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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references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 4566 (Obsoleted by RFC 8866) == Outdated reference: A later version (-10) exists of draft-ietf-xrblock-rtcp-xr-meas-identity-06 == Outdated reference: A later version (-22) exists of draft-ietf-avtcore-monarch-12 Summary: 1 error (**), 0 flaws (~~), 3 warnings (==), 1 comment (--).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: October 23, 2012 Telchemy 6 K. Gross 7 AVA Networks 8 Q. Wu 9 Huawei 10 April 21, 2012 12 RTCP XR Report Block for Delay metric Reporting 13 draft-ietf-xrblock-rtcp-xr-delay-03.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 October 23, 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-03 . . . . . . . . . . . 13 76 A.2. draft-ietf-xrblock-rtcp-xr-delay-02 . . . . . . . . . . . 13 77 A.3. draft-ietf-xrblock-rtcp-xr-delay-01 . . . . . . . . . . . 13 78 A.4. draft-ietf-xrblock-rtcp-xr-delay-00 . . . . . . . . . . . 13 79 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14 81 1. Introduction 83 1.1. Packet Delay Metrics Block 85 This draft defines a new block type to augment those defined in 86 [RFC3611] for use in a range of RTP applications. The new block type 87 supports the reporting of the mean, minimum and maximum values of the 88 network round-trip delay between RTP interfaces in peer RTP end 89 systems as measured, for example, using the RTCP method described in 90 [RFC3550]. It also supports reporting of the component of the round- 91 trip delay internal to the local RTP system. 93 The network metrics belong to the class of packet transport delay 94 metrics defined in [MONARCH] (work in progress). 96 1.2. RTCP and RTCP XR Reports 98 The use of RTCP for reporting is defined in [RFC3550]. [RFC3611] 99 defined an extensible structure for reporting using an RTCP Extended 100 Report (XR). This draft defines a new Extended Report block that 101 MUST be used as defined in [RFC3550] and [RFC3611]. 103 1.3. Performance Metrics Framework 105 The Performance Metrics Framework [RFC6390] provides guidance on the 106 definition and specification of performance metrics. Metrics 107 described in this draft either reference external definitions or 108 define metrics generally in accordance with the guidelines in 109 [RFC6390]. 111 1.4. Applicability 113 These metrics are applicable to a range of RTP applications in which 114 this report block would be useful, such as multimedia conferencing 115 and streaming audio and video. 117 2. Terminology 119 2.1. Standards Language 121 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 122 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 123 document are to be interpreted as described in RFC 2119 [RFC2119]. 125 3. Delay Block 127 Metrics in this block report on packet delay in the stream arriving 128 at the RTP system. Instances of this Metrics Block refer by SSRC to 129 the separate auxiliary Measurement Information block [MEASI] which 130 contains measurement intervals. This metric block relies on the 131 measurement interval in the Measurement Information block indicating 132 the span of the report. If the measurement interval is not received 133 in the same compound RTCP packet as this metric block, this metric 134 block should be discarded. 136 3.1. Report Block Structure 138 Delay metrics block 140 0 1 2 3 141 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 7 142 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 143 | BT=NDEL | I | resv. | block length = 6 | 144 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 145 | SSRC of Source | 146 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 147 | Mean Network Round Trip Delay | 148 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 149 | Min Network Round Trip Delay | 150 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 151 | Max Network Round Trip Delay | 152 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 153 | End System Delay - Seconds (bit 0-31) | 154 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 155 | End System Delay - Fraction (bit 0-31) | 156 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 158 Figure 1: Report Block Structure 160 3.2. Definition of Fields in Delay Metrics Report Block 162 Block type (BT): 8 bits 164 A Delay Report Block is identified by the constant NDEL. 166 [Note to RFC Editor: please replace NDEL with the IANA provided 167 RTCP XR block type for this block.] 169 Interval Metric flag (I): 2 bit 171 This field is used to indicate whether the Delay metrics are 172 Sampled, Interval or Cumulative metrics, that is, whether the 173 reported values applies to the most recent measurement interval 174 duration between successive metrics reports (I=10) (the Interval 175 Duration) or to the accumulation period characteristic of 176 cumulative measurements (I=11) (the Cumulative Duration) or to the 177 value of a continuously measured or calculated that has been 178 sampled at end of the interval (I=01) (Sampled Value). 180 Reserved (resv): 6 bits 182 These bits are reserved. They MUST be set to zero by senders and 183 SHOULD be ignored by receivers. 185 block length: 16 bits 187 The length of this report block in 32-bit words, minus one. For 188 the Delay block, the block length is equal to 6. 190 SSRC of source: 32 bits 192 As defined in Section 4.1 of [RFC3611]. 194 Mean Network Round Trip Delay: 32 bits 196 The Mean Network Round Trip Delay is the mean value of the RTP-to- 197 RTP interface round trip delay over the measurement period, 198 expressed in units of 1/65536 seconds. This value is typically 199 determined using RTCP SR/RR. 201 If only one measurement of Round Trip Delay is available for the 202 timespan of the report (whether Interval or Cumulative), this 203 single value should be reported as the mean value. 205 If the measurement is unavailable, the value 0xFFFFFFFF SHOULD be 206 reported. 208 Min Network Round Trip Delay: 32 bits 210 The Min Network Round Trip Delay is the minimum value of the RTP- 211 to-RTP interface round trip delay over the measurement period, 212 expressed in units of 1/65536 seconds. This value is typically 213 determined using RTCP SR/RR. 215 If only one measurement of Round Trip Delay is available for the 216 timespan of the report (whether Interval or Cumulative), this 217 single value should be reported as the minimum value. 219 If the measurement is unavailable, the value 0xFFFFFFFF SHOULD be 220 reported. 222 Max Network Round Trip Delay: 32 bits 224 The Max Network Round Trip Delay is the maximum value of the RTP- 225 to-RTP interface round trip delay over the measurement period, 226 expressed in units of 1/65536 seconds. This value is typically 227 determined using RTCP SR/RR. 229 If only one measurement of Round Trip Delay is available for the 230 timespan of the report (whether Interval or Cumulative), this 231 single value should be reported as the maximum value. 233 If the measurement is unavailable, the value 0xFFFFFFFF SHOULD be 234 reported. 236 End System Delay: 64 bits 238 The End System Delay is the internal round trip delay within the 239 reporting endpoint, calculated using the nominal value of the 240 jitter buffer delay plus the accumulation/encoding and decoding/ 241 playout delay associated with the codec being used. The value of 242 this field is represented using a 64-bit NTP-format timestamp as 243 defined in [RFC5905], which is 64-bit unsigned fixed-point number 244 with the integer part in the first 32 bits and the fractional part 245 in the last 32 bits. 247 If the measurement is unavailable, the value 0xFFFFFFFF SHOULD be 248 reported. 250 4. SDP Signaling 252 [RFC3611] defines the use of SDP (Session Description Protocol) 253 [RFC4566] for signaling the use of XR blocks. XR blocks MAY be used 254 without prior signaling. 256 This section augments the SDP [RFC4566] attribute "rtcp-xr" defined 257 in [RFC3611] by providing an additional value of "xr-format" to 258 signal the use of the report block defined in this document. 260 rtcp-xr-attrib = "a=" "rtcp-xr" ":" [xr-format *(SP xr-format)] CRLF 262 (defined in [RFC3611]) 264 xr-format =/ xr-delay-block 266 xr-delay-block ="delay" 268 5. IANA Considerations 270 New block types for RTCP XR are subject to IANA registration. For 271 general guidelines on IANA considerations for RTCP XR, refer to 272 [RFC3611]. 274 5.1. New RTCP XR Block Type value 276 This document assigns the block type value NDEL in the IANA "RTCP XR 277 Block Type Registry" to the "Delay Metrics Block". 279 [Note to RFC Editor: please replace NDEL with the IANA provided RTCP 280 XR block type for this block.] 282 5.2. New RTCP XR SDP Parameter 284 This document also registers a new parameter "delay" in the "RTCP XR 285 SDP Parameters Registry". 287 5.3. Contact information for registrations 289 The contact information for the registrations is: 291 Geoff Hunt (r.geoff.hunt@gmail.com) 293 Orion 2 PP3, Adastral Park, Martlesham Heath, Ipswich IP5 3RE, United 294 Kingdom 296 6. Security Considerations 298 It is believed that this proposed RTCP XR report block introduces no 299 new security considerations beyond those described in [RFC3611]. 300 This block does not provide per-packet statistics so the risk to 301 confidentiality documented in Section 7, paragraph 3 of [RFC3611] 302 does not apply. 304 7. Acknowledgments 306 The authors gratefully acknowledge the comments and contributions 307 made by Bruce Adams, Philip Arden, Amit Arora, Bob Biskner, Kevin 308 Connor, Claus Dahm, Randy Ethier, Roni Even, Jim Frauenthal, Albert 309 Higashi, Tom Hock, Shane Holthaus, Paul Jones, Rajesh Kumar, Keith 310 Lantz, Mohamed Mostafa, Amy Pendleton, Colin Perkins, Mike Ramalho, 311 Ravi Raviraj, Albrecht Schwarz, Tom Taylor, and Hideaki Yamada. 313 8. References 315 8.1. Normative References 317 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 318 Requirement Levels", March 1997. 320 [RFC3550] Schulzrinne, H., "RTP: A Transport Protocol for Real-Time 321 Applications", RFC 3550, July 2003. 323 [RFC3611] Friedman, T., Caceres, R., and A. Clark, "RTP Control 324 Protocol Extended Reports (RTCP XR)", November 2003. 326 [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session 327 Description Protocol", July 2006. 329 [RFC5905] Mills, D., Martin, J., Burbank, J., and W. Kasch, "Network 330 Time Protocol Version 4: Protocol and Algorithms 331 Specification", RFC 5905, June 2010. 333 8.2. Informative References 335 [MEASI] Hunt, G., "Measurement Identity and information Reporting 336 using SDES item and XR Block", 337 ID draft-ietf-xrblock-rtcp-xr-meas-identity-06, 338 April 2012. 340 [MONARCH] Hunt, G., "Monitoring Architectures for RTP", 341 ID draft-ietf-avtcore-monarch-12, April 2012. 343 [RFC6390] Clark, A. and B. Claise, "Framework for Performance Metric 344 Development", RFC 6390, October 2011. 346 Appendix A. Change Log 348 Note to the RFC-Editor: please remove this section prior to 349 publication as an RFC. 351 A.1. draft-ietf-xrblock-rtcp-xr-delay-03 353 The following are the major changes to previous version : 355 o Allocate 64 bit for end system delay and represent it using 64 bit 356 NTP-Timestamp. 358 o Other editorial changes. 360 A.2. draft-ietf-xrblock-rtcp-xr-delay-02 362 The following are the major changes to previous version : 364 o Allocate 32bits for each metrics and change unit for each metric 365 from ms to 1/65536 seconds. 367 A.3. draft-ietf-xrblock-rtcp-xr-delay-01 369 The following are the major changes to previous version : 371 o Updated references. 373 o Allocate one more bit for Interval metric flag to indicate sampled 374 metric can be used. 376 o add a few clarification text for failure mode. 378 A.4. draft-ietf-xrblock-rtcp-xr-delay-00 380 The following are the major changes to previous version : 382 o Changed BNF for SDP following Christian Groves' and Tom Taylor's 383 comments (4th and 5th May 2009). 385 o Updated references. 387 Authors' Addresses 389 Geoff Hunt 390 Unaffiliated 392 Email: r.geoff.hunt@gmail.com 394 Alan Clark 395 Telchemy Incorporated 396 2905 Premiere Parkway, Suite 280 397 Duluth, GA 30097 398 USA 400 Email: alan.d.clark@telchemy.com 402 Kevin Gross 403 AVA Networks 405 Email: kevin.gross@avanw.com 407 Qin Wu 408 Huawei 409 101 Software Avenue, Yuhua District 410 Nanjing, Jiangsu 210012 411 China 413 Email: sunseawq@huawei.com