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IETF RFC 8015



Last modified on Tuesday, November 8th, 2016

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Internet Engineering Task Force (IETF)                          V. Singh
Request for Comments: 8015                                  callstats.io
Category: Standards Track                                   C. Perkins
ISSN: 2070-1721                                    University of Glasgow
                                                                A. Clark
                                                                Telchemy
                                                                R. Huang
                                                                  Huawei
                                                           November 2016


         RTP Control Protocol (RTCP) Extended Report (XR) Block
         for Independent Reporting of Burst/Gap Discard Metrics

 Abstract

   This document defines an RTP Control Protocol (RTCP) Extended Report
   (XR) block that allows the reporting of burst/gap discard metrics
   independently of the burst/gap loss metrics for use in a range of RTP
   applications.

 Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/RFC 8015.

















Singh, et al.                Standards Track                 PAGE 1 top


RFC 8015 RTCP XR Burst/Gap Discard November 2016 Copyright Notice Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Independent Burst/Gap Discard Metrics Block . . . . . . . 3 1.2. RTCP and RTCP Extended Reports . . . . . . . . . . . . . 4 1.3. Performance Metrics Framework . . . . . . . . . . . . . . 4 1.4. Applicability . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Independent Burst/Gap Discard Metrics Block . . . . . . . . . 5 3.1. Report Block Structure . . . . . . . . . . . . . . . . . 6 3.2. Definition of Fields in the Independent Burst/Gap Discard Metrics Block . . . . . . . . . . . . . . . . . . . . . . 6 3.3. Derived Metrics Based on the Reported Metrics . . . . . . 8 4. Considerations for Voice-over-IP Applications . . . . . . . . 9 5. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 9 5.1. SDP rtcp-xr Attribute Extension . . . . . . . . . . . . . 9 5.2. Offer/Answer Usage . . . . . . . . . . . . . . . . . . . 9 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 6.1. New RTCP XR Block Type Value . . . . . . . . . . . . . . 10 6.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 10 6.3. Contact Information for Registrations . . . . . . . . . . 10 7. Security Considerations . . . . . . . . . . . . . . . . . . . 10 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 8.1. Normative References . . . . . . . . . . . . . . . . . . 11 8.2. Informative References . . . . . . . . . . . . . . . . . 12 Appendix A. Metrics Represented Using the Template from RFC 6390 13 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 14 Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 Singh, et al. Standards Track PAGE 2 top

RFC 8015 RTCP XR Burst/Gap Discard November 2016 1. Introduction 1.1. Independent Burst/Gap Discard Metrics Block This document defines a new block type that extends the metrics defined in [RFC 7003]. The new block type reports the proportion of packets discarded in a burst by the de-jitter buffer at the receiver. The number of packets discarded depends on the de-jitter buffer algorithm implemented by the endpoint. The new report block defined in this document is different from the one defined in [RFC 7003]. The metrics in [RFC 7003] depend on the metrics in the burst/gap loss metric defined in [RFC 6958]. Consequently, an endpoint that sends a Burst/Gap Discard Metrics Block [RFC 7003] also needs to send a Burst/Gap Loss Metrics Block [RFC 6958]. The combined usage is useful when an endpoint observes correlated packet losses and discard. However, when the burst of packet losses and discards do not occur simultaneously, the application could prefer to send a concise report block that just reports the burst/gap of discarded packets. The report block in this document provides the complete information and does not require additional report blocks. That is, this block reports the total number of packets discarded, the total burst duration, and the total number of bursts. All of these metrics are missing in [RFC 7003]. This block provides information on transient network issues. Burst/ gap metrics are typically used in cumulative reports; however, they can also be used in interval reports (see the Interval Metric flag in Section 3.2). The variation in the number of packet discards in a burst affects the user experience. Based on the metrics reported in the block, the sending endpoint can change the packetization interval, vary the bitrate, etc. The report can additionally be used for diagnostics [RFC 6792]. The metric belongs to the class of transport-related end-system metrics defined in [RFC 6792]. The definitions of "burst", "gap", "loss", and "discard" are consistent with the definitions in [RFC 3611]. To accommodate a range of de-jitter buffer algorithms and packet discard logic that can be used by implementers, the method used to distinguish between bursts and gaps uses an equivalent method to that defined in Section 4.7.2 of [RFC 3611]. Note that reporting the specific de-jitter buffer algorithm and/or the packet discard logic is out of the scope of this document. Singh, et al. Standards Track PAGE 3 top

RFC 8015 RTCP XR Burst/Gap Discard November 2016 1.2. RTCP and RTCP Extended Reports The use of RTCP for reporting is defined in [RFC 3550]. [RFC 3611] defined an extensible structure for reporting using an RTCP Extended Report (XR). This document defines a new Extended Report block for use with [RFC 3550] and [RFC 3611]. 1.3. Performance Metrics Framework The Performance Metrics Framework [RFC 6390] provides guidance on the definition and specification of performance metrics. The RTP Monitoring Framework [RFC 6792] provides guidelines for reporting the block format using RTCP XR. The metrics block described in this document is in accordance with the guidelines in [RFC 6390] and [RFC 6792]. 1.4. Applicability These metrics are applicable to a range of RTP applications that contain de-jitter buffers at the receiver to smooth variation in packet-arrival time and don't use stream repair means, e.g., Forward Error Correction (FEC) [FLEX_FEC] and/or retransmission [RFC 4588]. 2. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC 2119]. In addition, the following terms are defined: Received, Lost, and Discarded A packet is regarded as "lost" if it fails to arrive within an implementation-specific time window. A packet that arrives within this time window but is too early to be played out, too late to be played out, or thrown away before playout due to packet duplication or redundancy is be recorded as "discarded". A packet SHALL NOT be regarded as "discarded" if it arrives within this time window but is dropped during decoding by some higher-layer decoder, e.g., due to a decoding error. Each packet is classified as one of "received" (or "OK"), "discarded", or "lost". The metric "cumulative number of packets lost" defined in [RFC 3550] reports a count of packets lost from the media stream (single synchronization source (SSRC) within a single RTP session). Similarly, the metric "number of packets discarded" defined in [RFC 7002] reports a count of packets discarded from the media stream (single SSRC within a single RTP session) arriving at the Singh, et al. Standards Track PAGE 4 top

RFC 8015 RTCP XR Burst/Gap Discard November 2016 receiver. Another metric, defined in [RFC 5725], is available to report on packets that are not recovered by any repair techniques that are in use. Note that the term "discard" defined here builds on the "discard" definition in [RFC 3611] but extends the concept to take into account packet duplication and reports different types of discard counts [RFC 7002]. Bursts and Gaps The terms "burst" and "gap" are used in a manner consistent with that of RTCP XR [RFC 3611]. RTCP XR views an RTP stream as being divided into bursts, which are periods during which the discard rate is high enough to cause noticeable quality degradation (generally a discard rate over 5 percent), and gaps, which are periods during which discarded packets are infrequent, and hence quality is generally acceptable. 3. Independent Burst/Gap Discard Metrics Block Metrics in this block report on burst/gap discard in the stream arriving at the RTP system. Measurements of these metrics are made at the receiving end of the RTP stream. Instances of this metrics block use the synchronization source (SSRC) to refer to the separate auxiliary Measurement Information Block [RFC 6776], which describes measurement periods in use (see [RFC 6776], Section 4.2). This metrics block relies on the measurement period in the Measurement Information Block indicating the span of the report. Senders MUST send this block in the same compound RTCP packet as the Measurement Information Block. Receivers MUST verify that the measurement period is received in the same compound RTCP packet as this metrics block. If not, this metrics block MUST be discarded. Singh, et al. Standards Track PAGE 5 top

RFC 8015 RTCP XR Burst/Gap Discard November 2016 3.1. Report Block Structure The structure of the Independent Burst/Gap Discard Metrics Block is as follows. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BT=35 | I | resv | Block Length = 5 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SSRC of Source | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Threshold | Sum of Burst Durations (ms) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Packets Discarded in Bursts | Number of | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Bursts | Total Packets Expected in Bursts | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Discard Count | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: Report Block Structure 3.2. Definition of Fields in the Independent Burst/Gap Discard Metrics Block Block Type (BT): 8 bits An Independent Burst/Gap Discard Metrics Block is identified by the constant 35. Interval Metric flag (I): 2 bits This field is used to indicate whether the burst/gap discard metrics are Sampled, Interval, or Cumulative metrics [RFC 6792]: I=10: Interval Duration - the reported value applies to the most recent measurement interval duration between successive metrics reports. I=11: Cumulative Duration - the reported value applies to the accumulation period characteristic of cumulative measurements. In this document, burst/gap discard metrics can only be measured over definite intervals and cannot be sampled. Also, the value I=00 is reserved for future use. Senders MUST NOT use the values I=00 or I=01. If a block is received with I=00 or I=01, the receiver MUST discard the block. Singh, et al. Standards Track PAGE 6 top

RFC 8015 RTCP XR Burst/Gap Discard November 2016 Reserved (resv): 6 bits These bits are reserved. They MUST be set to zero by senders and ignored by receivers (see [RFC 6709], Section 4.2). Block Length: 16 bits The length of this report block in 32-bit words, minus one. For the Independent Burst/Gap Discard Metrics Block, the block length is equal to 5. The block MUST be discarded if the block length is set to a different value. SSRC of Source: 32 bits As defined in Section 4 of [RFC 3611]. Threshold: 8 bits The Threshold is equivalent to Gmin in [RFC 3611], i.e., the number of successive packets that have to be received prior to, and following, a discarded packet in order for that discarded packet to be regarded as part of a gap. Note that the Threshold is set in accordance with the Gmin calculation defined in Section 4.7.2 of [RFC 3611]. Sum of Burst Durations (ms): 24 bits The total duration of bursts of discarded packets in the period of the report (Interval or Cumulative). The measured value is an unsigned value. If the measured value exceeds 0xFFFFFD, the value 0xFFFFFE MUST be reported to indicate an over-range measurement. If the measurement is unavailable, the value 0xFFFFFF MUST be reported. Packets Discarded in Bursts: 24 bits The total number of packets discarded during discard bursts, as defined in Section 3.2 of [RFC 7002]. Singh, et al. Standards Track PAGE 7 top

RFC 8015 RTCP XR Burst/Gap Discard November 2016 Number of Bursts: 16 bits The number of discard bursts in the period of the report (Interval or Cumulative). The measured value is an unsigned value. If the measured value exceeds 0xFFFD, the value 0xFFFE MUST be reported to indicate an over-range measurement. If the measurement is unavailable, the value 0xFFFF MUST be reported. Total Packets Expected in Bursts: 24 bits The total number of packets expected during the discard bursts (that is, the sum of received packets and lost packets). The metric is defined in [RFC 7003]. Discard Count: 32 bits Number of packets discarded over the period (Interval or Cumulative) covered by this report, as defined in Section 3.2 of [RFC 7002]. 3.3. Derived Metrics Based on the Reported Metrics The metrics described here are intended to be used in conjunction with information from the Measurement Information Block [RFC 6776]. These metrics provide the following information relevant to statistical parameters (depending on cumulative of interval measures), for example: o The average discarded burst size, which can be calculated by dividing the metric "Packets Discarded in Bursts" by the "Number of Bursts". o The average burst duration, which can be calculated by dividing the metric "Sum of Burst Durations (ms)" by the "Number of Bursts". Singh, et al. Standards Track PAGE 8 top

RFC 8015 RTCP XR Burst/Gap Discard November 2016 4. Considerations for Voice-over-IP Applications This metrics block is applicable to a broad range of RTP applications. Where the metric is used with a Voice-over-IP (VoIP) application and the stream repair means is not available, the following considerations apply. RTCP XR views a call as being divided into bursts, which are periods during which the discard rate is high enough to cause noticeable call quality degradation (generally a discard rate over 5 percent) and gaps, which are periods during which discarded packets are infrequent, and hence call quality is generally acceptable. If voice activity detection is used, the burst/gap duration is determined as if silence packets had been sent, i.e., a period of silence in excess of Gmin packets will terminate a burst condition. The RECOMMENDED value for the threshold Gmin in [RFC 3611] results in a burst being a period of time during which the call quality is degraded to a similar extent to a typical pulse code modulation (PCM) severely errored second. 5. SDP Signaling [RFC 3611] defines the use of SDP (Session Description Protocol) [RFC 4566] for signaling the use of XR blocks. XR blocks can be used without prior signaling. 5.1. SDP rtcp-xr Attribute Extension This section augments the SDP [RFC 4566] attribute "rtcp-xr" defined in [RFC 3611] by providing an additional value of "xr-format" to signal the use of the report block defined in this document. The ABNF [RFC 5234] syntax is as follows. xr-format =/ xr-ind-bgd-block xr-ind-bgd-block = "ind-burst-gap-discard" 5.2. Offer/Answer Usage When SDP is used in Offer/Answer context, the SDP Offer/Answer usage defined in [RFC 3611] for unilateral "rtcp-xr" attribute parameters applies. For detailed usage in Offer/Answer for unilateral parameters, refer to Section 5.2 of [RFC 3611]. Singh, et al. Standards Track PAGE 9 top

RFC 8015 RTCP XR Burst/Gap Discard November 2016 6. IANA Considerations New block types for RTCP XR are subject to IANA registration. For general guidelines on IANA considerations for RTCP XR, refer to [RFC 3611]. 6.1. New RTCP XR Block Type Value This document assigns the block type value 35 in the IANA "RTP Control Protocol Extended Reports (RTCP XR) Block Type Registry" to the "Independent Burst/Gap Discard Metrics Block". 6.2. New RTCP XR SDP Parameter This document also registers a new parameter "ind-burst-gap-discard" in the "RTP Control Protocol Extended Reports (RTCP XR) Session Description Protocol (SDP) Parameters Registry". 6.3. Contact Information for Registrations The contact information for the registrations is: ART Area Directors <art-ads@ietf.org> 7. Security Considerations This block does not provide per-packet statistics, so the risk to confidentiality documented in Section 7, paragraph 3 of [RFC 3611] does not apply. However, the gap indicated within this block could be used to detect the timing of other events on the path between the sender and receiver. For example, a competing multimedia stream might cause a discard burst for the duration of the stream, allowing the receiver of this block to know when the competing stream was active. This risk is not a significant threat since the only information leaked is the timing of the discard, not the cause. Where this is a concern, the implementation SHOULD apply encryption and authentication to this report block. For example, this can be achieved by using the Audio-Visual Profile with Feedback (AVPF) profile together with the Secure RTP profile, as defined in [RFC 3711]; an appropriate combination of those two profiles ("SAVPF") is specified in [RFC 5124]. Besides this, it is believed that this RTCP XR block introduces no new security considerations beyond those described in [RFC 3611]. Singh, et al. Standards Track PAGE 10 top

RFC 8015 RTCP XR Burst/Gap Discard November 2016 8. References 8.1. Normative References [RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC 2119, March 1997, <http://www.rfc-editor.org/info/RFC 2119>. [RFC 3550] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson, "RTP: A Transport Protocol for Real-Time Applications", STD 64, RFC 3550, DOI 10.17487/RFC 3550, July 2003, <http://www.rfc-editor.org/info/RFC 3550>. [RFC 3611] Friedman, T., Ed., Caceres, R., Ed., and A. Clark, Ed., "RTP Control Protocol Extended Reports (RTCP XR)", RFC 3611, DOI 10.17487/RFC 3611, November 2003, <http://www.rfc-editor.org/info/RFC 3611>. [RFC 3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, "The Secure Real-time Transport Protocol (SRTP)", RFC 3711, DOI 10.17487/RFC 3711, March 2004, <http://www.rfc-editor.org/info/RFC 3711>. [RFC 4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session Description Protocol", RFC 4566, DOI 10.17487/RFC 4566, July 2006, <http://www.rfc-editor.org/info/RFC 4566>. [RFC 5124] Ott, J. and E. Carrara, "Extended Secure RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/SAVPF)", RFC 5124, DOI 10.17487/RFC 5124, February 2008, <http://www.rfc-editor.org/info/RFC 5124>. [RFC 5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", STD 68, RFC 5234, DOI 10.17487/RFC 5234, January 2008, <http://www.rfc-editor.org/info/RFC 5234>. [RFC 5725] Begen, A., Hsu, D., and M. Lague, "Post-Repair Loss RLE Report Block Type for RTP Control Protocol (RTCP) Extended Reports (XRs)", RFC 5725, DOI 10.17487/RFC 5725, February 2010, <http://www.rfc-editor.org/info/RFC 5725>. [RFC 6776] Clark, A. and Q. Wu, "Measurement Identity and Information Reporting Using a Source Description (SDES) Item and an RTCP Extended Report (XR) Block", RFC 6776, DOI 10.17487/RFC 6776, October 2012, <http://www.rfc-editor.org/info/RFC 6776>. Singh, et al. Standards Track PAGE 11 top

RFC 8015 RTCP XR Burst/Gap Discard November 2016 [RFC 7003] Clark, A., Huang, R., and Q. Wu, Ed., "RTP Control Protocol (RTCP) Extended Report (XR) Block for Burst/Gap Discard Metric Reporting", RFC 7003, DOI 10.17487/RFC 7003, September 2013, <http://www.rfc-editor.org/info/RFC 7003>. 8.2. Informative References [FLEX_FEC] Singh, V., Begen, A., Zanaty, M., and G. Mandyam, "RTP Payload Format for Flexible Forward Error Correction (FEC)", Work in Progress, draft-ietf-payload-flexible-fec- scheme-03, October 2016. [RFC 4588] Rey, J., Leon, D., Miyazaki, A., Varsa, V., and R. Hakenberg, "RTP Retransmission Payload Format", RFC 4588, DOI 10.17487/RFC 4588, July 2006, <http://www.rfc-editor.org/info/RFC 4588>. [RFC 6390] Clark, A. and B. Claise, "Guidelines for Considering New Performance Metric Development", BCP 170, RFC 6390, DOI 10.17487/RFC 6390, October 2011, <http://www.rfc-editor.org/info/RFC 6390>. [RFC 6709] Carpenter, B., Aboba, B., Ed., and S. Cheshire, "Design Considerations for Protocol Extensions", RFC 6709, DOI 10.17487/RFC 6709, September 2012, <http://www.rfc-editor.org/info/RFC 6709>. [RFC 6792] Wu, Q., Ed., Hunt, G., and P. Arden, "Guidelines for Use of the RTP Monitoring Framework", RFC 6792, DOI 10.17487/RFC 6792, November 2012, <http://www.rfc-editor.org/info/RFC 6792>. [RFC 6958] Clark, A., Zhang, S., Zhao, J., and Q. Wu, Ed., "RTP Control Protocol (RTCP) Extended Report (XR) Block for Burst/Gap Loss Metric Reporting", RFC 6958, DOI 10.17487/RFC 6958, May 2013, <http://www.rfc-editor.org/info/RFC 6958>. [RFC 7002] Clark, A., Zorn, G., and Q. Wu, "RTP Control Protocol (RTCP) Extended Report (XR) Block for Discard Count Metric Reporting", RFC 7002, DOI 10.17487/RFC 7002, September 2013, <http://www.rfc-editor.org/info/RFC 7002>. Singh, et al. Standards Track PAGE 12 top

RFC 8015 RTCP XR Burst/Gap Discard November 2016 Appendix A. Metrics Represented Using the Template from RFC 6390 a. Threshold Metric * Defined in item a of Appendix A of [RFC 7003]. b. Sum of Burst Durations (ms) * Metric Name: Sum of Burst Durations with Discarded RTP Packets. * Metric Description: The total duration of bursts of discarded RTP packets in the period of the report. * Method of Measurement or Calculation: See Section 3.2, Sum of Burst Durations definition. * Units of Measurement: See Section 3.2, Sum of Burst Durations definition. * Measurement Point(s) with Potential Measurement Domain: See Section 3, first paragraph. * Measurement Timing: See Section 3, second paragraph for measurement timing and Section 3.2 for Interval Metric flag. * Use and Applications: See Section 1.4. * Reporting Model: See [RFC 3611]. c. Packets Discarded in Bursts Metric * Defined in item b of Appendix A of [RFC 7003]. d. Number of Bursts * Metric Name: Number of discard bursts in RTP. * Metric Description: The total number of bursts with discarded RTP packets in the period of the report. * Method of Measurement or Calculation: See Section 3.2, Number of Bursts definition. * Units of Measurement: See Section 3.2 for the Number of Bursts definition. Singh, et al. Standards Track PAGE 13 top

RFC 8015 RTCP XR Burst/Gap Discard November 2016 * Measurement Point(s) with Potential Measurement Domain: See Section 3, first paragraph. * Measurement Timing: See Section 3, second paragraph for measurement timing and Section 3.2 for Interval Metric flag. * Use and Applications: See Section 1.4. * Reporting Model: See [RFC 3611]. e. Total Packets Expected in Bursts Metric * Defined in item c of Appendix A of [RFC 7003]. f. Discard Count * Defined in Appendix A of [RFC 7002]. Acknowledgments The authors would like to thank Ben Campbell, Stephen Farrell, Paul Kyzivat, Shucheng LIU, Jan Novak, and Dan Romascanu for providing valuable feedback on this document. Contributors Qin Wu, Rachel Huang, and Alan Clark wrote RFC 7003, which this document extends. Singh, et al. Standards Track PAGE 14 top

RFC 8015 RTCP XR Burst/Gap Discard November 2016 Authors' Addresses Varun Singh CALLSTATS I/O Oy Runeberginkatu 4c A 4 Helsinki 00100 Finland Email: varun@callstats.io URI: https://www.callstats.io/about Colin Perkins University of Glasgow School of Computing Science Glasgow G12 8QQ United Kingdom Email: csp@csperkins.org Alan Clark Telchemy Incorporated 2905 Premiere Parkway, Suite 280 Duluth, GA 30097 United States of America Email: alan.d.clark@telchemy.com Rachel Huang Huawei Technologies Co., Ltd. 101 Software Avenue, Yuhua District Nanjing, Jiangsu 210012 China Email: Rachel@huawei.com Singh, et al. Standards Track PAGE 15 top

RFC TOTAL SIZE: 29547 bytes PUBLICATION DATE: Tuesday, November 8th, 2016 LEGAL RIGHTS: The IETF Trust (see BCP 78)


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