draft-ietf-xrblock-rtcp-xr-burst-gap-discard-00.txt   draft-ietf-xrblock-rtcp-xr-burst-gap-discard-01.txt 
Audio/Video Transport Working Group G. Hunt Audio/Video Transport Working Group G. Hunt
Internet-Draft Unaffiliated Internet-Draft Unaffiliated
Intended status: Standards Track A. Clark Intended status: Standards Track A. Clark
Expires: April 19, 2012 Telchemy Expires: July 22, 2012 Telchemy
R. Huang, Ed. R. Huang
Q. Wu Q. Wu, Ed.
Huawei Huawei
October 17, 2011 January 19, 2012
RTCP XR Report Block for Burst/Gap Discard metric Reporting RTCP XR Report Block for Burst/Gap Discard metric Reporting
draft-ietf-xrblock-rtcp-xr-burst-gap-discard-00.txt draft-ietf-xrblock-rtcp-xr-burst-gap-discard-01.txt
Abstract Abstract
This document defines an RTCP XR Report Block that allows the This document defines an RTCP XR Report Block that allows the
reporting of Burst and Gap Discard metrics for use in a range of RTP reporting of Burst and Gap Discard metrics for use in a range of RTP
applications. applications.
Status of this Memo Status of this Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on April 19, 2012. This Internet-Draft will expire on July 22, 2012.
Copyright Notice Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
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the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
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1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Burst and Gap Discard Report Block . . . . . . . . . . . . 3 1.1. Burst and Gap Discard Report Block . . . . . . . . . . . . 3
1.2. RTCP and RTCP XR 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 . . . . . . . . . . . . . . . . . . . . . . 4 1.4. Applicability . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1. Standards Language . . . . . . . . . . . . . . . . . . . . 5 2.1. Standards Language . . . . . . . . . . . . . . . . . . . . 5
3. Burst/Gap Discard Block . . . . . . . . . . . . . . . . . . . 6 3. Burst/Gap Discard Block . . . . . . . . . . . . . . . . . . . 6
3.1. Report Block Structure . . . . . . . . . . . . . . . . . . 6 3.1. Report Block Structure . . . . . . . . . . . . . . . . . . 6
3.2. Definition of Fields in Burst/Gap Loss Report Block . . . 6 3.2. Definition of Fields in Burst/Gap Loss Report Block . . . 6
3.3. Derived metrics based on reported metrics . . . . . . . . 8 3.3. Derived metrics based on reported metrics . . . . . . . . 7
4. Considerations for Voice-over-IP applications . . . . . . . . 10 4. Considerations for Voice-over-IP applications . . . . . . . . 9
5. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 11 5. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 10
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
6.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 12 6.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 11
6.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 12 6.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 11
6.3. Contact information for registrations . . . . . . . . . . 12 6.3. Contact information for registrations . . . . . . . . . . 11
7. Security Considerations . . . . . . . . . . . . . . . . . . . 13 7. Security Considerations . . . . . . . . . . . . . . . . . . . 12
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 14 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 13
9. Changes from previous version . . . . . . . . . . . . . . . . 15 9. Changes from previous version . . . . . . . . . . . . . . . . 14
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
10.1. Normative References . . . . . . . . . . . . . . . . . . . 16 10.1. Normative References . . . . . . . . . . . . . . . . . . . 15
10.2. Informative References . . . . . . . . . . . . . . . . . . 16 10.2. Informative References . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction 1. Introduction
1.1. Burst and Gap Discard Report Block 1.1. Burst and Gap Discard Report Block
This draft defines a new block type to augment those defined in This draft 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
receiver due to jitter. The discards during discard bursts are receiver due to jitter. The discards during discard bursts are
reported, together with the number of bursts and additional data reported, together with the number of bursts and additional data
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1.2. RTCP and RTCP XR Reports 1.2. RTCP and RTCP XR 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 draft defines a new Extended Report block that Report (XR). This draft defines a new Extended Report block that
MUST be used as defined in [RFC3550] and [RFC3611]. MUST be used as defined in [RFC3550] and [RFC3611].
1.3. Performance Metrics Framework 1.3. Performance Metrics Framework
The Performance Metrics Framework [PMOLFRAME] provides guidance on The Performance Metrics Framework [RFC6390] provides guidance on the
the definition and specification of performance metrics. Metrics definition and specification of performance metrics. Metrics
described in this draft either reference external definitions or described in this draft either reference external definitions or
define metrics generally in accordance with the guidelines in define metrics generally in accordance with the guidelines in
[PMOLFRAME]. [RFC6390].
1.4. Applicability 1.4. Applicability
These metrics are applicable to a range of RTP applications. These metrics are applicable to a range of RTP applications.
2. Terminology 2. Terminology
2.1. Standards Language 2.1. Standards Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
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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 that
of RTCP XR [RFC3611]. RTCP XR views a RTP stream as being divided of RTCP XR [RFC3611]. RTCP XR views a RTP stream as being divided
into bursts, which are periods during which the loss rate is high into bursts, which are periods during which the loss rate is high
enough to cause noticeable quality degradation (generally over 5 enough to cause noticeable quality degradation (generally over 5
percent loss rate), and gaps, which are periods during which lost percent loss rate), and gaps, which are periods during which lost
packets are infrequent and hence quality is generally acceptable. packets are infrequent and hence quality is generally acceptable.
3. Burst/Gap Discard Block 3. Burst/Gap Discard Block
Metrics in this block report on Burst/Gap Loss in the stream arriving Metrics in this block report on Burst/Gap Discard in the stream
at the RTP system. arriving at the RTP system.
3.1. Report Block Structure 3.1. Report Block Structure
Delay metrics block Burst/Gap Discard metrics block
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BT=NBGD |I| resv. | block length = 5 | | BT=NBGD |I| resv. | block length = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of Source | | SSRC of Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Threshold | Sum of Burst Durations (ms) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Packets Discarded in Bursts | Total... | | Packets Discarded in Bursts | Total... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ...Packets expected in bursts | Number of bursts | Sum of| | ...Packets expected in bursts | Reserved. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ...Squares of Burst Durations (ms-squared) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Report Block Structure Figure 1: Report Block Structure
3.2. Definition of Fields in Burst/Gap Loss Report Block 3.2. Definition of Fields in Burst/Gap Loss Report Block
Block type (BT): 8 bits Block type (BT): 8 bits
A Burst/Gap Loss Report Block is identified by the constant NBGL. A Burst/Gap Discard Report Block is identified by the constant
NBGD.
[Note to RFC Editor: please replace NBGL with the IANA provided [Note to RFC Editor: please replace NBGD with the IANA provided
RTCP XR block type for this block.] RTCP XR block type for this block.]
Interval Metric flag (I): 1 bit Interval Metric flag (I): 1 bit
This field is used to indicate whether the Packet Delay Variation This field is used to indicate whether the Packet Delay Variation
metrics block is an Interval or a Cumulative report, that is, metrics block is an Interval or a Cumulative report, that is,
whether the reported values apply to the most recent measurement whether the reported values apply to the most recent measurement
interval duration between successive metrics reports (I=1) (the interval duration between successive metrics reports (I=1) (the
Interval Duration) or to the accumulation period characteristic of Interval Duration) or to the accumulation period characteristic of
cumulative measurements (I=0) (the Cumulative Duration). cumulative measurements (I=0) (the Cumulative Duration).
Reserved (resv): 7 bits Reserved (resv): 7 bits
These bits are reserved. They SHOULD be set to zero by senders These bits are reserved. They SHOULD be set to zero by senders
and MUST be ignored by receivers. and MUST be ignored by receivers.
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 Delay block, the block length is equal to 5. the Delay block, the block length is equal to 2.
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
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 frame in order for this lost frame to be regarded as part
of a gap.
Sum of Burst Durations (ms): 24 bits
The total duration of bursts of lost frames in the period of the
report (Interval or Cumulative).
If the measured value exceeds 0xFFFFFD, the value 0xFFFFFE SHOULD
be reported to indicate an over-range measurement. If the
measurement is unavailable, the value 0xFFFFFF SHOULD be reported.
Packets lost in bursts: 24 bits Packets lost in bursts: 24 bits
The total number of packets lost during loss bursts. The total number of packets lost during loss bursts.
If the measured value exceeds 0xFFFFFD, the value 0xFFFFFE SHOULD If the measured value exceeds 0xFFFFFD, the value 0xFFFFFE SHOULD
be reported to indicate an over-range measurement. If the be reported to indicate an over-range measurement. If the
measurement is unavailable, the value 0xFFFFFF SHOULD be reported. measurement is unavailable, the value 0xFFFFFF SHOULD be reported.
Total packets expected in bursts: 24 bits Total packets expected in bursts: 24 bits
The total number of packets expected during loss bursts (that is, The total number of packets expected during loss bursts (that is,
the sum of received packets and lost packets). the sum of received packets and lost packets).
If the measured value exceeds 0xFFFFFD, the value 0xFFFFFE SHOULD If the measured value exceeds 0xFFFFFD, the value 0xFFFFFE SHOULD
be reported to indicate an over-range measurement. If the be reported to indicate an over-range measurement. If the
measurement is unavailable, the value 0xFFFFFF SHOULD be reported. measurement is unavailable, the value 0xFFFFFF SHOULD be reported.
Number of bursts: 16 bits Reserved (resv): 16 bits
The number of bursts in the period of the report (Interval or
Cumulative).
If the measured value exceeds 0xFFFD, the value 0xFFFE SHOULD be
reported to indicate an over-range measurement. If the
measurement is unavailable, the value 0xFFFF SHOULD 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) over in the period of the report
(Interval or Cumulative). The units for this quantity are
milliseconds-squared.
If the measured value exceeds 0xFFFFFFFFD, the value 0xFFFFFFFFE These bits are reserved. They SHOULD be set to zero by senders
SHOULD be reported to indicate an over-range measurement. If the and MUST be ignored by receivers.
measurement is unavailable, the value 0xFFFFFFFFF SHOULD be
reported.
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 as described in The metrics described here are intended to be used as described in
this section, in conjunction with information from the Measurement this section, in conjunction with information from the Measurement
Information block (which MUST be present in the same RTCP packet as Information block [MEASID], discard block [DISCARD] (which MUST be
the Burst/Gap Loss block) and also with the metric "cumulative number present in the same RTCP packet as the Burst/Gap Discard block).
of packets lost" provided in standard RTCP [RFC3550].
These metrics provides information relevant to statistical
parameters, including:
o The fraction of packets discarded during bursts
o The fraction of packets discarded during gaps These metrics provides the following information relevant to
statistical parameters, including:
o burst duration mean o The fraction of packets discarded during bursts (burst discard
rate in [SUMSTAT])
o burst duration variance o The fraction of packets discarded during gaps (gap discard rate in
[SUMSTAT])
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 [SUMSTAT].
4. Considerations for Voice-over-IP applications 4. Considerations for Voice-over-IP applications
This metric block is applicable to a broad range of RTP applications. This metric block is applicable to a broad range of RTP applications.
Where the metric is used with a Voice-overIP (VoIP) application, the Where the metric is used with a Voice-overIP (VoIP) application, the
following considerations apply. following considerations apply.
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which are periods during which lost packets are infrequent and hence which are periods during which lost packets are infrequent and hence
call quality is generally acceptable. 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 frames had been sent, i.e. a period of be determined as if silence frames had been sent, i.e. a period of
silence in excess of Gmin frames MUST terminate a burst condition. silence in excess of Gmin frames MUST 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 PCM Severely Errored Second degraded to a similar extent to a typical PCM Severely Errored Second
[SDES]. [PSES].
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.
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.
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[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)", 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", July 2006.
10.2. Informative References 10.2. Informative References
[DISCARD] Hunt, G., "RTCP XR Report Block for Discard metric [DISCARD] Hunt, G., "RTCP XR Report Block for Discard metric
Reporting", ID draft-ietf-rtcp-xr-discard-02, May 2009. Reporting", ID draft-ietf-xrblock-rtcp-xr-discard-01,
December 2011.
[MEASID] Wu, Q., "Measurement Identity and information Reporting
using SDES item and XR Block",
ID draft-ietf-xrblock-rtcp-xr-meas-identity-01,
October 2011.
[MONARCH] Hunt, G., "Monitoring Architectures for RTP", [MONARCH] Hunt, G., "Monitoring Architectures for RTP",
ID draft-ietf-avtcore-monarch-04, August 2011. ID draft-ietf-avtcore-monarch-04, August 2011.
[PMOLFRAME] [PSES] "URL", http://www.its.bldrdoc.gov/projects/devglossary/
Clark, A. and B. Claise, "Framework for Performance Metric
Development", ID draft-ietf-pmol-metrics-framework-12,
July 2011.
[SDES] "", URL http://www.its.bldrdoc.gov/projects/devglossary/
_severely_errored_second.html, October 2011. _severely_errored_second.html, October 2011.
[RFC6390] Clark, A. and B. Claise, "Framework for Performance Metric
Development", RFC 6390, October 2011.
[SUMSTAT] Zorn, G., "RTCP XR for Summary Statistics Metrics [SUMSTAT] Zorn, G., "RTCP XR for Summary Statistics Metrics
Reporting", ID draft-zorn-xrblock-rtcp-xr-al-stat-03, Reporting", ID draft-zorn-xrblock-rtcp-xr-al-stat-03,
October 2011. October 2011.
Authors' Addresses Authors' Addresses
Geoff Hunt Geoff Hunt
Unaffiliated Unaffiliated
Email: r.geoff.hunt@gmail.com Email: r.geoff.hunt@gmail.com
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 (editor) 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 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
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