Audio/Video Transport Working Group G. Hunt
Internet-Draft Unaffiliated
Intended status: Standards Track A. Clark
Expires: November 10, 2012 Telchemy
V. Singh
Aalto University
Q. Wu
Huawei
May 9, 2012
RTCP XR Report Block for Jitter Buffer Metric Reporting
draft-ietf-xrblock-rtcp-xr-jb-00.txt
Abstract
This document defines an RTCP XR Report Block that allows the
reporting of Jitter Buffer metrics for a range of RTP applications.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Jitter Buffer Metrics Block . . . . . . . . . . . . . . . 3
1.2. RTCP and RTCP XR Reports . . . . . . . . . . . . . . . . . 3
1.3. Performance Metrics Framework . . . . . . . . . . . . . . 3
1.4. Applicability . . . . . . . . . . . . . . . . . . . . . . 3
2. Jitter Buffer Metrics Block . . . . . . . . . . . . . . . . . 4
2.1. Report Block Structure . . . . . . . . . . . . . . . . . . 4
2.2. Definition of Fields in Jitter Buffer Metrics Block . . . 4
3. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 7
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
4.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 8
4.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 8
4.3. Contact information for registrations . . . . . . . . . . 8
5. Security Considerations . . . . . . . . . . . . . . . . . . . 9
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.1. Normative References . . . . . . . . . . . . . . . . . . . 11
7.2. Informative References . . . . . . . . . . . . . . . . . . 11
Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 12
A.1. draft-ietf-xrblock-rtcp-xr-jb-00 . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13
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1. Introduction
1.1. Jitter Buffer Metrics Block
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 provides information on jitter buffer
configuration and performance.
The metric belongs to the class of transport-related terminal metrics
defined in [MONARCH] (work in progress).
Instances of this Metrics Block refer by SSRC to the separate
auxiliary Measurement Information block [MEASI] which contains
information such as the SSRC of the measured stream, and RTP sequence
numbers and time intervals indicating the span of the report.
1.2. RTCP and RTCP XR Reports
The use of RTCP for reporting is defined in [RFC3550]. [RFC3611]
defined an extensible structure for reporting using an RTCP Extended
Report (XR). This draft defines a new Extended Report block that
MUST be used as defined in [RFC3550] and [RFC3611].
1.3. Performance Metrics Framework
The Performance Metrics Framework [RFC6390] provides guidance on the
definition and specification of performance metrics. The RTP
Monitoring Architectures [MONARCH] provides guideline for reporting
block format using RTCP XR. Metrics described in this draft are in
accordance with the guidelines in [RFC6390][MONARCH].
1.4. Applicability
These metrics are applicable to a range of RTP applications.
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2. Jitter Buffer Metrics Block
This block describes the configuration and operating parameters of
the jitter buffer in the receiver of the RTP end system or RTP mixer
which sends the report. Instances of this Metrics Block refer by
SSRC to the separate auxiliary Measurement Information block [MEASI]
which contains measurement intervals. This metric block relies on
the measurement interval in the Measurement Information block
indicating the span of the report and should be sent in the same
compound RTCP packet as the measurement information block. If the
measurement interval is not received in the same compound RTCP packet
as this metric block, this metric block should be discarded.
2.1. Report Block Structure
JB Metrics Block
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BT=NJB | I |jb cfg |rsv| block length=3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| JB nominal | JB maximum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| JB high water mark | JB low water mark |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Report Block Structure
2.2. Definition of Fields in Jitter Buffer Metrics Block
Block type (BT): 8 bits
A Jitter Buffer Metrics Report Block is identified by the constant
NJB.
[Note to RFC Editor: please replace NJB with the IANA provided
RTCP XR block type for this block.]
Interval Metric flag (I): 2 bits
This field is used to indicate whether the Jitter Buffer metrics
are Sampled, Interval or Cumulative metrics, that is, whether the
reported values applies to the most recent measurement interval
duration between successive metrics reports (I=10) (the Interval
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Duration) or to the accumulation period characteristic of
cumulative measurements (I=11) (the Cumulative Duration) or is a
sampled instantaneous value (I=01) (Sampled Value).
Jitter Buffer Configuration (jb cfg): 4 bits
This field is used to identify the jitter buffer method in use at
the receiver, according to the following code:
bits 014-011
0 = Fixed jitter buffer
1 = Adaptive jitter buffer
Other values reserved
Reserved (resv): 2 bits
These bits are reserved. They SHOULD be set to zero by senders
and MUST be ignored by receivers.
block length: 16 bits
The length of this report block in 32-bit words, minus one. For
the Delay block, the block length is equal to 3.
jitter buffer nominal delay (JB nominal): 16 bits
This is the current nominal jitter buffer delay in milliseconds,
which corresponds to the nominal jitter buffer delay for packets
that arrive exactly on time. This parameter MUST be provided for
both fixed and adaptive jitter buffer implementations.
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.
jitter buffer maximum delay (JB maximum): 16 bits
This is the current maximum jitter buffer delay in milliseconds
which corresponds to the earliest arriving packet that would not
be discarded. In simple queue implementations this may correspond
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to the nominal size. In adaptive jitter buffer implementations,
this value may dynamically. This parameter MUST be provided for
both fixed and adaptive jitter buffer implementations.
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.
jitter buffer high water mark (JB high water mark): 16 bits
This is the highest value of the jitter buffer nominal delay which
occurred at any time during the reporting interval.
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.
jitter buffer low water mark (JB low water mark): 16 bits
This is the lowest value of the jitter buffer nominal delay which
occurred at any time during the reporting interval.
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.
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3. SDP Signaling
[RFC3611] defines the use of SDP (Session Description Protocol)
[RFC4566] for signaling the use of XR blocks. XR blocks MAY be used
without prior signaling.
This section augments the SDP [RFC4566] attribute "rtcp-xr" defined
in [RFC3611] by providing an additional value of "xr-format" to
signal the use of the report block defined in this document.
rtcp-xr-attrib = "a=" "rtcp-xr" ":" [xr-format *(SP xr-format)] CRLF
(defined in [RFC3611])
xr-format =/ xr-jb-block
xr-jb-block = "jitter-bfr"
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4. IANA Considerations
New block types for RTCP XR are subject to IANA registration. For
general guidelines on IANA considerations for RTCP XR, refer to
[RFC3611].
4.1. New RTCP XR Block Type value
This document assigns the block type value NJB in the IANA "RTCP XR
Block Type Registry" to the "JB Metrics Block".
[Note to RFC Editor: please replace NJB with the IANA provided RTCP
XR block type for this block.]
4.2. New RTCP XR SDP Parameter
This document also registers a new parameter "jitter-bfr" in the
"RTCP XR SDP Parameters Registry".
4.3. Contact information for registrations
The contact information for the registrations is:
Geoff Hunt (r.geoff.hunt@gmail.com)
Orion 2 PP3, Adastral Park, Martlesham Heath, Ipswich IP5 3RE, United
Kingdom
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5. Security Considerations
It is believed that this proposed RTCP XR report block introduces no
new security considerations beyond those described in [RFC3611].
This block does not provide per-packet statistics so the risk to
confidentiality documented in Section 7, paragraph 3 of [RFC3611]
does not apply.
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6. Acknowledgments
The authors gratefully acknowledge the comments and contributions
made by Bruce Adams, Philip Arden, Amit Arora, Bob Biskner, Kevin
Connor, Claus Dahm, Randy Ethier, Roni Even, Jim Frauenthal, Albert
Higashi, Tom Hock, Shane Holthaus, Paul Jones, Rajesh Kumar, Keith
Lantz, Mohamed Mostafa, Amy Pendleton, Colin Perkins, Mike Ramalho,
Ravi Raviraj, Albrecht Schwarz, Tom Taylor, and Hideaki Yamada.
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7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", March 1997.
[RFC3550] Schulzrinne, H., "RTP: A Transport Protocol for Real-Time
Applications", RFC 3550, July 2003.
[RFC3611] Friedman, T., Caceres, R., and A. Clark, "RTP Control
Protocol Extended Reports (RTCP XR)", November 2003.
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
Description Protocol", July 2006.
7.2. Informative References
[MEASI] Hunt, G., "Measurement Identity and information Reporting
using SDES item and XR Block",
ID draft-ietf-xrblock-rtcp-xr-meas-identity-06,
April 2012.
[MONARCH] Hunt, G., "Monitoring Architectures for RTP",
ID draft-ietf-avtcore-monarch-12, April 2012.
[RFC6390] Clark, A. and B. Claise, "Framework for Performance Metric
Development", RFC 6390, October 2011.
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Appendix A. Change Log
Note to the RFC-Editor: please remove this section prior to
publication as an RFC.
A.1. draft-ietf-xrblock-rtcp-xr-jb-00
The following are the major changes to previous version :
o Boilerplate updates.
o references updates
o allocate 32 bit field in report block for SSRC
o Other editorial changes to get alignment with MONARCH draft.
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Authors' Addresses
Geoff Hunt
Unaffiliated
Email: r.geoff.hunt@gmail.com
Alan Clark
Telchemy Incorporated
2905 Premiere Parkway, Suite 280
Duluth, GA 30097
USA
Email: alan.d.clark@telchemy.com
Varun Singh
Aalto University
Otakaari 5 A
Espoo FIN 02150
Finland
Email: vsingh.ietf@gmail.com
Qin Wu
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: sunseawq@huawei.com
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