draft-ietf-xrblock-rtcp-xr-burst-gap-discard-02.txt   draft-ietf-xrblock-rtcp-xr-burst-gap-discard-03.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: July 23, 2012 Telchemy Expires: October 20, 2012 Telchemy
R. Huang R. Huang
Q. Wu, Ed. Q. Wu, Ed.
Huawei Huawei
January 20, 2012 April 18, 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-02.txt draft-ietf-xrblock-rtcp-xr-burst-gap-discard-03.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
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 23, 2012. This Internet-Draft will expire on October 20, 2012.
Copyright Notice Copyright Notice
Copyright (c) 2012 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
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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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 Discard Report Block . . 6
3.3. Derived metrics based on reported metrics . . . . . . . . 8 3.3. Derived metrics based on reported metrics . . . . . . . . 8
4. Considerations for Voice-over-IP applications . . . . . . . . 9 4. Considerations for Voice-over-IP applications . . . . . . . . 9
5. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 10 5. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 10
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
6.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 11 6.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 11
6.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 11 6.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 11
6.3. Contact information for registrations . . . . . . . . . . 11 6.3. Contact information for registrations . . . . . . . . . . 11
7. Security Considerations . . . . . . . . . . . . . . . . . . . 12 7. Security Considerations . . . . . . . . . . . . . . . . . . . 12
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 13 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 13
9. Changes from previous version . . . . . . . . . . . . . . . . 14 9. Changes from previous version . . . . . . . . . . . . . . . . 14
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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 an
implementation-specific time window. A packet that arrives within implementation-specific time window. A packet that arrives within
this time window but is too early or late to be played out shall this time window but is too early or late to be played out shall
be regarded as discarded. A packet shall be classified as one of be regarded as discarded. A packet shall be classified as one of
received (or OK), discarded or lost. received (or OK), discarded or lost.
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 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 discard rate is
enough to cause noticeable quality degradation (generally over 5 high enough to cause noticeable quality degradation (generally
percent loss rate), and gaps, which are periods during which lost over 5 percent discard rate), and gaps, which are periods during
packets are infrequent and hence quality is generally acceptable. which discarded 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 Discard in the stream Metrics in this block report on Burst/Gap Discard in the stream
arriving at the RTP system. arriving at the RTP system.
3.1. Report Block Structure 3.1. Report Block Structure
Burst/Gap Discard metrics block Burst/Gap Discard metrics block
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 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 Loss Report Block 3.2. Definition of Fields in Burst/Gap Discard Report Block
Block type (BT): 8 bits Block type (BT): 8 bits
A Burst/Gap Discard Report Block is identified by the constant A Burst/Gap Discard Report Block is identified by the constant
NBGD. NBGD.
[Note to RFC Editor: please replace NBGD 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
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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 3. the Delay block, the block length is equal to 3.
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 be received prior to and following of successive packets that must not be discarded prior to and
a lost packet in order for this lost packet to be regarded as part following a discard packet in order for this discarded packet to
of a gap. be regarded as part of a gap.
Packets lost in bursts: 24 bits Packets discarded in bursts: 24 bits
The total number of packets lost during loss bursts. The total number of packets discarded during discard 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 discarded bursts (that
the sum of received packets and lost packets). is, 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.
Reserved (resv): 8 bits Reserved (resv): 8 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.
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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.
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 loss 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 loss rate), and gaps, quality degradation (generally over 5 percent discard rate), and
which are periods during which lost packets are infrequent and hence gaps, which are periods during which discarded packets are infrequent
call quality is generally acceptable. and 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 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
[PSES]. [PSES].
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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-xrblock-rtcp-xr-discard-01, Reporting", ID draft-ietf-xrblock-rtcp-xr-discard-02,
December 2011. April 2012.
[MEASID] Wu, Q., "Measurement Identity and information Reporting [MEASID] Wu, Q., "Measurement Identity and information Reporting
using SDES item and XR Block", using SDES item and XR Block",
ID draft-ietf-xrblock-rtcp-xr-meas-identity-01, ID draft-ietf-xrblock-rtcp-xr-meas-identity-05,
October 2011. April 2012.
[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-12, April 2012.
[PSES] "URL", http://www.its.bldrdoc.gov/projects/devglossary/ [PSES] "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 [RFC6390] Clark, A. and B. Claise, "Framework for Performance Metric
Development", RFC 6390, October 2011. 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-05,
October 2011. February 2012.
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
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