draft-ietf-xrblock-rtcp-xr-burst-gap-discard-14.txt   rfc7003.txt 
Audio/Video Transport Working Group A. Clark Internet Engineering Task Force (IETF) A. Clark
Internet-Draft Telchemy Request for Comments: 7003 Telchemy
Intended status: Standards Track R. Huang Category: Standards Track R. Huang
Expires: October 28, 2013 Q. Wu, Ed. ISSN: 2070-1721 Q. Wu, Ed.
Huawei Huawei
April 26, 2013 September 2013
RTP Control Protocol(RTCP) Extended Report (XR) Block for Burst/Gap RTP Control Protocol (RTCP) Extended Report (XR) Block
Discard metric Reporting for Burst/Gap Discard Metric Reporting
draft-ietf-xrblock-rtcp-xr-burst-gap-discard-14.txt
Abstract Abstract
This document defines an RTP Control Protocol(RTCP) Extended Report This document defines an RTP Control Protocol (RTCP) Extended Report
(XR) Block that allows the reporting of Burst and Gap Discard metrics (XR) block that allows the reporting of burst and gap discard metrics
for use in a range of RTP applications. for use in a range of RTP applications.
Status of this Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering This is an Internet Standards Track document.
Task Force (IETF). Note that other groups may also distribute
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and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
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Internet Standards is available in Section 2 of RFC 5741.
This Internet-Draft will expire on October 28, 2013. 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/rfc7003.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction ....................................................2
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Burst/Gap Discard Metrics Block ............................2
1.1. Burst and Gap Discard Report Block . . . . . . . . . . . . 3 1.2. RTCP and RTCP Extended Reports .............................3
1.2. RTCP and RTCP XR Reports . . . . . . . . . . . . . . . . . 3 1.3. Performance Metrics Framework ..............................3
1.3. Performance Metrics Framework . . . . . . . . . . . . . . 3 1.4. Applicability ..............................................3
1.4. Applicability . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology .....................................................3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Burst/Gap Discard Metrics Block .................................4
2.1. Standards Language . . . . . . . . . . . . . . . . . . . . 5 3.1. Report Block Structure .....................................5
3. Burst/Gap Discard Block . . . . . . . . . . . . . . . . . . . 6 3.2. Definition of Fields in Burst/Gap Discard Metrics Block ....5
3.1. Report Block Structure . . . . . . . . . . . . . . . . . . 6 3.3. Derived Metrics Based on Reported Metrics ..................7
3.2. Definition of Fields in Burst/Gap Discard Report Block . . 6 4. Considerations for Voice-over-IP Applications ...................7
3.3. Derived metrics based on reported metrics . . . . . . . . 8 5. SDP Signaling ...................................................8
4. Considerations for Voice-over-IP applications . . . . . . . . 10 5.1. SDP rtcp-xr Attribute Extension ............................8
5. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 11 5.2. Offer/Answer Usage .........................................8
5.1. SDP rtcp-xr-attrib Attribute Extension . . . . . . . . . . 11 6. IANA Considerations .............................................8
5.2. Offer/Answer Usage . . . . . . . . . . . . . . . . . . . . 11 6.1. New RTCP XR Block Type Value ...............................8
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 6.2. New RTCP XR SDP Parameter ..................................9
6.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 12 6.3. Contact Information for Registrations ......................9
6.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 12 7. Security Considerations .........................................9
6.3. Contact information for registrations . . . . . . . . . . 12 8. Contributors ....................................................9
7. Security Considerations . . . . . . . . . . . . . . . . . . . 13 9. Acknowledgments .................................................9
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 14 10. References ....................................................10
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 15 10.1. Normative References .....................................10
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16 10.2. Informative References ...................................10
10.1. Normative References . . . . . . . . . . . . . . . . . . . 16 Appendix A. Metrics Represented Using the Template from RFC 6390..12
10.2. Informative References . . . . . . . . . . . . . . . . . . 16
Appendix A. Metrics represented using RFC6390 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
1. Introduction 1. Introduction
1.1. Burst and Gap Discard Report Block 1.1. Burst/Gap Discard Metrics Block
This document defines a new block type to augment those defined in 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 [RFC3611] for use in a range of RTP applications. The new block type
supports the reporting of the proportion of packets discarded by the supports the reporting of the proportion of packets discarded by the
jitter buffer at the receiver, using packet discard logic according jitter buffer at the receiver, using packet discard logic according
to the jitter buffer algorithms. The discards during discard bursts to the jitter buffer algorithms. The discards during discard bursts
are reported, together with the number of bursts. This block is are reported, together with the number of bursts. This block is
intended to be used in conjunction with [DISCARD] which provides the intended to be used in conjunction with [RFC7002], which provides the
total packets discarded, and on which this block therefore depends. total packets discarded and on which this block therefore depends.
However the metric in [DISCARD] may be used independently of the However, the metric in [RFC7002] may be used independently of the
metrics in this block. metrics in this block.
This block provides information on transient IP problems. Burst/Gap This block provides information on transient IP problems. Burst/gap
metrics are typically used in cumulative reports, however they also metrics are typically used in cumulative reports; however, they also
may be used in interval reports (see the Interval Metric flag in may be used in interval reports (see the Interval Metric flag in
section 3.2). The burstiness of packet discard affects user Section 3.2). The burstiness of packet discard affects user
experience, may influence any sender strategies to mitigate the experience, may influence any sender strategies to mitigate the
problem, and may also have diagnostic value. problem, and may also have diagnostic value.
The metric belongs to the class of transport-related end system The metric belongs to the class of transport-related end-system
metrics defined in [RFC6792]. metrics defined in [RFC6792].
The definitions of Burst, Gap, Loss and Discard are consistent with The definitions of "burst", "gap", "loss", and "discard" are
definitions in [RFC3611]. To accommodate the range of jitter buffer consistent with the definitions in [RFC3611]. To accommodate the
algorithms and packet discard logic that may be used by implementors, range of jitter buffer algorithms and packet discard logic that may
the method used to distinguish between bursts and gaps shall use an be used by implementors, the method used to distinguish between
equivalent method to that defined in the section 4.7.2 of [RFC3611]. bursts and gaps shall use an equivalent method to that defined in
Note that Reporting the specific jitter buffer algorithms and/or Section 4.7.2 of [RFC3611]. Note that reporting the specific jitter
packet discard logic is out of scope of this document. buffer algorithms and/or packet discard logic is out of the scope of
this document.
1.2. RTCP and RTCP XR Reports 1.2. RTCP and RTCP Extended Reports
The use of RTCP for reporting is defined in [RFC3550]. [RFC3611] The use of RTCP for reporting is defined in [RFC3550]. [RFC3611]
defined an extensible structure for reporting using an RTCP Extended defined an extensible structure for reporting using an RTCP Extended
Report (XR). This document defines a new Extended Report block for Report (XR). This document defines a new Extended Report block for
use with [RFC3550] and [RFC3611]. use with [RFC3550] and [RFC3611].
1.3. Performance Metrics Framework 1.3. Performance Metrics Framework
The Performance Metrics Framework [RFC6390] provides guidance on the The Performance Metrics Framework [RFC6390] provides guidance on the
definition and specification of performance metrics. The RTP definition and specification of performance metrics. The RTP
Monitoring Architectures [RFC6792] provides guideline for reporting Monitoring Framework [RFC6792] provides guidelines for reporting
block format using RTCP XR. The metrics block described in this block format using RTCP XR. The metrics block described in this
document are in accordance with the guidelines in [RFC6390] and document is in accordance with the guidelines in [RFC6390] and
[RFC6792]. [RFC6792].
1.4. Applicability 1.4. Applicability
These metrics are applicable to a range of RTP applications which These metrics are applicable to a range of RTP applications that
contain de-jitter buffers [RFC5481] at the receiving end to smooth contain de-jitter buffers [RFC5481] at the receiving end to smooth
variation in packet arriving time and don't use stream repair means, variation in packet-arrival time and don't use stream repair means,
e.g., Forward Error Correction (FEC) [RFC5109] and/or retransmission e.g., Forward Error Correction (FEC) [RFC5109] and/or retransmission
[RFC4588]. [RFC4588].
2. Terminology 2. Terminology
2.1. Standards Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
In addition, the following terms are defined: In addition, the following terms are defined:
Received, Lost and Discarded Received, Lost, and Discarded
A packet shall be regarded as lost if it fails to arrive within an A packet shall be regarded as "lost" if it fails to arrive within
implementation-specific time window. A packet that arrives within an implementation-specific time window. A packet that arrives
this time window but is either too early to be played out or too 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 late to be played out, or thrown away before playout due to packet
duplication or redundancy shall be regarded as discarded. A duplication or redundancy shall be regarded as discarded. A
packet shall not be regarded as discarded if it arrives within packet shall not be regarded as discarded if it arrives within
this time window but is dropped during decoding by some higher this time window but is dropped during decoding by some higher-
layer decoder, e.g., due to a decoding error. A packet shall be layer decoder, e.g., due to a decoding error. A packet shall be
classified as one of received (or OK), discarded or lost. The classified as one of received (or OK), discarded, or lost. The
metric "cumulative number of packets lost" defined in [RFC3550] metric "cumulative number of packets lost" defined in [RFC3550]
reports a count of packets lost from the media stream (single SSRC reports a count of packets lost from the media stream (single
within single RTP session). Similarly the metric "number of synchronization source (SSRC) within a single RTP session).
packets discarded" defined in [DISCARD] reports a count of packets Similarly, the metric "number of packets discarded" defined in
discarded from the media stream (single SSRC within single RTP [RFC7002] reports a count of packets discarded from the media
session) arriving at the receiver. Another metric defined in stream (single SSRC within a single RTP session) arriving at the
[RFC5725] is available to report on packets which are not receiver. Another metric, defined in [RFC5725], is available to
recovered by any repair techniques which may be in use. Note that report on packets that are not recovered by any repair techniques
the term discard defined here build on the Discard definition that may be in use. Note that the term "discard" defined here
[RFC3611], but extend the concept to take into account the packet builds on the "discard" definition in [RFC3611] but extends the
duplication, and report different types of discard counts concept to take into account packet duplication and reports
[DISCARD]. different types of discard counts [RFC7002].
Bursts and Gaps Bursts and Gaps
The terms Burst and Gap are used in a manner consistent with that The terms "burst" and "gap" are used in a manner consistent with
of RTCP XR [RFC3611]. RTCP XR views a RTP stream as being divided that of RTCP XR [RFC3611]. RTCP XR views an RTP stream as being
into bursts, which are periods during which the discard rate is divided into bursts, which are periods during which the discard
high enough to cause noticeable quality degradation (generally rate is high enough to cause noticeable quality degradation
over 5 percent discard rate), and gaps, which are periods during (generally over 5 percent discard rate), and gaps, which are
which discarded packets are infrequent and hence quality is periods during which discarded packets are infrequent and hence
generally acceptable. quality is generally acceptable.
3. Burst/Gap Discard Block 3. Burst/Gap Discard Metrics Block
Metrics in this block report on Burst/Gap Discard in the stream Metrics in this block report on burst/gap discard in the stream
arriving at the RTP system. The measurement of these metrics are arriving at the RTP system. Measurements of these metrics are made
made at the receiving end of the RTP stream. Instances of this at the receiving end of the RTP stream. Instances of this metrics
metrics block refer by Synchronization source (SSRC) to the separate block use the synchronization source (SSRC) to refer to the separate
auxiliary Measurement Information Block [RFC6776] which describes auxiliary Measurement Information Block [RFC6776], which describes
measurement periods in use (see RFC6776 section 4.2). measurement periods in use (see [RFC6776], Section 4.2).
This metrics block relies on the measurement period in the This metrics block relies on the measurement period in the
Measurement Information Block indicating the span of the report. Measurement Information Block indicating the span of the report.
Senders MUST send this block in the same compound RTCP packet as the Senders MUST send this block in the same compound RTCP packet as the
Measurement Information Block. Receivers MUST verify that the Measurement Information Block. Receivers MUST verify that the
measurement period is received in the same compound RTCP packet as measurement period is received in the same compound RTCP packet as
this metrics block. If not, this metrics block MUST be discarded. this metrics block. If not, this metrics block MUST be discarded.
3.1. Report Block Structure 3.1. Report Block Structure
Burst/Gap Discard Metrics Block The structure of the Burst/Gap Discard Metrics Block is as follows.
0 1 2 3 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 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 | I | resv. | block length = 3 | | BT=20 | I | resv | Block Length = 3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of Source | | SSRC of Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Threshold | Packets Discarded in Bursts | | Threshold | Packets Discarded in Bursts |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Total Packets expected in Bursts | Reserved. | | Total Packets Expected in Bursts | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Report Block Structure Figure 1: Report Block Structure
3.2. Definition of Fields in Burst/Gap Discard Report Block 3.2. Definition of Fields in Burst/Gap Discard Metrics Block
Block type (BT): 8 bits
A Burst/Gap Discard Report Block is identified by the constant Block Type (BT): 8 bits
NBGD.
[Note to RFC Editor: please replace NBGD with the IANA provided A Burst/Gap Discard Metrics Block is identified by the constant
RTCP XR block type for this block.] 20.
Interval Metric flag (I): 2 bits Interval Metric flag (I): 2 bits
This field is used to indicate whether the Burst/Gap Discard This field is used to indicate whether the burst/gap discard
metrics are Sampled, Interval or Cumulative metrics [RFC6792]: metrics are Sampled, Interval, or Cumulative metrics [RFC6792]:
I=10: Interval Duration - the reported value applies to the I=10: Interval Duration - the reported value applies to the
most recent measurement interval duration between successive most recent measurement interval duration between successive
metrics reports. metrics reports.
I=11: Cumulative Duration - the reported value applies to the I=11: Cumulative Duration - the reported value applies to the
accumulation period characteristic of cumulative measurements. accumulation period characteristic of cumulative measurements.
I=01: Sampled Value - the reported value is a sampled I=01: Sampled Value - the reported value is a sampled
instantaneous value. instantaneous value.
In this document, Burst/Gap Discard Metrics can only be measured In this document, burst/gap discard metrics can only be measured
over definite intervals, and cannot be sampled. Also, the value 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 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 I=00 or I=01. If a block is received with I=00 or I=01, the
receiver MUST discard the block. receiver MUST discard the block.
Reserved (resv): 6 bits Reserved (resv): 6 bits
These bits are reserved. They MUST be set to zero by senders and These bits are reserved. They MUST be set to zero by senders and
ignored by receivers (See RFC6709 section 4.2). ignored by receivers (see [RFC6709], Section 4.2).
block length: 16 bits Block Length: 16 bits
The length of this report block in 32-bit words, minus one. For The length of this report block in 32-bit words, minus one. For
the Burst/Gap discard block, the block length is equal to 3. The the Burst/Gap Discard Metrics Block, the block length is equal to
block MUST be discarded if the block length is set to a different 3. The block MUST be discarded if the block length is set to a
value. different value.
SSRC of source: 32 bits SSRC of Source: 32 bits
As defined in Section 4.1 of [RFC3611]. As defined in Section 4.1 of [RFC3611].
Threshold: 8 bits Threshold: 8 bits
The Threshold is equivalent to Gmin in [RFC3611], i.e. the number The Threshold is equivalent to Gmin in [RFC3611], i.e., the number
of successive packets that must not be discarded prior to and of successive packets that must not be discarded prior to and
following a discard packet in order for this discarded packet to following a discard packet in order for this discarded packet to
be regarded as part of a gap. Note that the threshold is set in be regarded as part of a gap. Note that the Threshold is set in
accordance with Gmin Calculation defined in section 4.7.2 of accordance with the Gmin calculation defined in Section 4.7.2 of
RFC3611. [RFC3611].
Packets discarded in bursts: 24 bits Packets Discarded in Bursts: 24 bits
The total number of packets discarded during discard bursts. The total number of packets discarded during discard bursts.
The measured value is unsigned value. If the measured value The measured value is unsigned value. If the measured value
exceeds 0xFFFFFD, the value 0xFFFFFE MUST be reported to indicate exceeds 0xFFFFFD, the value 0xFFFFFE MUST be reported to indicate
an over-range measurement. If the measurement is unavailable, the an over-range measurement. If the measurement is unavailable, the
value 0xFFFFFF MUST be reported. value 0xFFFFFF MUST be reported.
Total packets expected in bursts: 24 bits Total Packets Expected in Bursts: 24 bits
The total number of packets expected during discarded bursts (that The total number of packets expected during discard bursts (that
is, the sum of received packets and lost packets). is, the sum of received packets and lost packets).
The measured value is unsigned value. If the measured value The measured value is unsigned value. If the measured value
exceeds 0xFFFFFD, the value 0xFFFFFE MUST be reported to indicate exceeds 0xFFFFFD, the value 0xFFFFFE MUST be reported to indicate
an over-range measurement. If the measurement is unavailable, the an over-range measurement. If the measurement is unavailable, the
value 0xFFFFFF MUST be reported. value 0xFFFFFF MUST be reported.
Reserved (resv): 8 bits Reserved: 8 bits
These bits are reserved. They MUST be set to zero by senders and These bits are reserved. They MUST be set to zero by senders and
ignored by receivers (See RFC6709 section 4.2). ignored by receivers (See [RFC6709], Section 4.2).
3.3. Derived metrics based on reported metrics 3.3. Derived Metrics Based on Reported Metrics
The metrics described here are intended to be used in conjunction The metrics described here are intended to be used in conjunction
with information from the Measurement Information Block [RFC6776] and with information from the Measurement Information Block [RFC6776] and
also with the metric "number of packets discarded" provided in the also with the metric "number of packets discarded" provided in the
RTCP XR Discard Count Block [DISCARD]. RTCP XR Discard Count Metrics Block [RFC7002].
These metrics provide the following information relevant to These metrics provide the following information relevant to
statistical parameters, including: statistical parameters, including:
o The fraction of packets discarded during bursts (burst discard o The fraction of packets discarded during bursts (Burst Discard
rate in [SUMSTAT]), which can be calculated using the metric " Rate in [RFC7004]), which can be calculated using the metric
Packets Discarded in Bursts " and the metric " Total Packets "Packets Discarded in Bursts" and the metric "Total Packets
expected in Bursts " provided in the Burst/Gap Discard Metrics Expected in Bursts" provided in the Burst/Gap Discard Metrics
Block. Block.
o The fraction of packets discarded during gaps (gap discard rate in o The fraction of packets discarded during gaps (Gap Discard Rate in
[SUMSTAT]), which can be calculated using the metric " Packets [RFC7004]), which can be calculated using the metric "Packets
Discarded in Bursts " and the metric " Total Packets expected in Discarded in Bursts" and the metric "Total Packets Expected in
Bursts " provided in the Burst/Gap Discard Metrics Block. Bursts" provided in the Burst/Gap Discard Metrics Block.
The details on calculation these parameters in the metrics are The details on calculation these parameters in the metrics are
described in [SUMSTAT]. described in [RFC7004].
4. Considerations for Voice-over-IP applications 4. Considerations for Voice-over-IP Applications
This metrics block is applicable to a broad range of RTP This metrics block is applicable to a broad range of RTP
applications. Where the metric is used with a Voice over IP (VoIP) applications. Where the metric is used with a Voice-over-IP (VoIP)
application and the stream repair means is not available, the application and the stream repair means is not available, the
following considerations apply. following considerations apply.
RTCP XR views a call as being divided into bursts, which are periods 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 during which the discard rate is high enough to cause noticeable call
quality degradation (generally over 5 percent discard rate), and quality degradation (generally over 5 percent discard rate) and gaps,
gaps, which are periods during which discarded packets are infrequent which are periods during which discarded packets are infrequent and
and hence call quality is generally acceptable. hence call quality is generally acceptable.
If voice activity detection is used, the Burst and Gap Duration shall If voice activity detection is used, the burst and gap duration shall
be determined as if silence packets had been sent, i.e. a period of 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. silence in excess of Gmin packets will terminate a burst condition.
The recommended value for the threshold Gmin in [RFC3611] results in The recommended value for the threshold Gmin in [RFC3611] results in
a Burst being a period of time during which the call quality is 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) degraded to a similar extent to a typical pulse code modulation (PCM)
severely errored second. severely errored second.
5. SDP Signaling 5. SDP Signaling
[RFC3611] defines the use of SDP (Session Description Protocol) [RFC3611] defines the use of SDP (Session Description Protocol)
[RFC4566] for signaling the use of XR blocks. XR blocks MAY be used [RFC4566] for signaling the use of XR blocks. XR blocks MAY be used
without prior signaling. without prior signaling.
5.1. SDP rtcp-xr-attrib Attribute Extension 5.1. SDP rtcp-xr Attribute Extension
This section augments the SDP [RFC4566] attribute "rtcp-xr" defined This section augments the SDP [RFC4566] attribute "rtcp-xr" defined
in [RFC3611] by providing an additional value of "xr-format" to in [RFC3611] by providing an additional value of "xr-format" to
signal the use of the report block defined in this document. signal the use of the report block defined in this document. The
ABNF [RFC5234] syntax is as follows.
xr-format =/ xr-bgd-block xr-format =/ xr-bgd-block
xr-bgd-block = "burst-gap-discard" xr-bgd-block = "burst-gap-discard"
5.2. Offer/Answer Usage 5.2. Offer/Answer Usage
When SDP is used in offer-answer context, the SDP Offer/Answer usage When SDP is used in Offer/Answer context, the SDP Offer/Answer usage
defined in [RFC3611] for unilateral "rtcp-xr" attribute parameters defined in [RFC3611] for unilateral "rtcp-xr" attribute parameters
applies. For detailed usage in Offer/Answer for unilateral applies. For detailed usage in Offer/Answer for unilateral
parameter, refer to section 5.2 of [RFC3611]. parameters, refer to Section 5.2 of [RFC3611].
6. IANA Considerations 6. IANA Considerations
New block types for RTCP XR are subject to IANA registration. For New block types for RTCP XR are subject to IANA registration. For
general guidelines on IANA considerations for RTCP XR, refer to general guidelines on IANA considerations for RTCP XR, refer to
[RFC3611]. [RFC3611].
6.1. New RTCP XR Block Type value 6.1. New RTCP XR Block Type Value
This document assigns the block type value NBGD in the IANA " RTP This document assigns the block type value 20 in the IANA "RTP
Control Protocol Extended Reports (RTCP XR) Block Type Registry " to Control Protocol Extended Reports (RTCP XR) Block Type Registry" to
the "Burst/Gap Discard Metrics Block". 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 6.2. New RTCP XR SDP Parameter
This document also registers a new parameter "burst-gap-discard" in This document also registers a new parameter "burst-gap-discard" in
the "RTP Control Protocol Extended Reports (RTCP XR) Session the "RTP Control Protocol Extended Reports (RTCP XR) Session
Description Protocol (SDP) Parameters Registry". Description Protocol (SDP) Parameters Registry".
6.3. Contact information for registrations 6.3. Contact Information for Registrations
The contact information for the registrations is: The contact information for the registrations is:
Qin Wu (sunseawq@huawei.com) Qin Wu (sunseawq@huawei.com)
101 Software Avenue, Yuhua District
101 Software Avenue, Yuhua District Nanjing, Jiangsu 210012
Nanjing, Jiangsu 210012 China
China
7. Security Considerations 7. Security Considerations
It is believed that this proposed RTCP XR report block introduces no It is believed that this RTCP XR block introduces no new security
new security considerations beyond those described in [RFC3611]. considerations beyond those described in [RFC3611]. This block does
This block does not provide per-packet statistics so the risk to not provide per-packet statistics, so the risk to confidentiality
confidentiality documented in Section 7, paragraph 3 of [RFC3611] documented in Section 7, paragraph 3 of [RFC3611] does not apply.
does not apply.
8. Contributors 8. Contributors
Geoff Hunt wrote the initial draft of this document. Geoff Hunt wrote the initial draft of this document.
9. Acknowledgments 9. Acknowledgments
The authors gratefully acknowledge reviews and feedback provided by The authors gratefully acknowledge reviews and feedback provided by
Bruce Adams, Philip Arden, Amit Arora, Bob Biskner, Kevin Connor, Bruce Adams, Philip Arden, Amit Arora, Claire Bi, Bob Biskner, Benoit
Claus Dahm, Randy Ethier, Roni Even, Jim Frauenthal, Albert Higashi, Claise, Kevin Connor, Claus Dahm, Randy Ethier, Roni Even, Stephen
Tom Hock, Shane Holthaus, Paul Jones, Rajesh Kumar, Keith Lantz, Farrell, Jim Frauenthal, Albert Higashi, Tom Hock, Shane Holthaus,
Mohamed Mostafa, Amy Pendleton, Colin Perkins, Mike Ramalho, Ravi Paul Jones, Rajesh Kumar, Paul Kyzivat, Keith Lantz, Mohamed Mostafa,
Raviraj, Albrecht Schwarz, Tom Taylor, Hideaki Yamada, Paul Amy Pendleton, Colin Perkins, Mike Ramalho, Ravi Raviraj, Dan
Kyzivat,Claire Bi,Stephen Farrell, Benoit Claise and Dan Romascanu. Romascanu, Albrecht Schwarz, Tom Taylor, and Hideaki Yamada.
10. References 10. References
10.1. Normative 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 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3550] Schulzrinne, H., "RTP: A Transport Protocol for Real-Time [RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.
Applications", RFC 3550, July 2003. 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 [RFC3611] Friedman, T., Caceres, R., and A. Clark, "RTP Control
Protocol Extended Reports (RTCP XR)", November 2003. Protocol Extended Reports (RTCP XR)", RFC 3611, November
2003.
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
Description Protocol", July 2006. 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 [RFC5725] Begen, A., Hsu, D., and M. Lague, "Post-Repair Loss RLE
Report Block Type for RTP Control Protocol (RTCP) Extended Report Block Type for RTP Control Protocol (RTCP) Extended
Reports (XRs)", RFC 5725, February 2020. Reports (XRs)", RFC 5725, February 2010.
[RFC6776] Wu, Q., "Measurement Identity and information Reporting [RFC6776] Clark, A. and Q. Wu, "Measurement Identity and Information
using SDES item and XR Block", RFC 6776, October 2012. Reporting Using a Source Description (SDES) Item and an
RTCP Extended Report (XR) Block", RFC 6776, October 2012.
[SUMSTAT] Zorn, G., "RTCP XR for Summary Statistics Metrics [RFC7002] Clark, A., Zorn, G., and Q. Wu, "RTP Control Protocol
Reporting", ID draft-ietf-xrblock-rtcp-xr-summary-stat-11, (RTCP) Extended Report (XR) for Discard Count Metric
March 2013. Reporting", RFC 7002, September 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", RFC 7004, September
2013.
10.2. Informative References 10.2. Informative References
[RFC4588] Rey, J., Leon, D., , A., Varsa, V., and R. Hakenberg, "RTP [RFC4588] Rey, J., Leon, D., Miyazaki, A., Varsa, V., and R.
Retransmission Payload Format", RFC 4588, July 2006. Hakenberg, "RTP Retransmission Payload Format", RFC 4588,
July 2006.
[RFC5109] Li, A., "RTP Payload Format for Generic Forward Error [RFC5109] Li, A., "RTP Payload Format for Generic Forward Error
Correction", RFC 5109, December 2007. Correction", RFC 5109, December 2007.
[RFC5481] Morton, A. and B. Claise, "Packet Delay Variation [RFC5481] Morton, A. and B. Claise, "Packet Delay Variation
Applicability Statement", RFC 5481, March 2009. Applicability Statement", RFC 5481, March 2009.
[RFC6390] Clark, A. and B. Claise, "Framework for Performance Metric [RFC6390] Clark, A. and B. Claise, "Guidelines for Considering New
Development", RFC 6390, October 2011. Performance Metric Development", BCP 170, RFC 6390,
October 2011.
[RFC6709] Carpenter, B., Aboba, B., and S. Cheshire, "Design [RFC6709] Carpenter, B., Aboba, B., and S. Cheshire, "Design
Considerations for Protocol Extensions", RFC 6709, Considerations for Protocol Extensions", RFC 6709,
September 2012. September 2012.
[RFC6792] Hunt, G., "Monitoring Architectures for RTP", RFC 6792, [RFC6792] Wu, Q., Hunt, G., and P. Arden, "Guidelines for Use of the
November 2012. RTP Monitoring Framework", RFC 6792, November 2012.
Appendix A. Metrics represented using RFC6390 Template
RFC EDITOR NOTE: please change XXXX in [RFCXXXX] by the new RFC Appendix A. Metrics Represented Using the Template from RFC 6390
number, when assigned.
a. Threshold Metric a. Burst/Gap Discard Threshold in RTP Metric
* Metric Name: Threshold in RTP * Metric Name: Burst/gap discard threshold in RTP
* Metric Description: The Threshold is equivalent to Gmin in * Metric Description: The Threshold is equivalent to Gmin in
[RFC3611], i.e. the number of successive packets that must not [RFC3611], i.e., the number of successive packets that must
be discarded prior to and following a discard packet in order not be discarded prior to and following a discard packet in
for this discarded packet to be regarded as part of a gap. order for this discarded packet to be regarded as part of a
gap.
* Method of Measurement or Calculation: See section 3.2, * Method of Measurement or Calculation: See Section 3.2,
Threshold definition [RFCXXXX]. Threshold definition.
* Units of Measurement: See section 3.2, Threshold definition * Units of Measurement: See Section 3.2, Threshold definition.
[RFCXXXX].
* Measurement Point(s) with Potential Measurement Domain: See * Measurement Point(s) with Potential Measurement Domain: See
section 3, 1st paragraph [RFCXXXX]. Section 3, 1st paragraph.
* Measurement Timing: See section 3, 2nd paragraph [RFCXXXX] for * Measurement Timing: See Section 3, 2nd paragraph for
measurement timing and section 3.2 [RFCXXXX] for Interval measurement timing and Section 3.2 for Interval Metric flag.
Metric flag.
* Use and applications: See section 1.4 [RFCXXXX]. * Use and Applications: See Section 1.4.
* Reporting model: See RFC3611. * Reporting Model: See RFC 3611.
b. Packets discarded in bursts Metric b. Packets Discarded in Bursts Metric
* Metric Name: RTP Packets discarded in bursts * Metric Name: RTP packets discarded in bursts
* Metric Description: The total number of RTP packets discarded * Metric Description: The total number of RTP packets discarded
during discard bursts. during discard bursts.
* Method of Measurement or Calculation: See section 3.2, Packets * Method of Measurement or Calculation: See Section 3.2, Packets
discarded in bursts definition [RFCXXXX]. Discarded in Bursts definition.
* Units of Measurement: See section 3.2, Packets discarded in * Units of Measurement: See Section 3.2, Packets Discarded in
bursts definition [RFCXXXX]. Bursts definition.
* Measurement Point(s) with Potential Measurement Domain: See * Measurement Point(s) with Potential Measurement Domain: See
section 3, 1st paragraph [RFCXXXX]. Section 3, 1st paragraph.
* Measurement Timing: See section 3, 2nd paragraph [RFCXXXX] for * Measurement Timing: See Section 3, 2nd paragraph for
measurement timing and section 3.2 [RFCXXXX] for Interval measurement timing and Section 3.2 for Interval Metric flag.
Metric flag.
* Use and applications: See section 1.4 [RFCXXXX]. * Use and Applications: See Section 1.4.
* Reporting model: See RFC3611. * Reporting Model: See RFC 3611.
c. Total packets expected in bursts Metric c. Total Packets Expected in Discard Bursts Metric
* Metric Name: Total RTP packets expected in bursts * Metric Name: Total RTP packets expected in discard bursts
* Metric Description: The total number of packets expected * Metric Description: The total number of packets expected
during discarded bursts (that is, the sum of received packets during discard bursts (that is, the sum of received packets
and lost packets). and lost packets).
* Method of Measurement or Calculation: See section 3.2, Total * Method of Measurement or Calculation: See Section 3.2, Total
packets expected in bursts definition [RFCXXXX]. Packets Expected in Bursts definition.
* Units of Measurement: See section 3.2, Total packets expected * Units of Measurement: See Section 3.2, Total Packets Expected
in bursts definition [RFCXXXX]. in Bursts definition.
* Measurement Point(s) with Potential Measurement Domain: See * Measurement Point(s) with Potential Measurement Domain: See
section 3, 1st paragraph [RFCXXXX]. Section 3, 1st paragraph.
* Measurement Timing: See section 3, 2nd paragraph [RFCXXXX] for
measurement timing and section 3.2 [RFCXXXX] for Interval
Metric flag.
* Use and applications: See section 1.4 [RFCXXXX].
* Reporting 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 * Measurement Timing: See Section 3, 2nd paragraph for
measurement timing and Section 3.2 for Interval Metric flag.
The following are the major changes compared to previous version: * Use and Applications: See Section 1.4.
o Move RFC6709 as one informative reference. * Reporting Model: See RFC 3611.
Authors' Addresses Authors' Addresses
Alan Clark Alan Clark
Telchemy Incorporated Telchemy Incorporated
2905 Premiere Parkway, Suite 280 2905 Premiere Parkway, Suite 280
Duluth, GA 30097 Duluth, GA 30097
USA USA
Email: alan.d.clark@telchemy.com EMail: alan.d.clark@telchemy.com
Rachel Huang Rachel Huang
Huawei Technologies Co., Ltd. Huawei Technologies Co., Ltd.
101 Software Avenue, Yuhua District 101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012 Nanjing, Jiangsu 210012
China China
Email: Rachel@huawei.com EMail: Rachel@huawei.com
Qin Wu (editor) Qin Wu (editor)
Huawei Huawei
101 Software Avenue, Yuhua District 101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012 Nanjing, Jiangsu 210012
China China
Email: sunseawq@huawei.com EMail: sunseawq@huawei.com
 End of changes. 109 change blocks. 
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