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rfc:rfc6958

Internet Engineering Task Force (IETF) A. Clark Request for Comments: 6958 Telchemy Category: Standards Track S. Zhang ISSN: 2070-1721 J. Zhao

                                                                 STTRI
                                                            Q. Wu, Ed.
                                                                Huawei
                                                              May 2013
     RTP Control Protocol (RTCP) Extended Report (XR) Block for
                  Burst/Gap Loss Metric Reporting

Abstract

 This document defines an RTP Control Protocol (RTCP) Extended Report
 (XR) Block that allows the reporting of burst and 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 5741.
 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/rfc6958.

Copyright Notice

 Copyright (c) 2013 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.

Clark, et al. Standards Track [Page 1] RFC 6958 RTCP XR Burst/Gap Loss May 2013

Table of Contents

 1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   1.1.  Burst/Gap Loss Metrics Block  . . . . . . . . . . . . . .   2
   1.2.  RTCP and RTCP XR Reports  . . . . . . . . . . . . . . . .   3
   1.3.  Performance Metrics Framework . . . . . . . . . . . . . .   3
   1.4.  Applicability . . . . . . . . . . . . . . . . . . . . . .   3
 2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
 3.  Burst/Gap Loss Metrics Block  . . . . . . . . . . . . . . . .   4
   3.1.  Report Block Structure  . . . . . . . . . . . . . . . . .   5
   3.2.  Definition of Fields in Burst/Gap Loss Metrics Block  . .   5
   3.3.  Derived Metrics Based on Reported Metrics . . . . . . . .   7
 4.  Considerations for Voice-over-IP Applications . . . . . . . .   8
 5.  SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . .   9
   5.1.  SDP rtcp-xr-attrib Attribute Extension  . . . . . . . . .   9
   5.2.  Offer/Answer Usage  . . . . . . . . . . . . . . . . . . .   9
 6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   6.1.  New RTCP XR Block Type Value  . . . . . . . . . . . . . .   9
   6.2.  New RTCP XR SDP Parameter . . . . . . . . . . . . . . . .   9
   6.3.  Contact Information for Registrations . . . . . . . . . .  10
 7.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
 8.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  10
 9.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  10
 10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
   10.1.  Normative References . . . . . . . . . . . . . . . . . .  11
   10.2.  Informative References . . . . . . . . . . . . . . . . .  11
 Appendix A.  Metrics Represented Using the Template from RFC 6390  13

1. Introduction

1.1. Burst/Gap Loss 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 lost by the
 network.  The losses during loss bursts are reported, together with
 the number of bursts and additional data, allowing the calculation of
 statistical parameters (mean and variance) of the distribution of
 burst lengths.  Some uses of these metrics depend on the availability
 of the metric "cumulative number of packets lost" from RTCP
 [RFC3550].
 This block provides information on transient IP problems.  Burst/gap
 metrics are typically used in Cumulative reports; however, they also
 may be used in Interval reports.  The burstiness of packet loss
 affects user experience, may influence any sender strategies to
 mitigate the problem, and may also have diagnostic value.

Clark, et al. Standards Track [Page 2] RFC 6958 RTCP XR Burst/Gap Loss May 2013

 The metric belongs to the class of transport-related end system
 metrics defined in [RFC6792].
 The definitions of "burst", "gap", "loss", and "discard" are
 consistent with 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 may be an equivalent method to that defined in [RFC3611].  The
 method used should produce the same result as that defined in
 [RFC3611] for conditions of burst packet loss but may produce
 different results for conditions of time-varying jitter.

1.2. RTCP and RTCP XR Reports

 The use of RTCP for reporting is defined in [RFC3550].  [RFC3611]
 defines an extensible structure for reporting by 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 "Guidelines
 for Use of the RTP Monitoring Framework" [RFC6792] provides
 guidelines for reporting block format using RTCP XR.  The Metrics
 Block described in this document is in accordance with the guidelines
 in [RFC6390] and [RFC6792].

1.4. Applicability

 These metrics are applicable to a range of RTP applications that
 contain jitter buffers and don't use stream repair means, e.g.,
 Forward Error Correction (FEC) [RFC5109] and/or retransmission
 [RFC4588].

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 [RFC2119].

Clark, et al. Standards Track [Page 3] RFC 6958 RTCP XR Burst/Gap Loss May 2013

 In addition, the following terms are defined:
 Received, Lost, and Discarded
    A packet shall be 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 or late to be played out or
    thrown away before playout due to packet duplication or redundancy
    shall be regarded as discarded.  A packet shall be classified as
    one of received (or OK), discarded, or lost.  The metric
    "cumulative number of packets lost" defined in [RFC3550] 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
    [DISCARD] reports a count of packets discarded from the media
    stream (single SSRC within single RTP session) arriving at the
    receiver.  The post-repair Loss RLE metric, which is defined in
    [RFC5725], can be used to report the number of packets that are
    not recovered by any repair techniques that are in use.
 Bursts and Gaps
    The terms "burst" and "gap" are used in a manner consistent with
    that of RTCP XR [RFC3611].  RTCP XR views an RTP stream as being
    divided into bursts, which are periods when the loss rate is high
    enough to cause noticeable quality degradation (generally over 5
    percent loss rate) and gaps, which are periods when lost packets
    are infrequent and hence quality is generally acceptable.

3. Burst/Gap Loss Metrics Block

 Metrics in this block report on burst/gap loss in the stream arriving
 at the RTP system.  The measurement of these metrics is made at the
 receiving end of the RTP stream.  Each instance of this Metrics Block
 refers by SSRC to a separate auxiliary Measurement Information Block
 [RFC6776], which describes the 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.

Clark, et al. Standards Track [Page 4] RFC 6958 RTCP XR Burst/Gap Loss May 2013

3.1. Report Block Structure

 The structure of the Burst/Gap Loss 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=20     | I |C|  resv.  |      Block Length = 5         |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                        SSRC of Source                         |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -+-+-+-+-+-+-+-+
    | Threshold     |         Sum of Burst Durations (ms)           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |            Packets Lost in Bursts             |    Total...   |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    | ...Packets Expected in Bursts |    Number of Bursts   | Sum of|
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                ...Squares of Burst Durations (ms-squared)     |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                   Figure 1: Report Block Structure

3.2. Definition of Fields in Burst/Gap Loss Metrics Block

 Block Type (BT): 8 bits
    A Burst/Gap Loss Metrics Block is identified by the constant 20.
 Interval Metric flag (I): 2 bits
    This field is used to indicate whether the burst/gap loss metrics
    are Sampled, Interval, or Cumulative metrics:
       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 loss 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.

Clark, et al. Standards Track [Page 5] RFC 6958 RTCP XR Burst/Gap Loss May 2013

  Loss and Discard Combination flag (C): 1 bit
    The 'C' flag is used to indicate whether the loss/discard report
    is combined with the burst/gap loss report in the same compound
    RTCP packet.  The value is set to '1' if the loss/discard report
    and the burst gap loss report are combined.  Otherwise, the value
    is set to '0'.  If the 'C' flag is set to '1' but the burst/gap
    discard was not sent, the receiver MUST discard the burst/gap
    loss.
 Reserved (resv.): 5 bits
    These bits are reserved.  They MUST be set to zero by senders and
    ignored by receivers (see [RFC6709], Section 4.2).
 Block Length: 16 bits
    The length of this report block in 32-bit words, minus one.  For
    the Burst/Gap Loss 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 4.1 of [RFC3611].
 Threshold: 8 bits
    The Threshold is equivalent to Gmin in [RFC3611], i.e., the number
    of successive packets that must be received prior to and following
    a lost packet in order for this lost packet to be regarded as part
    of a gap.  Note that the threshold is calculated 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 lost 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.

Clark, et al. Standards Track [Page 6] RFC 6958 RTCP XR Burst/Gap Loss May 2013

 Packets Lost in Bursts: 24 bits
    The total number of packets lost during loss bursts.
    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.
 Total Packets Expected in Bursts: 24 bits
    The total number of packets expected during loss bursts (that is,
    the sum of received packets and lost packets).
    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.
 Number of Bursts: 16 bits
    The number of 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.
 Sum of Squares of Burst Durations (ms-squared): 36 bits
    The sum of the squares of burst durations (where individual burst
    durations are expressed in ms) in the period of the report
    (Interval or Cumulative).  The units for this quantity are
    milliseconds-squared.
    The measured value is an unsigned value.  If the measured value
    exceeds 0xFFFFFFFFD, the value 0xFFFFFFFFE MUST be reported to
    indicate an over-range measurement.  If the measurement is
    unavailable, the value 0xFFFFFFFFF MUST be reported.

3.3. Derived Metrics Based on Reported Metrics

 The metrics described here are intended to be used as described in
 this section, in conjunction with information from the Measurement
 Information Block [RFC6776] and also with the metric "cumulative
 number of packets lost" provided in standard RTCP [RFC3550].

Clark, et al. Standards Track [Page 7] RFC 6958 RTCP XR Burst/Gap Loss May 2013

 These metrics provide information relevant to statistical parameters,
 including:
 o  the fraction of packets lost during bursts (i.e., Burst Loss Rate
    in [SUMSTAT]), which can be calculated using the metric "Packets
    Loss in Bursts" and the metric "Total Packets Expected in Bursts"
    provided in the Burst/Gap Loss Metrics Block.
 o  the fraction of packets lost during gaps (i.e., Gap Loss Rate in
    [SUMSTAT]), which can be calculated using the metric "Packets Loss
    in Bursts" and the metric "Total Packets Expected in Bursts"
    provided in the Burst/Gap Loss Metrics Block.
 o  burst duration mean [SUMSTAT], which can be calculated using the
    metric "Packets Loss in Bursts" and the metric "Total Packets
    Expected in Bursts" provided in the Burst/Gap Loss Metrics Block.
 o  burst duration variance [SUMSTAT], which can be calculated using
    the metric "Packets Loss in Bursts" and the metric "Total Packets
    Expected in Bursts" provided in the Burst/Gap Loss Metrics Block.
 The details on calculation of these parameters in the metrics are
 described in [SUMSTAT].

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
 when the loss rate is high enough to cause noticeable call quality
 degradation (generally over 5 percent loss rate), and gaps, which are
 periods when lost packets are infrequent and hence call quality is
 generally acceptable.
 If Voice Activity Detection is used, the Burst and Gap Durations
 shall be 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 [RFC3611] causes a
 burst during which the call quality is degraded to a similar extent
 as it would be during a typical Pulse Code Modulation (PCM) Severely
 Errored Second.

Clark, et al. Standards Track [Page 8] RFC 6958 RTCP XR Burst/Gap Loss May 2013

5. SDP Signaling

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

5.1. SDP rtcp-xr-attrib 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 below.
 xr-format =/ xr-bgl-block
 xr-bgl-block = "burst-gap-loss"

5.2. Offer/Answer Usage

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

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

6.2. New RTCP XR SDP Parameter

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

Clark, et al. Standards Track [Page 9] RFC 6958 RTCP XR Burst/Gap Loss May 2013

6.3. Contact Information for 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

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

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, Bob Biskner, Kevin Connor,
 Claus Dahm, Randy Ethier, Roni Even, Jim Frauenthal, Albert Higashi,
 Tom Hock, Shane Holthaus, Paul Jones, Rajesh Kumar, Keith Lantz,
 Mohamed Mostafa, Amy Pendleton, Colin Perkins, Mike Ramalho, Ravi
 Raviraj, Albrecht Schwarz, Tom Taylor, Hideaki Yamada, Adam Roach,
 Dan Romascanu, Chris Lonvick, Alfred C. Morton Jr., Pete Resnick, Ted
 Lemon, Stephen Farrell, Richard Barnes, and Benoit Claise.

Clark, et al. Standards Track [Page 10] RFC 6958 RTCP XR Burst/Gap Loss May 2013

10. References

10.1. Normative References

 [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 2010.

10.2. Informative References

 [DISCARD]  Clark, A., Huang, R., and Q. Wu, Ed., "RTP Control
            Protocol (RTCP) Extended Report (XR) Block for Discard
            Count metric Reporting", Work in Progress, April 2013.
 [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.
 [RFC6390]  Clark, A. and B. Claise, "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.

Clark, et al. Standards Track [Page 11] RFC 6958 RTCP XR Burst/Gap Loss May 2013

 [RFC6776]  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, October 2012.
 [RFC6792]  Wu, Q., Hunt, G., and P. Arden, "Guidelines for Use of the
            RTP Monitoring Framework", RFC 6792, November 2012.
 [SUMSTAT]  Zorn, G., Schott, R., Wu, Q., Ed., and R. Huang, "RTP
            Control Protocol (RTCP) Extended Report (XR) Blocks for
            Summary Statistics Metrics Reporting", Work in Progress,
            March 2013.

Clark, et al. Standards Track [Page 12] RFC 6958 RTCP XR Burst/Gap Loss May 2013

Appendix A. Metrics Represented Using the Template from RFC 6390

 The six metrics defined in this document are described below using
 the template from Section 5.4.4 of RFC 6390.
 a.  Threshold Metric
  • Metric Name: Threshold in RTP
  • Metric Description: The Threshold is equivalent to Gmin in

[RFC3611], i.e., the number of successive RTP packets that

        must be received prior to and following a lost RTP packet in
        order for this lost RTP packet to be regarded as part of a
        gap.
  • Method of Measurement or Calculation: See Section 3.2,

Threshold definition.

  • Units of Measurement: See Section 3.2, Threshold definition.
  • Measurement Point(s) with Potential Measurement Domain: See

Section 3, 1st paragraph.

  • Measurement Timing: See Section 3, 2nd paragraph for

measurement timing and Section 3.2 for Interval Metric flag.

  • Use and Applications: See Section 1.4.
  • Reporting Model: See RFC 3611.
 b.  Sum of Burst Durations Metric
  • Metric Name: Sum of Burst Durations in RTP
  • Metric Description: The total duration of bursts of lost 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, 1st paragraph.

  • Measurement Timing: See Section 3, 2nd paragraph for

measurement timing and Section 3.2 for Interval Metric flag.

Clark, et al. Standards Track [Page 13] RFC 6958 RTCP XR Burst/Gap Loss May 2013

  • Use and Applications: See Section 1.4.
  • Reporting Model: See RFC 3611.
 c.  Packets Lost in Bursts Metric
  • Metric Name: RTP Packets lost in bursts
  • Metric Description: The total number of RTP packets lost

during loss bursts.

  • Method of Measurement or Calculation: See Section 3.2, Packets

Lost in Bursts definition.

  • Units of Measurement: See Section 3.2, Packets lost in bursts

definition.

  • Measurement Point(s) with Potential Measurement Domain: See

Section 3, 1st paragraph.

  • Measurement Timing: See Section 3, 2nd paragraph for

measurement timing and Section 3.2 for Interval Metric flag.

  • Use and Applications: See Section 1.4.
  • Reporting Model: See RFC 3611.
 d.  Total Packets Expected in Bursts Metric
  • Metric Name: Total RTP packets expected in bursts
  • Metric Description: The total number of RTP packets expected

during loss bursts (that is, the sum of received RTP packets

        and lost RTP packets).
  • Method of Measurement or Calculation: See Section 3.2, Total

packets expected in bursts definition.

  • Units of Measurement: See Section 3.2, Total packets expected

in bursts definition.

  • Measurement Point(s) with Potential Measurement Domain: See

Section 3, 1st paragraph.

  • Measurement Timing: See Section 3, 2nd paragraph for

measurement timing and Section 3.2 for Interval Metric flag.

  • Use and Applications: See Section 1.4.

Clark, et al. Standards Track [Page 14] RFC 6958 RTCP XR Burst/Gap Loss May 2013

  • Reporting Model: See RFC 3611.
 e.  Number of Bursts Metric
  • Metric Name: Number of bursts in RTP
  • Metric Description: The total duration of bursts of lost 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, Number of bursts

definition.

  • Measurement Point(s) with Potential Measurement Domain: See

Section 3, 1st paragraph.

  • Measurement Timing: See Section 3, 2nd paragraph for

measurement timing and Section 3.2 for Interval Metric flag.

  • Use and Applications: See Section 1.4.
  • Reporting Model: See RFC 3611.
 f.  Sum of Squares of Burst Durations Metric
  • Metric Name: Sum of Squares of Burst Durations in RTP
  • Metric Description: The sum of the squares of burst durations

(where individual burst durations are expressed in ms) over in

        the period of the report.
  • Method of Measurement or Calculation: See Section 3.2, Sum of

Squares of Burst Durations definition.

  • Units of Measurement: See Section 3.2, Sum of Squares of Burst

Durations definition.

  • Measurement Point(s) with Potential Measurement Domain: See

Section 3, 1st paragraph.

  • Measurement Timing: See Section 3, 2nd paragraph for

measurement timing and Section 3.2 for Interval Metric flag.

  • Use and Applications: See Section 1.4.
  • Reporting Model: See RFC 3611.

Clark, et al. Standards Track [Page 15] RFC 6958 RTCP XR Burst/Gap Loss May 2013

Authors' Addresses

 Alan Clark
 Telchemy Incorporated
 2905 Premiere Parkway, Suite 280
 Duluth, GA  30097
 USA
 EMail: alan.d.clark@telchemy.com
 Sunshine Zhang
 Shanghai Research Institute of China Telecom Corporation Limited
 No. 1835, South Pudong Road
 Shanghai  200122
 China
 EMail: zhangyx@sttri.com.cn
 Jing Zhao
 Shanghai Research Institute of China Telecom Corporation Limited
 No. 1835, South Pudong Road
 Shanghai  200122
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Clark, et al. Standards Track [Page 16]

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