idnits 2.17.1 draft-ietf-xrblock-rtcp-xr-discard-05.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 == Using lowercase 'not' together with uppercase 'MUST', 'SHALL', 'SHOULD', or 'RECOMMENDED' is not an accepted usage according to RFC 2119. Please use uppercase 'NOT' together with RFC 2119 keywords (if that is what you mean). Found 'MUST not' in this paragraph: This field is used to indicate whether the Discard Count Metric is an Interval or Cumulative metric, Sample metric [MONARCH],that is, whether the reported values applies to the most recent measurement interval duration between successive metrics reports (I=10) (the Interval Duration) or to the accumulation period characteristic of cumulative measurements (I=11) (the Cumulative Duration) or is a sampled instantaneous value (I=01) (Sampled Value). In this document, Discard Count Metric is not measured at a particular time instant but over one or several reporting intervals. Therefore Discard Count Metric MUST not be chosen as Sampled Metric. == Using lowercase 'not' together with uppercase 'MUST', 'SHALL', 'SHOULD', or 'RECOMMENDED' is not an accepted usage according to RFC 2119. Please use uppercase 'NOT' together with RFC 2119 keywords (if that is what you mean). Found 'MUST not' in this paragraph: An endpoint MAY send only one of the discard types (early, late, duplication packets discard) in one RTCP report or choose to report early (DT=1) and late (DT=2), duplication packets discard (DT=0) in separate block. It MAY also send the combined early and late discard type (DT=2) in one RTCP compound packet, but not any other combination of the three Discard Types. The endpoint MUST not report the the total number of discarded packets covering all three discard types. Instead, two separate report blocks should be used to carry duplication packets discard and the combined early and late discard respectively. -- The document date (July 10, 2012) is 4306 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) ** 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 (~~), 5 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: January 11, 2013 Telchemy 6 G. Zorn 7 Network Zen 8 Q. Wu 9 Huawei 10 July 10, 2012 12 RTCP XR Report Block for Discard Count metric Reporting 13 draft-ietf-xrblock-rtcp-xr-discard-05.txt 15 Abstract 17 This document defines an RTCP XR Report Block that allows the 18 reporting of a simple discard count metric for use in a range of RTP 19 applications. 21 Status of this Memo 23 This Internet-Draft is submitted in full conformance with the 24 provisions of BCP 78 and BCP 79. 26 Internet-Drafts are working documents of the Internet Engineering 27 Task Force (IETF). Note that other groups may also distribute 28 working documents as Internet-Drafts. The list of current Internet- 29 Drafts is at http://datatracker.ietf.org/drafts/current/. 31 Internet-Drafts are draft documents valid for a maximum of six months 32 and may be updated, replaced, or obsoleted by other documents at any 33 time. It is inappropriate to use Internet-Drafts as reference 34 material or to cite them other than as "work in progress." 36 This Internet-Draft will expire on January 11, 2013. 38 Copyright Notice 40 Copyright (c) 2012 IETF Trust and the persons identified as the 41 document authors. All rights reserved. 43 This document is subject to BCP 78 and the IETF Trust's Legal 44 Provisions Relating to IETF Documents 45 (http://trustee.ietf.org/license-info) in effect on the date of 46 publication of this document. Please review these documents 47 carefully, as they describe your rights and restrictions with respect 48 to this document. Code Components extracted from this document must 49 include Simplified BSD License text as described in Section 4.e of 50 the Trust Legal Provisions and are provided without warranty as 51 described in the Simplified BSD License. 53 Table of Contents 55 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 56 1.1. Discard Count Report Block . . . . . . . . . . . . . . . . 3 57 1.2. RTCP and RTCP XR Reports . . . . . . . . . . . . . . . . . 3 58 1.3. Performance Metrics Framework . . . . . . . . . . . . . . 3 59 1.4. Applicability . . . . . . . . . . . . . . . . . . . . . . 3 60 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 61 2.1. Standards Language . . . . . . . . . . . . . . . . . . . . 4 62 3. Discard Count Metric Report Block . . . . . . . . . . . . . . 5 63 3.1. Report Block Structure . . . . . . . . . . . . . . . . . . 5 64 3.2. Definition of Fields in Discard Count Metric Report 65 Block . . . . . . . . . . . . . . . . . . . . . . . . . . 5 66 4. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 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. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11 73 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 74 8.1. Normative References . . . . . . . . . . . . . . . . . . . 12 75 8.2. Informative References . . . . . . . . . . . . . . . . . . 12 76 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13 78 1. Introduction 80 1.1. Discard Count Report Block 82 This document defines a new block type to augment those defined in 83 [RFC3611] for use in a range of RTP applications. The new block type 84 supports the reporting of the number of packets which are received 85 correctly but are never played out, typically because they arrive too 86 late to be played out (buffer underflow) or too early (buffer 87 overflow). The metric is applicable both to systems which use packet 88 loss repair techniques (such as forward error correction [RFC5109] or 89 retransmission [RFC4588]) and to those which do not. 91 This metric is useful for identifying the existence, and 92 characterising the severity, of a packet transport problem which may 93 affect users' perception of a service delivered over RTP. 95 The metric belongs to the class of transport-related terminal metrics 96 defined in [MONARCH]. 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 document defines a new Extended Report block. The 103 use of Extended Report blocks is defined by [RFC3611]. 105 1.3. Performance Metrics Framework 107 The Performance Metrics Framework [RFC6390] provides guidance on the 108 definition and specification of performance metrics. The RTP 109 Monitoring Architectures [MONARCH] provides guideline for reporting 110 block format using RTCP XR. The Metrics Block described in this 111 document are in accordance with the guidelines in [RFC6390] and 112 [MONARCH]. 114 1.4. Applicability 116 This metric is believed to be applicable to a large class of RTP 117 applications which use a jitter buffer. 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 In addition, the following terms are defined: 129 Received, Lost and Discarded 131 A packet shall be regarded as lost if it fails to arrive within an 132 implementation-specific time window. A packet that arrives within 133 this time window but is too early or late to be played out or 134 thrown away before playout due to packet duplication or redundancy 135 shall be regarded as discarded. A packet shall be classified as 136 one of received (or OK), discarded or lost. The Discard Count 137 Metric counts only discarded packets. The metric "cumulative 138 number of packets lost" defined in [RFC3550] reports a count of 139 packets lost from the media stream (single SSRC within single RTP 140 session). Similarly the metric "number of packets discarded" 141 reports a count of packets discarded from the media stream (single 142 SSRC within single RTP session) arriving at the receiver. Another 143 metric defined in [RFC5725] is available to report on packets 144 which are not recovered by any repair techniques which may be in 145 use. 147 3. Discard Count Metric Report Block 149 3.1. Report Block Structure 151 0 1 2 3 152 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 7 153 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 154 | BT=PDC | I |DT | resv.| block length = 2 | 155 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 156 | SSRC of Source | 157 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 158 | number of packets discarded | 159 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 161 Figure 1: Report Block Structure 163 3.2. Definition of Fields in Discard Count Metric Report Block 165 Block type (BT): 8 bits 167 A Discard Count Metric Report Block is identified by the constant 168 PDC. 170 [Note to RFC Editor: please replace PDC with the IANA provided 171 RTCP XR block type for this block.] 173 Interval Metric flag (I): 2 bits 175 This field is used to indicate whether the Discard Count Metric is 176 an Interval or Cumulative metric, Sample metric [MONARCH],that is, 177 whether the reported values applies to the most recent measurement 178 interval duration between successive metrics reports (I=10) (the 179 Interval Duration) or to the accumulation period characteristic of 180 cumulative measurements (I=11) (the Cumulative Duration) or is a 181 sampled instantaneous value (I=01) (Sampled Value). In this 182 document, Discard Count Metric is not measured at a particular 183 time instant but over one or several reporting intervals. 184 Therefore Discard Count Metric MUST not be chosen as Sampled 185 Metric. 187 Discard Type (DT): 2bits 189 This field is used to identify the discard type used in this 190 report block. The discard type is defined as follows: 192 00: Report packet discarded or being thrown away before playout 193 due to packets duplication. 195 01: Report packet discarded due to too early to be played out. 197 10: Report packet discarded due to too late to be played out. 199 11: Report the total number of discarded packets due to both 200 early and late to be played out. 202 An endpoint MAY send only one of the discard types (early, late, 203 duplication packets discard) in one RTCP report or choose to 204 report early (DT=1) and late (DT=2), duplication packets discard 205 (DT=0) in separate block. It MAY also send the combined early and 206 late discard type (DT=2) in one RTCP compound packet, but not any 207 other combination of the three Discard Types. The endpoint MUST 208 not report the the total number of discarded packets covering all 209 three discard types. Instead, two separate report blocks should 210 be used to carry duplication packets discard and the combined 211 early and late discard respectively. 213 Reserved (resv): 4 bits 215 These bits are reserved. They SHOULD be set to zero by senders 216 and MUST be ignored by receivers. 218 block length: 16 bits 220 The length of this report block in 32-bit words, minus one. For 221 the Discard Count block, the block length is equal to 2. 223 SSRC of source: 32 bits 225 As defined in Section 4.1 of [RFC3611]. 227 number of packets discarded: 32 bits 229 Number of packets discarded over the period (Interval or 230 Cumulative) covered by this report. 232 If the measured value exceeds 0xFFFFFFFD, the value 0xFFFFFFFE 233 MUST be reported to indicate an over-range measurement. If the 234 measurement is unavailable, the value 0xFFFFFFFF MUST be reported. 236 Note that the number of packets expected in the period associated 237 with this metric (whether interval or cumulative) is available 238 from the difference between a pair of extended sequence numbers in 239 the Measurement Information block [MEASI], so need not be repeated 240 in this block. 242 4. SDP Signaling 244 [RFC3611] defines the use of SDP (Session Description Protocol) 245 [RFC4566] for signaling the use of XR blocks. XR blocks MAY be used 246 without prior signaling. 248 This section augments the SDP [RFC4566] attribute "rtcp-xr" defined 249 in [RFC3611] by providing an additional value of "xr-format" to 250 signal the use of the report block defined in this document. 252 rtcp-xr-attrib = "a=" "rtcp-xr" ":" [xr-format *(SP xr-format)] CRLF 254 (defined in [RFC3611]) 256 xr-format =/ xr-pdc-block 258 xr-pdc-block = "pkt-dscrd-count" 260 5. IANA Considerations 262 New block types for RTCP XR are subject to IANA registration. For 263 general guidelines on IANA considerations for RTCP XR, refer to 264 [RFC3611]. 266 5.1. New RTCP XR Block Type value 268 This document assigns the block type value PDC in the IANA "RTCP XR 269 Block Type Registry" to the "Discard Count Metrics Block". 271 [Note to RFC Editor: please replace PDC with the IANA provided RTCP 272 XR block type for this block.] 274 5.2. New RTCP XR SDP Parameter 276 This document also registers a new parameter "pkt-dscrd" in the "RTCP 277 XR SDP Parameters Registry". 279 5.3. Contact information for registrations 281 The following contact information is provided for all 282 registrations in this document: 284 Qin Wu (sunseawq@huawei.com) 286 101 Software Avenue, Yuhua District 287 Nanjing, Jiangsu 210012 288 China 290 6. Security Considerations 292 It is believed that this proposed RTCP XR report block introduces no 293 new security considerations beyond those described in [RFC3611]. 294 This block does not provide per-packet statistics so the risk to 295 confidentiality documented in Section 7, paragraph 3 of [RFC3611] 296 does not apply. 298 7. Acknowledgments 300 The authors gratefully acknowledge the comments and contributions 301 made by Bruce Adams, Philip Arden, Amit Arora, Bob Biskner, Kevin 302 Connor, Claus Dahm, Randy Ethier, Roni Even, Jim Frauenthal, Albert 303 Higashi, Tom Hock, Shane Holthaus, Paul Jones, Rajesh Kumar, Keith 304 Lantz, Mohamed Mostafa, Amy Pendleton, Colin Perkins, Mike Ramalho, 305 Ravi Raviraj, Albrecht Schwarz, Tom Taylor, and Hideaki Yamada,Kevin 306 Gross, Varun Singh,Claire Bi, Roni Even, Dan Romascanu. 308 8. References 310 8.1. Normative References 312 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 313 Requirement Levels", March 1997. 315 [RFC3550] Schulzrinne, H., "RTP: A Transport Protocol for Real-Time 316 Applications", RFC 3550, July 2003. 318 [RFC3611] Friedman, T., Caceres, R., and A. Clark, "RTP Control 319 Protocol Extended Reports (RTCP XR)", November 2003. 321 [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session 322 Description Protocol", July 2006. 324 8.2. Informative References 326 [MEASI] Hunt, G., "Measurement Identity and information Reporting 327 using SDES item and XR Block", 328 ID draft-ietf-xrblock-rtcp-xr-meas-identity-06, 329 April 2012. 331 [MONARCH] Wu, Q., "Monitoring Architectures for RTP", 332 ID draft-ietf-avtcore-monarch-12, April 2012. 334 [RFC4588] Rey, J., "RTP Retransmission Payload Format", RFC 4588, 335 July 2006. 337 [RFC5109] Li, A., "RTP Payload Format for Generic Forward Error 338 Correction", RFC 5109, July 2006. 340 [RFC5725] Begen, A., "RTCP XR Report Block for Post-Repair Loss 341 metric Reporting", RFC 5725, February 2010. 343 [RFC6390] Clark, A. and B. Claise, "Framework for Performance Metric 344 Development", RFC 6390, October 2011. 346 Authors' Addresses 348 Geoff Hunt 349 Unaffiliated 351 Email: r.geoff.hunt@gmail.com 353 Alan Clark 354 Telchemy Incorporated 355 2905 Premiere Parkway, Suite 280 356 Duluth, GA 30097 357 USA 359 Email: alan.d.clark@telchemy.com 361 Glen Zorn 362 Network Zen 363 77/440 Soi Phoomjit, Rama IV Road 364 Phra Khanong, Khlong Toie 365 Bangkok 10110 366 Thailand 368 Phone: +66 (0) 87 502 4274 369 Email: gwz@net-zen.net 371 Qin Wu 372 Huawei 373 101 Software Avenue, Yuhua District 374 Nanjing, Jiangsu 210012 375 China 377 Email: sunseawq@huawei.com