draft-ietf-xrblock-rtcp-xr-burst-gap-loss-02.txt   draft-ietf-xrblock-rtcp-xr-burst-gap-loss-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: January 11, 2013 Telchemy Expires: January 31, 2013 Telchemy
S. Zhang, Ed. S. Zhang, Ed.
J. Zhao J. Zhao
STTRI STTRI
Q. Wu Q. Wu
Huawei Huawei
July 10, 2012 July 30, 2012
RTCP XR Report Block for Burst/Gap Loss metric Reporting RTCP XR Report Block for Burst/Gap Loss metric Reporting
draft-ietf-xrblock-rtcp-xr-burst-gap-loss-02.txt draft-ietf-xrblock-rtcp-xr-burst-gap-loss-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 Loss metrics for use in a range of RTP reporting of Burst and Gap Loss 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
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
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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 January 11, 2013. This Internet-Draft will expire on January 31, 2013.
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 Loss Report Block . . . . . . . . . . . . . 3 1.1. Burst and Gap Loss 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 Loss Block . . . . . . . . . . . . . . . . . . . . . 6 3. Burst/Gap Loss 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 . . . . . . . . 9
4. Considerations for Voice-over-IP applications . . . . . . . . 10 4. Considerations for Voice-over-IP applications . . . . . . . . 10
5. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 11 5. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 11
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
6.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 12 6.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 12
6.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 12 6.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 12
6.3. Contact information for registrations . . . . . . . . . . 12 6.3. Contact information for registrations . . . . . . . . . . 12
7. Security Considerations . . . . . . . . . . . . . . . . . . . 13 7. Security Considerations . . . . . . . . . . . . . . . . . . . 13
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 14 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 14
9. Changes from previous version . . . . . . . . . . . . . . . . 15 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16 9.1. Normative References . . . . . . . . . . . . . . . . . . . 15
10.1. Normative References . . . . . . . . . . . . . . . . . . . 16 9.2. Informative References . . . . . . . . . . . . . . . . . . 15
10.2. Informative References . . . . . . . . . . . . . . . . . . 16 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction 1. Introduction
1.1. Burst and Gap Loss Report Block 1.1. Burst and Gap Loss 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 lost by the supports the reporting of the proportion of packets lost by the
network. The losses during loss bursts are reported, together with network. The losses during loss bursts are reported, together with
the number of bursts and additional data allowing the calculation of the number of bursts and additional data allowing the calculation of
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of the metric "cumulative number of packets lost" from RTCP of the metric "cumulative number of packets lost" from RTCP
[RFC3550]. [RFC3550].
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 MAY be used metrics are typically used in Cumulative reports however MAY be used
in Interval reports. The burstiness of packet loss affects user in Interval reports. The burstiness of packet loss 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 terminal metrics The metric belongs to the class of transport-related terminal metrics
defined in [MONARCH] . defined in [MONARCH].
The definitions of Burst, Gap, Loss and Discard are consistent with The definitions of Burst, Gap, Loss and Discard are consistent with
definitions in [RFC3611]. To accommodate the range of jitter buffer definitions in [RFC3611]. To accommodate the range of jitter buffer
algorithms and packet discard logic that may be used by implementors, algorithms and packet discard logic that may be used by implementors,
the method used to distinguish between bursts and gaps may be an the method used to distinguish between bursts and gaps may be an
equivalent method to that defined in [RFC3611]. The method used equivalent method to that defined in [RFC3611]. The method used
SHOULD produce the same result as that defined in [RFC3611] for SHOULD produce the same result as that defined in [RFC3611] for
conditions of burst packet loss, but MAY produce different results conditions of burst packet loss, but MAY produce different results
for conditions of time varying jitter. for conditions of time varying jitter.
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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. 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
[RFC6390]. [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 which
don't use stream repair means.
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",
"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 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 or
be regarded as discarded. A packet shall be classified as one of thrown away before playout due to packet duplication or redundancy
received (or OK), discarded or lost. 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 SSRC within
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. Another metric defined in
[RFC5725] is available to report on packets which are not
recovered by any repair techniques which may be in use.
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 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.
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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 Loss Report Block is identified by the constant NBGL.
[Note to RFC Editor: please replace NBGL with the IANA provided [Note to RFC Editor: please replace NBGL with the IANA provided
RTCP XR block type for this block.] RTCP XR block type for this block.]
Interval Metric flag (I): 2 bit Interval Metric flag (I): 2 bits
This field is used to indicate whether the Burst/Gap Loss metrics This field is used to indicate whether the Burst/Gap Loss metrics
are Sampled, Interval or Cumulative metrics, that is, whether the are Sampled, Interval or Cumulative metrics, that is, whether the
reported values applies to the most recent measurement interval reported values applies to the most recent measurement interval
duration between successive metrics reports (I=10) (the Interval duration between successive metrics reports (I=10) (the Interval
Duration) or to the accumulation period characteristic of Duration) or to the accumulation period characteristic of
cumulative measurements (I=11) (the Cumulative Duration) or is a cumulative measurements (I=11) (the Cumulative Duration) or is a
sampled instantaneous value (I=01) (Sampled Value). sampled instantaneous value (I=01) (Sampled Value). In this
document, Burst/Gap Loss Metric is not measured at a particular
time instant but over one or several reporting intervals.
Therefore Burst/Gap Loss Metric MUST not be chosen as Sampled
Metric. In this document, Burst/Gap Loss Metric is not measured
at a particular time instant but over one or several reporting
intervals. Therefore Burst/Gap Loss Metric MUST NOT be chosen as
Sampled Metric.
Loss and Discard Combination flag (C): 1 bit Loss and Discard Combination flag (C): 1 bit
The 'C' flag is used to indicate whether combining loss/discard The 'C' flag is used to indicate whether combining loss/discard
report is needed. This field MUST be set to '1' if the burst gap report is needed. This field MUST be set to '1' if the burst gap
loss report is present in conjunction with the burst gap discard loss report is present in conjunction with the burst gap discard
report in the same compound RTCP packet and MUST be set to '0' report in the same compound RTCP packet and MUST be set to '0'
otherwise. If the burst gap discard is not sent with burst gap otherwise. If the burst gap discard is not sent with the burst
loss, then the receiver should discard burst gap loss with 'C' gap loss, then the receiver MUST discard the burst gap loss with
flag set to 1. If the 'C' flag is set to 0, then receiver should 'C' flag set to 1. If the 'C' flag is set to 0, then receiver
not discard burst gap loss metric block when burst gap discard is MUST NOT discard the burst gap loss metric block when the burst
not received. gap discard is not received.
Reserved (resv): 5 bits Reserved (resv): 5 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 Burst/Gap Loss block, the block length is equal to 5.
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 be received prior to and following
a lost packet in order for this lost packet to be regarded as part a lost packet in order for this lost packet to be regarded as part
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o burst duration mean [SUMSTAT] o burst duration mean [SUMSTAT]
o burst duration variance [SUMSTAT] o burst duration variance [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 and
following considerations apply. the stream repair means is not available, the 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 loss rate is high enough to cause noticeable call
quality degradation (generally over 5 percent loss rate), and gaps, quality degradation (generally over 5 percent loss rate), and gaps,
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 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 MUST terminate a burst condition. silence in excess of Gmin packets MUST terminate a burst condition.
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8. Contributors 8. Contributors
The authors gratefully acknowledge the comments and contributions The authors gratefully acknowledge the comments and contributions
made by Bruce Adams, Philip Arden, Amit Arora, Bob Biskner, Kevin made by Bruce Adams, Philip Arden, Amit Arora, Bob Biskner, Kevin
Connor, Claus Dahm, Randy Ethier, Roni Even, Jim Frauenthal, Albert Connor, Claus Dahm, Randy Ethier, Roni Even, Jim Frauenthal, Albert
Higashi, Tom Hock, Shane Holthaus, Paul Jones, Rajesh Kumar, Keith Higashi, Tom Hock, Shane Holthaus, Paul Jones, Rajesh Kumar, Keith
Lantz, Mohamed Mostafa, Amy Pendleton, Colin Perkins, Mike Ramalho, Lantz, Mohamed Mostafa, Amy Pendleton, Colin Perkins, Mike Ramalho,
Ravi Raviraj, Albrecht Schwarz, Tom Taylor, and Hideaki Yamada. Ravi Raviraj, Albrecht Schwarz, Tom Taylor, and Hideaki Yamada.
9. Changes from previous version 9. References
Changed BNF for SDP following Christian Groves' and Tom Taylor's
comments (4th and 5th May 2009), now aligned with RFC 5234 section
3.3 "Incremental Alternatives".
Updated references.
10. References
10.1. Normative References 9.1. Normative References
[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", March 1997.
[RFC3550] Schulzrinne, H., "RTP: A Transport Protocol for Real-Time [RFC3550] Schulzrinne, H., "RTP: A Transport Protocol for Real-Time
Applications", RFC 3550, July 2003. Applications", 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)", 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 [RFC5725] Begen, A., Hsu, D., and M. Lague, "Post-Repair Loss RLE
Report Block Type for RTP Control Protocol (RTCP) Extended
Reports (XRs)", RFC 5725, February 2020.
9.2. 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-05,
July 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-09, July 2012.
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.
[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, July 2011. Development", RFC 6390, July 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-06,
October 2011. July 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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