idnits 2.17.1 draft-ietf-xrblock-rtcp-xr-delay-12.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 (November 19, 2012) is 4174 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 370, but no explicit reference was found in the text ** Obsolete normative reference: RFC 4566 (Obsoleted by RFC 8866) ** Downref: Normative reference to an Informational RFC: RFC 6709 Summary: 2 errors (**), 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 K. Gross 5 Expires: May 23, 2013 AVA Networks 6 Q. Wu 7 Huawei 8 November 19, 2012 10 RTP Control Protocol (RTCP) Extended Report (XR) Block for Delay metric 11 Reporting 12 draft-ietf-xrblock-rtcp-xr-delay-12.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 May 23, 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 . . . . . . . . . . . . . . . . . . . . . . . . 9 65 4.1. SDP rtcp-xr-attrib Attribute Extension . . . . . . . . . . 9 66 4.2. Offer/Answer Usage . . . . . . . . . . . . . . . . . . . . 9 67 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 68 5.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 10 69 5.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 10 70 5.3. Contact information for registrations . . . . . . . . . . 10 71 6. Security Considerations . . . . . . . . . . . . . . . . . . . 11 72 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 12 73 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13 74 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14 75 9.1. Normative References . . . . . . . . . . . . . . . . . . . 14 76 9.2. Informative References . . . . . . . . . . . . . . . . . . 14 77 Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 15 78 A.1. draft-ietf-xrblock-rtcp-xr-delay-12 . . . . . . . . . . . 15 79 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16 81 1. Introduction 83 1.1. Packet Delay Metrics Block 85 This document 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 transport metrics defined 94 in [MONARCH]. 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 document defines a new Extended Report block for 101 use with[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. The RTP 107 Monitoring Architectures [MONARCH] provides guideline for reporting 108 block format using RTCP XR. The Metrics Block described in this 109 document are in accordance with the guidelines in [RFC6390] and 110 [MONARCH]. 112 1.4. Applicability 114 These metrics are applicable to a range of RTP applications in which 115 this report block would be useful, such as multimedia conferencing 116 and streaming audio and video. Knowledge of the round-trip delay and 117 delay characteristics can aid other receivers in sizing their receive 118 buffers and selecting a playout delay. The same information is also 119 valuable to network managers in troubleshooting network and user 120 experience issues. 122 2. Terminology 124 2.1. Standards Language 126 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 127 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 128 document are to be interpreted as described in RFC 2119 [RFC2119]. 130 3. Delay Block 132 Metrics in this block report on packet delay in the stream arriving 133 at the RTP system. The measurement of these metrics are made either 134 at the receiving end of the RTP stream or at the sending end of the 135 RTP stream. Instances of this Metrics Block refer by Synchronization 136 source (SSRC) to the separate auxiliary Measurement Information block 137 [RFC6776] which contains measurement periods (see RFC6776 section 138 4.2). This metric block relies on the measurement period in the 139 Measurement Information block indicating the span of the report and 140 SHOULD be sent in the same compound RTCP packet as the measurement 141 information block. If the measurement period is not received in the 142 same compound RTCP packet as this metric block, this metric block 143 MUST be discarded. 145 3.1. Report Block Structure 147 Delay metrics block 149 0 1 2 3 150 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 7 151 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 152 | BT=NDEL | I | resv. | block length = 6 | 153 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 154 | SSRC of Source | 155 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 156 | Mean Network Round Trip Delay | 157 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 158 | Min Network Round Trip Delay | 159 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 160 | Max Network Round Trip Delay | 161 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 162 | End System Delay - Seconds (bit 0-31) | 163 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 164 | End System Delay - Fraction (bit 0-31) | 165 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 167 Figure 1: Report Block Structure 169 3.2. Definition of Fields in Delay Metrics Report Block 171 Block type (BT): 8 bits 173 A Delay Report Block is identified by the constant NDEL. 175 [Note to RFC Editor: please replace NDEL with the IANA provided 176 RTCP XR block type for this block.] 178 Interval Metric flag (I): 2 bit 180 This field is used to indicate whether the Delay metrics are 181 Sampled, Interval or Cumulative metrics: 183 I=10: Interval Duration - the reported value applies to the 184 most recent measurement interval duration between successive 185 metrics reports. 187 I=11: Cumulative Duration - the reported value applies to the 188 accumulation period characteristic of cumulative measurements. 190 I=01: Sampled Value - the reported value is a sampled 191 instantaneous value. 193 Reserved (resv): 6 bits 195 These bits are reserved. They MUST be set to zero by senders and 196 ignored by receivers (See RFC6709 section 4.2). 198 block length: 16 bits 200 The length of this report block in 32-bit words, minus one. For 201 the Delay block, the block length is equal to 6. 203 SSRC of source: 32 bits 205 As defined in Section 4.1 of [RFC3611]. 207 Mean Network Round Trip Delay: 32 bits 209 The Mean Network Round Trip Delay is the mean value of the RTP-to- 210 RTP interface round trip delay over the measurement period, 211 expressed in units of 1/65536 seconds. This value is typically 212 determined using NTP timestamp field in the RTCP SR and LSR field 213 and DLSR field in the RTCP RR (See RFC 3550 section 6.4.1 and 214 figure 2). It also can be determined using NTP timestamp field in 215 the RTCP Receiver Reference Time Report Block and LRR field and 216 DLRR field in the DLRR Report Block (See RFC3611 section 4.5). 218 If only one measurement of Round Trip Delay is available for the 219 timespan of the report (i.e.,the measurement period) (whether 220 Interval or Cumulative), this single value SHOULD be reported as 221 the mean value. 223 If the measurement is unavailable, the value of this field with 224 all bits set to 1 MUST be reported. 226 Min Network Round Trip Delay: 32 bits 228 The Min Network Round Trip Delay is the minimum value of the RTP- 229 to-RTP interface round trip delay over the measurement period, 230 expressed in units of 1/65536 seconds. This value is typically 231 determined using NTP timestamp field in the RTCP SR and LSR field 232 and DLSR field in the RTCP RR. It also can be determined using 233 NTP timestamp field in the RTCP Receiver Reference Time Report 234 Block and LRR field and DLRR field in the 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 NTP timestamp field in the RTCP SR and LSR field 250 and DLSR field in the RTCP RR. It also can be determined using 251 NTP timestamp field in the RTCP Receiver Reference Time Report 252 Block and LRR field and DLRR field in the DLRR Report Block. 254 If only one measurement of Round Trip Delay is available for the 255 timespan of the report (i.e.,the measurement period) (whether 256 Interval or Cumulative), this single value SHOULD be reported as 257 the maximum value. 259 If the measurement is unavailable, the value of this field with 260 all bits set to 1 MUST be reported. 262 End System Delay: 64 bits 264 The End System Delay is the internal round trip delay within the 265 reporting endpoint, calculated using the nominal value of the 266 jitter buffer delay plus the accumulation/encoding and decoding/ 267 playout delay associated with the codec being used. The value of 268 this field is represented using a 64-bit NTP-format timestamp as 269 defined in [RFC5905], which is 64-bit unsigned fixed-point number 270 with the integer part in the first 32 bits and the fractional part 271 in the last 32 bits. 273 If the measurement is unavailable, the value of this field with 274 all bits set to 1 MUST be reported. 276 4. SDP Signaling 278 [RFC3611] defines the use of SDP (Session Description Protocol) 279 [RFC4566] for signaling the use of XR blocks. XR blocks MAY be used 280 without prior signaling. 282 4.1. SDP rtcp-xr-attrib Attribute Extension 284 This section augments the SDP [RFC4566] attribute "rtcp-xr" defined 285 in [RFC3611] by providing an additional value of "xr-format" to 286 signal the use of the report block defined in this document. 288 xr-format =/ xr-delay-block 290 xr-delay-block ="delay" 292 4.2. Offer/Answer Usage 294 When SDP is used in offer-answer context, the SDP Offer/Answer usage 295 defined in [RFC3611] applies. 297 5. IANA Considerations 299 New block types for RTCP XR are subject to IANA registration. For 300 general guidelines on IANA considerations for RTCP XR, refer to 301 [RFC3611]. 303 5.1. New RTCP XR Block Type value 305 This document assigns the block type value NDEL in the IANA "RTCP XR 306 Block Type Registry" to the "Delay Metrics Block". 308 [Note to RFC Editor: please replace NDEL with the IANA provided RTCP 309 XR block type for this block.] 311 5.2. New RTCP XR SDP Parameter 313 This document also registers a new parameter "delay" in the "RTCP XR 314 SDP Parameters Registry". 316 5.3. Contact information for registrations 318 The contact information for the registrations is: 320 Qin Wu (sunseawq@huawei.com) 322 101 Software Avenue, Yuhua District 323 Nanjing, Jiangsu 210012 324 China 326 6. Security Considerations 328 It is believed that this proposed RTCP XR report block introduces no 329 new security considerations beyond those described in [RFC3611]. 330 This block does not provide per-packet statistics, so the risk to 331 confidentiality documented in Section 7, paragraph 3 of [RFC3611] 332 does not apply. 334 7. Contributors 336 Geoff Hunt wrote the initial version of this document. 338 8. Acknowledgments 340 The authors gratefully acknowledge the comments and contributions 341 made by Bruce Adams, Philip Arden, Amit Arora, Bob Biskner, Kevin 342 Connor, Claus Dahm, Randy Ethier, Roni Even, Jim Frauenthal, Albert 343 Higashi, Tom Hock, Shane Holthaus, Paul Jones, Rajesh Kumar, Keith 344 Lantz, Mohamed Mostafa, Amy Pendleton, Colin Perkins, Mike Ramalho, 345 Ravi Raviraj, Albrecht Schwarz, Tom Taylor, and Hideaki Yamada,Jing 346 Zhao,Kevin Gross, Colin Perkins, Charles Eckel, Glen Zorn,Shida 347 Schubert,Barry Leiba,Sean Turner,Robert Sparks,Benoit Claise,Stephen 348 Farrell. 350 9. References 352 9.1. Normative References 354 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 355 Requirement Levels", March 1997. 357 [RFC3550] Schulzrinne, H., "RTP: A Transport Protocol for Real-Time 358 Applications", RFC 3550, July 2003. 360 [RFC3611] Friedman, T., Caceres, R., and A. Clark, "RTP Control 361 Protocol Extended Reports (RTCP XR)", November 2003. 363 [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session 364 Description Protocol", July 2006. 366 [RFC5905] Mills, D., Martin, J., Burbank, J., and W. Kasch, "Network 367 Time Protocol Version 4: Protocol and Algorithms 368 Specification", RFC 5905, June 2010. 370 [RFC6709] Carpenter, B., Aboba, B., and S. Cheshire, "Design 371 Considerations for Protocol Extensions", RFC 6709, 372 September 2012. 374 9.2. Informative References 376 [MONARCH] Hunt, G., "Monitoring Architectures for RTP", 377 ID draft-ietf-avtcore-monarch-22, September 2012. 379 [RFC6390] Clark, A. and B. Claise, "Framework for Performance Metric 380 Development", RFC 6390, October 2011. 382 [RFC6776] Hunt, G., "Measurement Identity and information Reporting 383 using SDES item and XR Block", RFC 6776, October 2012. 385 Appendix A. Change Log 387 Note to the RFC-Editor: please remove this section prior to 388 publication as an RFC. 390 A.1. draft-ietf-xrblock-rtcp-xr-delay-12 392 The following are the major changes to previous version : 394 o Remove SHOULD from reserved field and add reference to RFC6709. 396 Authors' Addresses 398 Alan Clark 399 Telchemy Incorporated 400 2905 Premiere Parkway, Suite 280 401 Duluth, GA 30097 402 USA 404 Email: alan.d.clark@telchemy.com 406 Kevin Gross 407 AVA Networks 409 Email: kevin.gross@avanw.com 411 Qin Wu 412 Huawei 413 101 Software Avenue, Yuhua District 414 Nanjing, Jiangsu 210012 415 China 417 Email: sunseawq@huawei.com