 303 confidentiality documented in Section 7, paragraph 3 of [RFC3611] 304 does not apply. 306 7. Acknowledgments 308 The authors gratefully acknowledge the comments and contributions 309 made by Bruce Adams, Philip Arden, Amit Arora, Bob Biskner, Kevin 310 Connor, Claus Dahm, Randy Ethier, Roni Even, Jim Frauenthal, Albert 311 Higashi, Tom Hock, Shane Holthaus, Paul Jones, Rajesh Kumar, Keith 312 Lantz, Mohamed Mostafa, Amy Pendleton, Colin Perkins, Mike Ramalho, 313 Ravi Raviraj, Albrecht Schwarz, Tom Taylor, and Hideaki Yamada. 315 8. References 317 8.1. Normative References 319 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 320 Requirement Levels", March 1997. 322 [RFC3550] Schulzrinne, H., "RTP: A Transport Protocol for Real-Time 323 Applications", RFC 3550, July 2003. 325 [RFC3611] Friedman, T., Caceres, R., and A. Clark, "RTP Control 326 Protocol Extended Reports (RTCP XR)", November 2003. 328 [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session 329 Description Protocol", July 2006. 331 [RFC5905] Mills, D., Martin, J., Burbank, J., and W. Kasch, "Network 332 Time Protocol Version 4: Protocol and Algorithms 333 Specification", RFC 5905, June 2010. 335 8.2. Informative References 337 [MEASI] Hunt, G., "Measurement Identity and information Reporting 338 using SDES item and XR Block", 339 ID draft-ietf-xrblock-rtcp-xr-meas-identity-06, 340 April 2012. 342 [MONARCH] Hunt, G., "Monitoring Architectures for RTP", 343 ID draft-ietf-avtcore-monarch-13, May 2012. 345 [RFC6390] Clark, A. and B. Claise, "Framework for Performance Metric 346 Development", RFC 6390, October 2011. 348 Appendix A. Change Log 350 Note to the RFC-Editor: please remove this section prior to 351 publication as an RFC. 353 A.1. draft-ietf-xrblock-rtcp-xr-delay-05 355 The following are the major changes to previous version : 357 o One typo fixed. 359 A.2. draft-ietf-xrblock-rtcp-xr-delay-04 361 The following are the major changes to previous version : 363 o Revise the definition of sampled metric to get alignment with 364 MONARCH. 366 o Clarify sending the metric block in the same RTCP compound packet 367 as the measurement information block. 369 A.3. draft-ietf-xrblock-rtcp-xr-delay-03 371 The following are the major changes to previous version : 373 o Allocate 64 bit for end system delay and represent it using 64 bit 374 NTP-Timestamp. 376 o Other editorial changes. 378 A.4. draft-ietf-xrblock-rtcp-xr-delay-02 380 The following are the major changes to previous version : 382 o Allocate 32bits for each metrics and change unit for each metric 383 from ms to 1/65536 seconds. 385 A.5. draft-ietf-xrblock-rtcp-xr-delay-01 387 The following are the major changes to previous version : 389 o Updated references. 391 o Allocate one more bit for Interval metric flag to indicate sampled 392 metric can be used. 394 o add a few clarification text for failure mode. 396 A.6. draft-ietf-xrblock-rtcp-xr-delay-00 398 The following are the major changes to previous version : 400 o Changed BNF for SDP following Christian Groves' and Tom Taylor's 401 comments (4th and 5th May 2009). 403 o Updated references. 405 Authors' Addresses 407 Geoff Hunt 408 Unaffiliated 410 Email: r.geoff.hunt@gmail.com 412 Alan Clark 413 Telchemy Incorporated 414 2905 Premiere Parkway, Suite 280 415 Duluth, GA 30097 416 USA 418 Email: alan.d.clark@telchemy.com 420 Kevin Gross 421 AVA Networks 423 Email: kevin.gross@avanw.com 425 Qin Wu 426 Huawei 427 101 Software Avenue, Yuhua District 428 Nanjing, Jiangsu 210012 429 China 431 Email: sunseawq@huawei.com