Audio/Video Transport Working Group
Internet Engineering Task Force (IETF)                          A. Clark
Internet-Draft
Request for Comments: 7003                                      Telchemy
Intended status:
Category: Standards Track                                       R. Huang
Expires: October 28, 2013
ISSN: 2070-1721                                               Q. Wu, Ed.
                                                                  Huawei
                                                          April 26,
                                                             August 2013

         RTP Control Protocol(RTCP) Protocol (RTCP) Extended Report (XR) Block
                 for Burst/Gap Discard metric Metric Reporting
          draft-ietf-xrblock-rtcp-xr-burst-gap-discard-14.txt

Abstract

   This document defines an RTP Control Protocol(RTCP) Protocol (RTCP) Extended Report
   (XR) Block block that allows the reporting of Burst burst and Gap Discard gap discard metrics
   for use in a range of RTP applications.

Status of this This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents an Internet Standards Track document.

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   (IETF).  Note that other groups may also distribute
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   Internet-Drafts are draft documents valid the IETF community.  It has
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   This Internet-Draft will expire on October 28, 2013.
   http://www.rfc-editor.org/info/rfc7003.

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Table of Contents
   1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3 ....................................................2
      1.1.  Burst and Gap Burst/Gap Discard Report Metrics Block . . . . . . . . . . . .  3 ............................2
      1.2. RTCP and RTCP XR Extended Reports . . . . . . . . . . . . . . . . .  3 .............................3
      1.3. Performance Metrics Framework  . . . . . . . . . . . . . .  3 ..............................3
      1.4. Applicability  . . . . . . . . . . . . . . . . . . . . . .  4 ..............................................3
   2. Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  5
     2.1.  Standards Language . . . . . . . . . . . . . . . . . . . .  5 .....................................................3
   3. Burst/Gap Discard Metrics Block  . . . . . . . . . . . . . . . . . . .  6 .................................4
      3.1. Report Block Structure . . . . . . . . . . . . . . . . . .  6 .....................................5
      3.2. Definition of Fields in Burst/Gap Discard Report Metrics Block . .  6 ....5
      3.3. Derived metrics based Metrics Based on reported metrics  . . . . . . . .  8 Reported Metrics ..................7
   4. Considerations for Voice-over-IP applications  . . . . . . . . 10 Applications ...................7
   5. SDP Signaling  . . . . . . . . . . . . . . . . . . . . . . . . 11 ...................................................8
      5.1. SDP rtcp-xr-attrib rtcp-xr Attribute Extension . . . . . . . . . . 11 ............................8
      5.2. Offer/Answer Usage . . . . . . . . . . . . . . . . . . . . 11 .........................................8
   6. IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 12 .............................................8
      6.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 12 Value ...............................8
      6.2. New RTCP XR SDP Parameter  . . . . . . . . . . . . . . . . 12 ..................................9
      6.3. Contact information Information for registrations  . . . . . . . . . . 12 Registrations ......................9
   7. Security Considerations  . . . . . . . . . . . . . . . . . . . 13 .........................................9
   8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 14 ....................................................9
   9. Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 15 .................................................9
   10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16 ....................................................10
      10.1. Normative References . . . . . . . . . . . . . . . . . . . 16 .....................................10
      10.2. Informative References . . . . . . . . . . . . . . . . . . 16 ...................................10
   Appendix A.  Metrics represented using RFC6390 Represented Using the Template  . . . . . 18
   Appendix B.  Change Log  . . . . . . . . . . . . . . . . . . . . . 21
     B.1.  draft-ietf-xrblock-rtcp-xr-burst-gap-discard-14  . . . . . 21
     B.2.  draft-ietf-xrblock-rtcp-xr-burst-gap-discard-13  . . . . . 21
     B.3.  draft-ietf-xrblock-rtcp-xr-burst-gap-discard-12  . . . . . 21
     B.4.  draft-ietf-xrblock-rtcp-xr-burst-gap-discard-11  . . . . . 21
     B.5.  draft-ietf-xrblock-rtcp-xr-burst-gap-discard-10  . . . . . 21
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 22 from RFC 6390..12

1.  Introduction

1.1.  Burst and Gap  Burst/Gap Discard Report Metrics Block

   This document defines a new block type to augment those defined in
   [RFC3611] for use in a range of RTP applications.  The new block type
   supports the reporting of the proportion of packets discarded by the
   jitter buffer at the receiver, using packet discard logic according
   to the jitter buffer algorithms.  The discards during discard bursts
   are reported, together with the number of bursts.  This block is
   intended to be used in conjunction with [DISCARD] [RFC7002], which provides the
   total packets discarded, discarded and on which this block therefore depends.
   However
   However, the metric in [DISCARD] [RFC7002] may be used independently of the
   metrics in this block.

   This block provides information on transient IP problems.  Burst/Gap  Burst/gap
   metrics are typically used in cumulative reports, however reports; however, they also
   may be used in interval reports (see the Interval Metric flag in
   section
   Section 3.2).  The burstiness of packet discard affects user
   experience, may influence any sender strategies to mitigate the
   problem, and may also have diagnostic value.

   The metric belongs to the class of transport-related end system end-system
   metrics defined in [RFC6792].

   The definitions of Burst, Gap, Loss "burst", "gap", "loss", and Discard "discard" are
   consistent with the definitions in [RFC3611].  To accommodate the
   range of jitter buffer algorithms and packet discard logic that may
   be used by implementors, the method used to distinguish between
   bursts and gaps shall use an equivalent method to that defined in the section
   Section 4.7.2 of [RFC3611].  Note that Reporting reporting the specific jitter
   buffer algorithms and/or packet discard logic is out of the scope of
   this document.

1.2.  RTCP and RTCP XR Extended Reports

   The use of RTCP for reporting is defined in [RFC3550].  [RFC3611]
   defined an extensible structure for reporting using an RTCP Extended
   Report (XR).  This document defines a new Extended Report block for
   use with [RFC3550] and [RFC3611].

1.3.  Performance Metrics Framework

   The Performance Metrics Framework [RFC6390] provides guidance on the
   definition and specification of performance metrics.  The RTP
   Monitoring Architectures Framework [RFC6792] provides guideline guidelines for reporting
   block format using RTCP XR.  The metrics block described in this
   document are is in accordance with the guidelines in [RFC6390] and
   [RFC6792].

1.4.  Applicability

   These metrics are applicable to a range of RTP applications which that
   contain de-jitter buffers [RFC5481] at the receiving end to smooth
   variation in packet arriving packet-arrival time and don't use stream repair means,
   e.g., Forward Error Correction (FEC) [RFC5109] and/or retransmission
   [RFC4588].

2.  Terminology

2.1.  Standards Language

   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 [RFC2119].

   In addition, the following terms are defined:

   Received, Lost Lost, and Discarded

      A packet shall be regarded as lost "lost" if it fails to arrive within
      an implementation-specific time window.  A packet that arrives
      within this time window but is either too early to be played out or out, too
      late to be played out out, or thrown away before playout due to packet
      duplication or redundancy shall be regarded 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 higher-
      layer decoder, e.g., due to a decoding error.  A packet shall be
      classified as one of received (or OK), discarded discarded, or lost.  The
      metric "cumulative number of packets lost" defined in [RFC3550]
      reports a count of packets lost from the media stream (single SSRC
      synchronization source (SSRC) within a single RTP session).  Similarly
      Similarly, the metric "number of packets discarded" defined in [DISCARD]
      [RFC7002] reports a count of packets discarded from the media
      stream (single SSRC within a single RTP session) arriving at the
      receiver.  Another metric metric, defined in
      [RFC5725] [RFC5725], is available to
      report on packets which that are not recovered by any repair techniques which
      that may be in use.  Note that the term discard "discard" defined here build
      builds on the Discard "discard" definition
      [RFC3611], in [RFC3611] but extend extends the
      concept to take into account the packet
      duplication, duplication and report reports
      different types of discard counts
      [DISCARD]. [RFC7002].

   Bursts and Gaps

      The terms Burst "burst" and Gap "gap" are used in a manner consistent with
      that of RTCP XR [RFC3611].  RTCP XR views a 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 over 5 percent discard rate), and gaps, which are
      periods during which discarded packets are infrequent and hence
      quality is generally acceptable.

3.  Burst/Gap Discard Metrics Block

   Metrics in this block report on Burst/Gap Discard burst/gap discard in the stream
   arriving at the RTP system.  The measurement  Measurements of these metrics are made
   at the receiving end of the RTP stream.  Instances of this metrics
   block refer by Synchronization use the synchronization source (SSRC) to refer to the separate
   auxiliary Measurement Information Block [RFC6776] [RFC6776], which describes
   measurement periods in use (see RFC6776 section [RFC6776], 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.

3.1.  Report Block Structure

   The structure of the 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=NBGD     BT=20     | I |   resv.   resv    |      block length      Block Length = 3         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        SSRC of Source                         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   Threshold   |         Packets Discarded in Bursts           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |       Total Packets expected Expected in Bursts        |   Reserved.   Reserved    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                     Figure 1: Report Block Structure

3.2.  Definition of Fields in Burst/Gap Discard Report Metrics Block

   Block type Type (BT): 8 bits

      A Burst/Gap Discard Report Metrics Block is identified by the constant
      NBGD.

      [Note to RFC Editor: please replace NBGD with the IANA provided
      RTCP XR block type for this block.]
      20.

   Interval Metric flag (I): 2 bits

      This field is used to indicate whether the Burst/Gap Discard burst/gap discard
      metrics are Sampled, Interval Interval, or Cumulative metrics [RFC6792]:

         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.

         I=01: Sampled Value - the reported value is a sampled
         instantaneous value.

      In this document, Burst/Gap Discard Metrics burst/gap discard metrics can only be measured
      over definite intervals, 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.

   Reserved (resv): 6 bits

      These bits are reserved.  They MUST be set to zero by senders and
      ignored by receivers (See RFC6709 section (see [RFC6709], Section 4.2).

   block length:

   Block Length: 16 bits

      The length of this report block in 32-bit words, minus one.  For
      the Burst/Gap discard block, Discard Metrics Block, the block length is equal to
      3.  The block MUST be discarded if the block length is set to a
      different value.

   SSRC of source: Source: 32 bits

      As defined in Section 4.1 of [RFC3611].

   Threshold: 8 bits

      The Threshold is equivalent to Gmin in [RFC3611], i.e. i.e., the number
      of successive packets that must not be discarded prior to and
      following a discard packet in order for this discarded packet to
      be regarded as part of a gap.  Note that the threshold Threshold is set in
      accordance with the Gmin Calculation calculation defined in section Section 4.7.2 of
      RFC3611.
      [RFC3611].

   Packets discarded Discarded in bursts: Bursts: 24 bits

      The total number of packets discarded during discard bursts.

      The measured value is 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.

   Total packets expected Packets Expected in bursts: Bursts: 24 bits

      The total number of packets expected during discarded discard bursts (that
      is, the sum of received packets and lost packets).

      The measured value is 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.

   Reserved (resv):

   Reserved: 8 bits

      These bits are reserved.  They MUST be set to zero by senders and
      ignored by receivers (See RFC6709 section [RFC6709], Section 4.2).

3.3.  Derived metrics based Metrics Based on reported metrics Reported Metrics

   The metrics described here are intended to be used in conjunction
   with information from the Measurement Information Block [RFC6776] and
   also with the metric "number of packets discarded" provided in the
   RTCP XR Discard Count Metrics Block [DISCARD]. [RFC7002].

   These metrics provide the following information relevant to
   statistical parameters, including:

   o  The fraction of packets discarded during bursts (burst discard
      rate (Burst Discard
      Rate in [SUMSTAT]), [RFC7004]), which can be calculated using the metric "
      Packets
      "Packets Discarded in Bursts " Bursts" and the metric " Total "Total Packets
      expected
      Expected in Bursts " Bursts" provided in the Burst/Gap Discard Metrics
      Block.

   o  The fraction of packets discarded during gaps (gap discard rate (Gap Discard Rate in
      [SUMSTAT]),
      [RFC7004]), which can be calculated using the metric " Packets "Packets
      Discarded in Bursts " Bursts" and the metric " Total "Total Packets expected Expected in
      Bursts "
      Bursts" provided in the Burst/Gap Discard Metrics Block.

   The details on calculation these parameters in the metrics are
   described in [SUMSTAT]. [RFC7004].

4.  Considerations for Voice-over-IP applications Applications

   This metrics block is applicable to a broad range of RTP
   applications.  Where the metric is used with a Voice over IP 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 over 5 percent discard rate), rate) 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 burst and Gap Duration gap duration shall
   be determined as if silence packets had been sent, i.e. i.e., a period of
   silence in excess of Gmin packets will terminate a burst condition.

   The recommended value for the threshold Gmin in [RFC3611] results in
   a Burst burst being a period of time during which the call quality is
   degraded to a similar extent to a typical pulse-code modulation(PCM) pulse code modulation (PCM)
   severely errored second.

5.  SDP Signaling

   [RFC3611] defines the use of SDP (Session Description Protocol)
   [RFC4566] for signaling the use of XR blocks.  XR blocks MAY be used
   without prior signaling.

5.1.  SDP rtcp-xr-attrib rtcp-xr Attribute Extension

   This section augments the SDP [RFC4566] attribute "rtcp-xr" defined
   in [RFC3611] by providing an additional value of "xr-format" to
   signal the use of the report block defined in this document.  The
   ABNF [RFC5234] syntax is as follows.

   xr-format =/ xr-bgd-block

   xr-bgd-block = "burst-gap-discard"

5.2.  Offer/Answer Usage

   When SDP is used in offer-answer Offer/Answer context, the SDP Offer/Answer usage
   defined in [RFC3611] for unilateral "rtcp-xr" attribute parameters
   applies.  For detailed usage in Offer/Answer for unilateral
   parameter,
   parameters, refer to section Section 5.2 of [RFC3611].

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
   [RFC3611].

6.1.  New RTCP XR Block Type value Value

   This document assigns the block type value NBGD 20 in the IANA " RTP "RTP
   Control Protocol Extended Reports (RTCP XR) Block Type Registry " Registry" to
   the "Burst/Gap Discard Metrics Block".

   [Note to RFC Editor: please replace NBGD with the IANA provided RTCP
   XR block type for this block.]

6.2.  New RTCP XR SDP Parameter

   This document also registers a new parameter "burst-gap-discard" in
   the "RTP Control Protocol Extended Reports (RTCP XR) Session
   Description Protocol (SDP) Parameters Registry".

6.3.  Contact information Information for registrations Registrations

   The contact information for the registrations is:

   Qin Wu (sunseawq@huawei.com)
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

7.  Security Considerations

   It is believed that this proposed RTCP XR report block introduces no new security
   considerations beyond those described in [RFC3611].  This block does
   not provide per-packet statistics statistics, so the risk to confidentiality
   documented in Section 7, paragraph 3 of [RFC3611] does not apply.

8.  Contributors

   Geoff Hunt wrote the initial draft of this document.

9.  Acknowledgments

   The authors gratefully acknowledge reviews and feedback provided by
   Bruce Adams, Philip Arden, Amit Arora, Claire Bi, Bob Biskner, Benoit
   Claise, Kevin Connor, Claus Dahm, Randy Ethier, Roni Even, Stephen
   Farrell, Jim Frauenthal, Albert Higashi, Tom Hock, Shane Holthaus,
   Paul Jones, Rajesh Kumar, Paul Kyzivat, Keith Lantz, Mohamed Mostafa,
   Amy Pendleton, Colin Perkins, Mike Ramalho, Ravi Raviraj, Dan
   Romascanu, Albrecht Schwarz, Tom Taylor, Hideaki Yamada, Paul
   Kyzivat,Claire Bi,Stephen Farrell, Benoit Claise and Dan Romascanu. Hideaki Yamada.

10.  References

10.1.  Normative References

   [DISCARD]  Wu, Q., "RTCP XR Report Block for Discard Count metric
              Reporting", ID draft-ietf-xrblock-rtcp-xr-discard-11,
              December 2012.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3550]  Schulzrinne, H., Casner, S., Frederick, R., and V.
              Jacobson, "RTP: A Transport Protocol for Real-Time
              Applications", STD 64, RFC 3550, July 2003.

   [RFC3611]  Friedman, T., Caceres, R., and A. Clark, "RTP Control
              Protocol Extended Reports (RTCP XR)", RFC 3611, November
              2003.

   [RFC4566]  Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
              Description Protocol", RFC 4566, July 2006.

   [RFC5234]  Crocker, D. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", STD 68, RFC 5234, January 2008.

   [RFC5725]  Begen, A., Hsu, D., and M. Lague, "Post-Repair Loss RLE
              Report Block Type for RTP Control Protocol (RTCP) Extended
              Reports (XRs)", RFC 5725, February 2020. 2010.

   [RFC6776]  Clark, A. and Q. Wu, Q., "Measurement Identity and information Information
              Reporting
              using SDES item Using a Source Description (SDES) Item and XR an
              RTCP Extended Report (XR) Block", RFC 6776, October 2012.

   [SUMSTAT]

   [RFC7002]  Clark, A., Zorn, G., "RTCP XR and Q. Wu, "RTP Control Protocol
              (RTCP) Extended Report (XR) for Discard Count Metric
              Reporting", RFC 7002, August 2013.

   [RFC7004]  Zorn, G., Schott, R., Wu, Q., Ed., and R. Huang, "RTP
              Control Protocol (RTCP) Extended Report (XR) Blocks for
              Summary Statistics Metrics Reporting", ID draft-ietf-xrblock-rtcp-xr-summary-stat-11,
              March RFC 7004, August
              2013.

10.2.  Informative References

   [RFC4588]  Rey, J., Leon, D., , Miyazaki, A., Varsa, V., and R.
              Hakenberg, "RTP Retransmission Payload Format", RFC 4588,
              July 2006.

   [RFC5109]  Li, A., "RTP Payload Format for Generic Forward Error
              Correction", RFC 5109, December 2007.

   [RFC5481]  Morton, A. and B. Claise, "Packet Delay Variation
              Applicability Statement", RFC 5481, March 2009.

   [RFC6390]  Clark, A. and B. Claise, "Framework "Guidelines for Considering New
              Performance Metric Development", BCP 170, RFC 6390,
              October 2011.

   [RFC6709]  Carpenter, B., Aboba, B., and S. Cheshire, "Design
              Considerations for Protocol Extensions", RFC 6709,
              September 2012.

   [RFC6792]  Wu, Q., Hunt, G., "Monitoring Architectures and P. Arden, "Guidelines for RTP", Use of the
              RTP Monitoring Framework", RFC 6792, November 2012.

Appendix A.  Metrics represented using RFC6390 Template

   RFC EDITOR NOTE: please change XXXX in [RFCXXXX] by Represented Using the new Template from RFC
   number, when assigned. 6390

   a.  Burst/Gap Discard Threshold in RTP Metric

       *  Metric Name: Threshold Burst/gap discard threshold in RTP

       *  Metric Description: The Threshold is equivalent to Gmin in
          [RFC3611], i.e. i.e., the number of successive packets that must
          not be discarded prior to and following a discard packet in
          order for this discarded packet to be regarded as part of a
          gap.

       *  Method of Measurement or Calculation: See section Section 3.2,
          Threshold definition [RFCXXXX]. definition.

       *  Units of Measurement: See section Section 3.2, Threshold definition
          [RFCXXXX]. definition.

       *  Measurement Point(s) with Potential Measurement Domain: See
          section
          Section 3, 1st paragraph [RFCXXXX]. paragraph.

       *  Measurement Timing: See section Section 3, 2nd paragraph [RFCXXXX] for
          measurement timing and section Section 3.2 [RFCXXXX] for Interval Metric flag.

       *  Use and applications: Applications: See section 1.4 [RFCXXXX]. Section 1.4.

       *  Reporting model: Model: See RFC3611. RFC 3611.

   b.  Packets discarded Discarded in bursts Bursts Metric

       *  Metric Name: RTP Packets packets discarded in bursts

       *  Metric Description: The total number of RTP packets discarded
          during discard bursts.

       *  Method of Measurement or Calculation: See section Section 3.2, Packets
          discarded
          Discarded in bursts definition [RFCXXXX]. Bursts definition.

       *  Units of Measurement: See section Section 3.2, Packets discarded Discarded in
          bursts definition [RFCXXXX].
          Bursts definition.

       *  Measurement Point(s) with Potential Measurement Domain: See
          section
          Section 3, 1st paragraph [RFCXXXX]. paragraph.

       *  Measurement Timing: See section Section 3, 2nd paragraph [RFCXXXX] for
          measurement timing and section Section 3.2 [RFCXXXX] for Interval Metric flag.

       *  Use and applications: Applications: See section 1.4 [RFCXXXX]. Section 1.4.

       *  Reporting model: Model: See RFC3611. RFC 3611.

   c.  Total packets expected Packets Expected in bursts Discard Bursts Metric

       *  Metric Name: Total RTP packets expected in discard bursts

       *  Metric Description: The total number of packets expected
          during discarded discard bursts (that is, the sum of received packets
          and lost packets).

       *  Method of Measurement or Calculation: See section Section 3.2, Total
          packets expected
          Packets Expected in bursts definition [RFCXXXX]. Bursts definition.

       *  Units of Measurement: See section Section 3.2, Total packets expected Packets Expected
          in bursts definition [RFCXXXX]. Bursts definition.

       *  Measurement Point(s) with Potential Measurement Domain: See
          section
          Section 3, 1st paragraph [RFCXXXX]. paragraph.

       *  Measurement Timing: See section Section 3, 2nd paragraph [RFCXXXX] for
          measurement timing and section Section 3.2 [RFCXXXX] for Interval Metric flag.

       *  Use and applications: Applications: See section 1.4 [RFCXXXX]. Section 1.4.

       *  Reporting model: Model: See RFC3611.

Appendix B.  Change Log

   Note to the RFC-Editor: please remove this section prior to
   publication as an RFC.

B.1.  draft-ietf-xrblock-rtcp-xr-burst-gap-discard-14

   The following are the major changes compared to previous version:

   o  Editorial changes to address comments raised in IESG review and
      other Directorate review.

B.2.  draft-ietf-xrblock-rtcp-xr-burst-gap-discard-13

   The following are the major changes compared to previous version:

   o  Additional editorial changes to Burst Gap discard draft to get in
      line with Burst Gap Loss draft.

B.3.  draft-ietf-xrblock-rtcp-xr-burst-gap-discard-12

   The following are the major changes compared to previous version:

   o  Similar changes to Burst Gap loss draft to get in line with Burst
      Gap Loss draft.

B.4.  draft-ietf-xrblock-rtcp-xr-burst-gap-discard-11

   The following are the major changes compared to previous version:

   o  Similar changes to Burst Gap loss draft to address IESG review
      comments apply to this document.

B.5.  draft-ietf-xrblock-rtcp-xr-burst-gap-discard-10

   The following are the major changes compared to previous version:

   o  Move RFC6709 as one informative reference. RFC 3611.

Authors' Addresses

   Alan Clark
   Telchemy Incorporated
   2905 Premiere Parkway, Suite 280
   Duluth, GA  30097
   USA

   Email:

   EMail: alan.d.clark@telchemy.com

   Rachel Huang
   Huawei Technologies Co., Ltd.
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   Email:

   EMail: Rachel@huawei.com

   Qin Wu (editor)
   Huawei
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   Email:

   EMail: sunseawq@huawei.com