Network Working Group G. Zorn
Internet-Draft Network Zen
Intended status: Standards Track R. Schott
Expires: July 22, 2012 Deutsche Telekom
Q. Wu
R. Huang
Huawei
January 19, 2012
RTCP XR for Summary Statistics Metrics Reporting
draft-zorn-xrblock-rtcp-xr-al-stat-04
Abstract
This document defines three RTCP XR Report Blocks and associated SDP
parameters that allows the reporting of loss, duplication and discard
summary statistics metrics for use in a range of RTP applications.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Applicability . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Standards Language . . . . . . . . . . . . . . . . . . . . 4
3. Transport Layer Metrics . . . . . . . . . . . . . . . . . . . 4
3.1. Burst/Gap Loss Summsary Statistics Block . . . . . . . . . 4
3.1.1. Report Block Structure . . . . . . . . . . . . . . . . 5
3.1.2. Definition of Fields in Loss Summary Statistics
Block . . . . . . . . . . . . . . . . . . . . . . . . 5
3.2. Burst/Gap Discard Summary Statistics Block . . . . . . . . 7
3.2.1. Report Block Structure . . . . . . . . . . . . . . . . 7
3.2.2. Definition of Fields in Discard Summary Statistics
Block . . . . . . . . . . . . . . . . . . . . . . . . 7
4. Application Layer Metrics . . . . . . . . . . . . . . . . . . 8
4.1. Application Layer Loss/Duplication Statistics Summary
Block . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.1.1. Report Block Structure . . . . . . . . . . . . . . . . 9
4.1.2. Definition of Fields in Loss/Duplication Summary
Statistics Block . . . . . . . . . . . . . . . . . . . 9
5. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 11
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
6.1. New RTCP XR Block Type values . . . . . . . . . . . . . . 11
6.2. New RTCP XR SDP Parameters . . . . . . . . . . . . . . . . 12
6.3. Contact information for registrations . . . . . . . . . . 12
7. Security Considerations . . . . . . . . . . . . . . . . . . . 12
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
9.1. Normative References . . . . . . . . . . . . . . . . . . . 13
9.2. Informative References . . . . . . . . . . . . . . . . . . 13
Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 14
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Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14
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1. Introduction
RFC 3611 [RFC3611] defines seven report block formats for network
management and quality monitoring. However, some of these metrics
are mostly for multicast inference of network characteristics (MINC)
or voice over IP (VoIP) monitoring and not widely applicable to other
applications, e.g., video quality monitoring. This document focuses
on specifying new additional report block types used to convey loss,
duplication and discard summary statistics that are generically
designed for use in audio and video services.
The metrics belong to both the class of application layer metrics and
transport layer metrics defined in [MONARCH] (work in progress).
1.1. Applicability
The Report Blocks defined in this document can be applied to any
real-time applications that convey loss, duplication and discard
summary statistics.
2. Terminology
2.1. Standards Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
In addition, the following terms are defined:
Picture Type
Picture types used in the different video algorithms compose of
the key-frame and the Derivation frame. Key-frame is also called
a reference frame and used as a reference for predicting other
pictures. It is coded without prediction from other pictures.
The Derivation frame is derived from Key-frame using prediction
from the reference frame.
3. Transport Layer Metrics
3.1. Burst/Gap Loss Summsary Statistics Block
The metrics described here are intended to be used as described in
this section, in conjunction with information from the Measurement
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Information block (which MUST be present in the same RTCP packet as
the Burst/Gap Loss block) and also with the metric "cumulative number
of packets lost" provided in standard RTCP [RFC3550].
3.1.1. Report Block Structure
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BT=TBD |I| rsv. | block length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Burst Loss Rate | Gap Loss Rate |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Burst duration Mean | Burst duration Varianc |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.1.2. Definition of Fields in Loss Summary Statistics Block
block type (BT): 8 bits
Burst/Gap Loss Summsary Statistics Block is identified by the
constant <BGLSS>.
Interval Metric flag (I): 1 bit
This field is used to indicate whether the metrics block is an
Interval or a Cumulative report,
reserved: 7 bits
This field is reserved for future definition. In the absence of
such a definition, the bits in this field MUST be set to zero and
MUST be ignored by the receiver.
block length: 16 bits
The constant 2, in accordance with the definition of this field in
Section 3 of RFC 3611 [RFC3611].
SSRC of source: 32 bits
As defined in Section 4.1 of RFC3611 [RFC3611].
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Burst Loss Rate: 16 bits
The fraction of packets lost during bursts since the beginning of
reception, expressed as a fixed point number with the binary point
at the left edge of the field. This value is calculated by
dividing Packets Discarded in Bursts by Total Packets expected in
Bursts as follows:
Packets Loss in Bursts / Total Packets expected in Bursts
Gap Loss Rate: 16 bits
The fraction of packets lost during gaps since the beginning of
reception expressed as a fixed point number with the binary point
at the left edge of the field. This value is calculated by
dividing the difference between number of packets lost and Packets
lost in Bursts by the difference between Packets Expected and
Total Packets expected in Bursts as follows:
(number of packets lost - Packets Lost in Bursts) / (Packets
Expected - Total Packets expected in Bursts)
where "number of packets lost" is obtained from standard RTCP
[RFC3550] and Packets Expected is calculated as the difference
between "extended last sequence number" and "extended first
sequence number" (Interval or Cumulative) provided in the
Measurement Identity and Information block [MEASIDENT].
Note that if the metric is to be calculated on an Interval basis,
a difference must be taken between the current and preceding
values of "cumulative number of packets lost" in RTCP, to obtain
the "number of packets lost" for the reporting interval.
Burst duration Mean:16bits
The mean burst duration is obtained as the quotient:
mean = Sum of Burst Durations / Number of Bursts
where " Sum of Burst Durations " and "Number of Bursts"is obtained
from the RTCP XR Burst/Gap Discard Block.
Burst Duration Variance:16bits
The variance of the burst duration is obtained using the standard
result:
var = ( Sum of Squares of Burst Durations - Number of Bursts *
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mean^2 ) / (Number of Bursts - 1)
where " Sum of Squares of Burst Durations " and "Number of
Bursts"is obtained from the RTCP XR Burst/Gap Discard Block.
3.2. Burst/Gap Discard Summary Statistics Block
The metrics described here are intended to be used as described in
this section, in conjunction with information from the Measurement
Identity block (which MUST be present in the same RTCP packet as the
Burst/Gap Discard block) and also with the metric "number of packets
discarded" provided in the RTCP XR Discard Block [DISCARD]. The RTCP
XR Discard Block SHOULD be sent if the Burst/Gap Discard block is
sent, but the converse does not apply.
3.2.1. Report Block Structure
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BT=TBD |I| Rsv. | block length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Burst Discard Rate | Gap Discard Rate |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.2.2. Definition of Fields in Discard Summary Statistics Block
block type (BT): 8 bits
Burst/Gap Discard Summary Statistics Block is identified by the
constant <BGDSS>.
reserved: 8 bits
This field is reserved for future definition. In the absence of
such a definition, the bits in this field MUST be set to zero and
MUST be ignored by the receiver.
Interval Metric flag (I): 1 bit
This field is used to indicate whether the metrics block is an
Interval or a Cumulative report,
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reserved: 7 bits
This field is reserved for future definition. In the absence of
such a definition, the bits in this field MUST be set to zero and
MUST be ignored by the receiver.
block length: 16 bits
The constant 3, in accordance with the definition of this field in
Section 3 of RFC 3611 [RFC3611].
SSRC of source: 32 bits
As defined in Section 4.1 of RFC3611 [RFC3611].
Burst Discard Rate: 16 bits
The fraction of packets discarded during bursts since the
beginning of reception, expressed as a fixed point number with the
binary point at the left edge of the field. This value is
calculated by dividing Packets Discarded in Bursts by Total
Packets expected in Bursts as follows:
Packets Discarded in Bursts / Total Packets expected in Bursts
Gap Discard Rate: 16 bits
The fraction of packets discarded during gaps since the beginning
of reception expressed as a fixed point number with the binary
point at the left edge of the field. This value is calculated by
dividing the difference between number of packets discarded and
Packets Discarded in Bursts by the difference between Packets
Expected and Total Packets expected in Bursts as follows:
(number of packets discarded - Packets Discarded in Bursts) /
(Packets Expected - Total Packets expected in Bursts)
where "number of packets discarded" is obtained from the RTCP XR
Discard Block [DISCARD] and Packets Expected is calculated as the
difference between "extended last sequence number" and "extended
first sequence number" (Interval or Cumulative) provided in the
Measurement Information block [MEASIDENT].
4. Application Layer Metrics
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4.1. Application Layer Loss/Duplication Statistics Summary Block
This block reports statistics beyond the information carried in the
Statistics Summary Report Block RTCP packet specified in the section
4.6 of RFC 3611 [RFC3611]. Information is recorded about lost frames
,duplicated frames, lost partial frames. Such information can be
useful for network management and video quality monitoring.
4.1.1. Report Block Structure
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BT=TBD | |T|P| rsv. | block length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| begin_seq | end_seq |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of frames expected |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| lost_full_frames |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| dup_frames |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| lost_partial_frames |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4.1.2. Definition of Fields in Loss/Duplication Summary Statistics
Block
Block type (BT): 8 bits
Application Layer Loss/Duplication Statistics Summary Bloc is
identified by the constant <ALDSS>.
Picture type indicator (T): 1 bit
Picture types used in the different video algorithms compose of
key-frame and derivation frame. This field is used to indicate
the frame type to be reported. Bits set to 0 if the lost_frames
field or dup_frames field contain a key_frame report or reference
frame report, 1 if the lost_frames field and dup_frames field
contain other derivation frame report.
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P: 1 bit
Bit set to 1 if the partial_lost_frames field or the partial_dup_
frames field contains a report, 0 otherwise.
Rsv.: 6 bits
This field is reserved for future definition. In the absence of
such a definition, the bits in this field MUST be set to zero and
MUST be ignored by the receiver.
Block length: 16 bits
The constant 6, in accordance with the definition of this field in
Section 3 of RFC 3611 [RFC3611].
SSRC of source: 32 bits
As defined in Section 4.1 of RFC3611 [RFC3611].
begin_seq: 16 bits
As defined in Section 4.1 of RFC 3611 [RFC3611].
end_seq: 16 bits
As defined in Section 4.1 of RFC 3611 [RFC3611].
number of frames expected:32bits
A count of the number of frames expected, estimated if necessary.
If no frames have been received then this count shall be set to
Zero.
lost_full_frames: 32 bits
If one frame is completely lost, this frame is regarded as one
lost full_frame. The lost_full_frames is equivalent to the number
of lost_full_frames in the above sequence number interval.
dup_frames: 32 bits
Number of dup_frames in the above sequence number interval.
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lost_partial_frames: 32 bits
If one frame is partially lost, this frame is regarded as one lost
fractional frame. The lost_partial_frames is equivalent to the
number of lost_partial_frames in the above sequence number
interval.
5. 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 three 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
xr-format =
/ burst-gap-loss-stat
/ burst-gap-discard-stat
/ application-loss-dup-stat
Refer to Section 5.1 of RFC 3611 [RFC3611] for a detailed description
and the full syntax of the "rtcp-xr" attribute.
6. 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] .
6.1. New RTCP XR Block Type values
This document assigns three new block type value in the RTCP XR Block
Type Registry:
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Name: BGLSS
Long Name: Burst/Gap Loss Summsary Statistics Block
Value <BGLSS>
Reference: Section 5.1
Name: BGDSS
Long Name: Burst/Gap Discard Summary Statistics Block
Value <BGDSS>
Reference: Section 5.2
Name: ALDSS
Long Name: Application Layer Loss/Duplication Statistics Summary
Value <ALDSS>
Reference: Section 6.1
6.2. New RTCP XR SDP Parameters
This document also registers three new SDP [RFC4566] parameters for
the "rtcp-xr" attribute in the RTCP XR SDP Parameters Registry:
* " burst-gap-loss-stat "
* " burst-gap-discard-stat "
* "application-loss-dup-stat "
6.3. Contact information for registrations
The contact information for the registrations is:
Glen Zorn
Network Zen
227/358 Thanon Sanphawut
Bang Na, Bangkok 10110
Thailand
7. Security Considerations
The new RTCP XR report blocks proposed in this document introduces no
new security considerations beyond those described in [RFC3611].
8. Acknowledgements
The authors would like to thank Bill Ver Steeg, David R Oran, Ali
Begen,Colin Perkins, Roni Even,Youqing Yang, Wenxiao Yu and Yinliang
Hu for their valuable comments and suggestions on this document.
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9. References
9.1. Normative References
[DISCARD] Hunt, G., "RTCP XR Report Block for Discard metric
Reporting", ID draft-ietf-rtcp-xr-discard-02, May 2009.
[I-D.ietf-avt-rtp-svc]
Wenger, S., Wang, Y., Schierl, T., and A. Eleftheriadis,
"RTP Payload Format for Scalable Video Coding",
draft-ietf-avt-rtp-svc-27 (work in progress),
February 2011.
[MEASIDENT]
Wu, Q., "Measurement Identity and information Reporting
using SDES item and XR Block",
ID draft-ietf-xrblock-rtcp-xr-meas-identity-01,
October 2011.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2250] Hoffman, D., Fernando, G., Goyal, V., and M. Civanlar,
"RTP Payload Format for MPEG1/MPEG2 Video", RFC 2250,
January 1998.
[RFC3357] Koodli, R. and R. Ravikanth, "One-way Loss Pattern Sample
Metrics", RFC 3357, August 2002.
[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.
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
Protocol Extended Reports (RTCP XR)", RFC 3611,
November 2003.
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
Description Protocol", RFC 4566, July 2006.
[RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234, January 2008.
9.2. Informative References
[DSLF] Rahrer, T., Ed., Fiandra, Ed., and Wright, Ed., "Triple-
play Services Quality of Experience (QoE) Requirements",
DSL Forum Technical Report TR-126, December 2006.
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[MONARCH] Wu, Q., "Monitoring Architectures for RTP",
ID draft-ietf-avtcore-monarch-00, April 2011.
[PMOL] Clark, A., "Framework for Performance Metric Development",
ID draft-ietf-pmol-metrics-framework-08, January 2011.
Appendix A. Change Log
This document is separated from
draft-wu-xrblock-rtcp-xr-quality-monitoring-01 with a few editorial
changes and focuses on loss,duplication, discard, and summary
statistics metrics.
Authors' Addresses
Glen Zorn
Network Zen
77/440 Soi Phoomjit, Rama IV Road
Phra Khanong, Khlong Toie
Bangkok 10110
Thailand
Phone: +66 (0) 87 502 4274
Email: gwz@net-zen.net
Roland Schott
Deutsche Telekom
Deutsche-Telekom-Allee 7
Darmstadt 64295
Germany
Email: Roland.Schott@telekom.de
Qin Wu
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: sunseawq@huawei.com
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Rachel Huang
Huawei
101 Software Avenue, Yuhua District
Nanjing 210012
China
Email: Rachel@huawei.com
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