Internet Engineering Task Force (IETF) G. Zorn
Request for Comments: 7004 Network Zen
Category: Standards Track R. Schott
ISSN: 2070-1721 Deutsche Telekom
Q. Wu, Ed.
R. Huang
Huawei
September 2013
RTP Control Protocol (RTCP) Extended Report (XR) Blocks
for Summary Statistics Metrics Reporting
Abstract
This document defines three RTP Control Protocol (RTCP) Extended
Report (XR) blocks that allow the reporting of loss, duplication, and
discard summary statistics metrics in a range of RTP applications.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7004.
Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Zorn, et al. Standards Track [Page 1]
RFC 7004 Summary Stats XR Blocks September 2013
Table of Contents
1. Introduction ....................................................2
1.1. Summary Statistics Metrics .................................2
1.2. RTCP and RTCP Extended Reports .............................3
1.3. Performance Metrics Framework ..............................3
1.4. Applicability ..............................................3
2. Terminology .....................................................3
3. Transport-Related End-System Metrics ............................4
3.1. Burst/Gap Loss Summary 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 ..............................8
3.2.2. Definition of Fields in Burst/Gap Discard
Summary Statistics Block ............................8
4. Application-Level Metrics ......................................10
4.1. Frame Impairment Statistics Summary Block .................10
4.1.1. Report Block Structure .............................11
4.1.2. Definition of Fields in Frame Impairment
Statistics Summary Block ...........................11
5. SDP Signaling ..................................................13
5.1. SDP rtcp-xr Attribute Extension ...........................13
5.2. Offer/Answer Usage ........................................13
6. IANA Considerations ............................................13
6.1. New RTCP XR Block Type Values .............................13
6.2. New RTCP XR SDP Parameters ................................14
6.3. Contact Information for Registrations .....................14
7. Security Considerations ........................................14
8. Acknowledgements ...............................................14
9. References .....................................................14
9.1. Normative References ......................................14
9.2. Informative References ....................................15
Appendix A. Metrics Represented Using the Template from RFC 6390 .16
Zorn, et al. Standards Track [Page 2]
RFC 7004 Summary Stats XR Blocks September 2013
1. Introduction
1.1. Summary Statistics Metrics
This document defines three new block types to augment those defined
in [RFC3611] for use in a range of RTP applications:
o Burst/Gap Loss Summary Statistics Block
o Burst/Gap Discard Summary Statistics Block
o Frame Impairment Statistics Summary Block
The first two block types support the reporting of burst/gap loss and
burst/gap discard summary statistics including packet loss/discard
proportion, mean, and variance and belong to the class of transport-
related end-system metrics defined in [RFC6792]. These two blocks
are intended to be used in conjunction with information from the
Burst/Gap Loss Metrics Block [RFC6958] or Burst/Gap Discard Metrics
Block [RFC7003], on which these two blocks therefore depend. The
metrics in the Burst/Gap Loss Metrics Block and Burst/Gap Discard
Metrics Block are consistent with the definitions of "burst", "gap",
"loss", and "discard" in RTCP XR [RFC3611].
The third block supports the reporting of detailed video statistics
for each frame type, including the number of frames received, lost,
and discarded of each frame type in the Group of Pictures (GOP) and
additional data allowing the calculation of statistical parameters
(e.g., the proportion of each frame type impaired by packet loss and
discard). The metrics defined in this block belong to the class of
application-level metrics defined in [RFC6792].
1.2. RTCP and RTCP Extended 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 document defines a new Extended Report block for
use with [RFC3550] and [RFC3611].
1.3. Performance Metrics Framework
The RTP Monitoring Framework [RFC6792] provides guidelines for
reporting block format using RTCP XR. Metrics described in this
document are in accordance with the guidelines in [RFC6792].
Zorn, et al. Standards Track [Page 3]
RFC 7004 Summary Stats XR Blocks September 2013
1.4. Applicability
These metrics are applicable to a wide range of RTP applications and
reflect transient IP problems that affect user experience. They can
be used to form an accurate assessment of users' quality of
experience and influence sender strategies to mitigate the problem.
2. Terminology
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 term is defined:
Frame Type
In many cases, a video frame is compressed using different
algorithms. Frame type is used to identify different algorithms
for video frames. Two frame types used in the different video
algorithms are the Key frame and Derived frames. The Key frame is
independently coded without prediction from other pictures and
used as a reference frame for predicting other pictures. Derived
frames are predicatively coded and derived from a Key frame using
a prediction algorithm. If there is no video image compression,
all frames are Key frames.
3. Transport-Related End-System Metrics
3.1. Burst/Gap Loss Summary Statistics Block
This block extends packet loss and discard metrics defined in
Section 4.7.1 of [RFC3611]. The metrics described here are intended
to be used as described in this section, in conjunction with
information from the Measurement Information Block [RFC6776] (which
MUST be present in the same RTCP packet as the Burst/Gap Loss Metrics
Block [RFC6958]) and also with the metric "cumulative number of
packets lost" provided in standard RTCP [RFC3550]. Instances of this
metrics block use the synchronization source (SSRC) to refer to the
separate auxiliary Measurement Information Block [RFC6776], which
describes measurement periods in use (see [RFC6776], Section 4.2).
This metrics block relies on the measurement period 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 period is not received in the
same compound RTCP packet as this metrics block, this metrics block
MUST be discarded.
Zorn, et al. Standards Track [Page 4]
RFC 7004 Summary Stats XR Blocks September 2013
The metrics carried in this metrics block provide information
relevant to statistical parameters, including Burst Loss Rate, Gap
Loss Rate, Burst Duration Mean, and Burst Duration Variance, and are
measured at the receiving end of the RTP stream using burst/gap loss
metrics defined in [RFC6958] and other information that is sent
together with this report block.
3.1.1. Report Block Structure
The structure of the Burst/Gap Loss Summary Statistics Block is as
follows.
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=17 | I | Reserved | Block Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Burst Loss Rate | Gap Loss Rate |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Burst Duration Mean | Burst Duration Variance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.1.2. Definition of Fields in Loss Summary Statistics Block
Block Type (BT): 8 bits
A Burst/Gap Loss Summary Statistics Block is identified by the
constant 17.
Interval Metric flag (I): 2 bits
This field is used to indicate whether the burst/gap loss summary
statistics metrics are Sampled, Interval, or Cumulative metrics:
I=10: Interval Duration - the reported value applies to the
most recent measurement interval duration between successive
metrics reports.
I=11: Cumulative Duration - the reported value applies to the
accumulation period characteristic of cumulative measurements.
I=01: Sampled Value - the reported value is a sampled
instantaneous value.
In this document, the value I=00 is the reserved value and MUST
NOT be used.
Zorn, et al. Standards Track [Page 5]
RFC 7004 Summary Stats XR Blocks September 2013
Reserved: 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
ignored by the receiver (see [RFC6709], Section 4.2).
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 RFC 3611 [RFC3611].
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
immediately after the left-most bit. This value is calculated by
dividing Packets Lost in Bursts by Total Packets Expected in
Bursts, multiplying the result of the division by 32768 (0x8000),
and keeping only the integer part. The maximum value is thus
0x8000. Representing this as a formula:
integer-part( (Packets Lost in Bursts / Total Packets Expected in
Bursts) * 0x8000 )
If the measurement is unavailable, the value 0xFFFF MUST be
reported.
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
immediately after the left-most bit. 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, multiplying the result of the
division by 32768 (0x8000), and keeping only the integer part.
The maximum value is thus 0x8000. Representing this as a formula:
integer-part ( (number of packets lost - Packets Lost in Bursts)/
(Packets Expected - Total Packets Expected in Bursts) * 0x8000 )
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
Zorn, et al. Standards Track [Page 6]
RFC 7004 Summary Stats XR Blocks September 2013
sequence number" (Interval or Cumulative) provided in the
Measurement Identity and Information Block [RFC6776].
If the measurement is unavailable, the value 0xFFFF MUST be
reported.
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: 16 bits
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 Loss Metrics Block [RFC6958].
If the measurement is unavailable, the value 0xFFFF MUST be
reported.
Burst Duration Variance: 16 bits
The variance of the burst duration is obtained using the standard
result:
var = ( Sum of Squares of Burst Durations - Number of Bursts *
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 Loss Metrics Block
[RFC6958].
If the measurement is unavailable, the value 0xFFFF MUST be
reported.
3.2. Burst/Gap Discard Summary Statistics Block
This block extends packet loss and discard metrics defined in
Section 4.7.1 of [RFC3611]. The metrics described here are intended
to be used as described in this section, in conjunction with
information from the Measurement Identity Block [RFC6776] (which MUST
be present in the same RTCP packet as the Burst/Gap Discard Summary
Statistics Block).
Zorn, et al. Standards Track [Page 7]
RFC 7004 Summary Stats XR Blocks September 2013
These metrics provide information relevant to statistical parameters,
including Burst Discard Rate and Gap Discard Rate, and are measured
at the receiving end of the RTP stream using burst/gap discard
metrics defined in [RFC7003] and other information that is sent
together with this report block.
Instances of this metrics block use the synchronization source (SSRC)
to refer to the separate auxiliary Measurement Information block
[RFC6776] that describes measurement periods in use (see [RFC6776],
Section 4.2). This metrics block relies on the measurement period 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 period is not
received in the same compound RTCP packet as this metrics block, this
metrics block MUST be discarded.
3.2.1. Report Block Structure
The structure of the Burst/Gap Discard Summary Statistics Block is as
follows.
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=18 | I | Reserved | Block Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Burst Discard Rate | Gap Discard Rate |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.2.2. Definition of Fields in Burst/Gap Discard Summary Statistics
Block
Block Type (BT): 8 bits
A Burst/Gap Discard Summary Statistics Block is identified by the
constant 18.
Interval Metric flag (I): 2 bits
This field is used to indicate whether the burst/gap discard
summary statistics metrics are Sampled, Interval, or Cumulative
metrics:
I=10: Interval Duration - the reported value applies to the
most recent measurement interval duration between successive
metrics reports.
Zorn, et al. Standards Track [Page 8]
RFC 7004 Summary Stats XR Blocks September 2013
I=11: Cumulative Duration - the reported value applies to the
accumulation period characteristic of cumulative measurements.
I=01: Sampled Value - the reported value is a sampled
instantaneous value.
In this document, the value I=00 is the reserved value and MUST
NOT be used.
Reserved: 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
ignored by the receiver (see [RFC6709], Section 4.2).
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].
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 immediately after the left-most bit. This value is
calculated by dividing Packets Discarded in Bursts by Total
Packets Expected in Bursts, multiplying the result of the division
by 32768 (0x8000), and keeping only the integer part, according to
the formula:
integer-part( (Packets Discarded in Bursts / Total Packets
Expected in Bursts) * 0x8000 )
If the measurement is unavailable, the value 0xFFFF MUST be
reported.
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 immediately after the left-most bit. 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,
Zorn, et al. Standards Track [Page 9]
RFC 7004 Summary Stats XR Blocks September 2013
multiplying the result of the division by 32768 (0x8000), and
keeping only the integer part. The maximum value is thus 0x8000.
Representing this as a formula:
integer-part( (number of packets discarded - Packets Discarded in
Bursts) /(Packets Expected - Total Packets Expected in Bursts) *
0x8000 )
where "number of packets discarded" is obtained from the RTCP XR
Discard Count Block [RFC7002] and filled with the sum of packets
discarded due to early arrival (DT=1) and packets discarded due to
late arrival (DT=2) 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 [RFC6776]. In order for the Burst/
Gap Discard Summary Statistics Block to be meaningful, 2 instances
of the Discard Count Block with DT=1 and DT=2 MUST be included in
the same RTCP XR packet as the Burst/Gap Discard Summary
Statistics Block.
If the measurement is unavailable, the value 0xFFFF MUST be
reported.
4. Application-Level Metrics
4.1. Frame Impairment Statistics Summary Block
This block extends the statistics summary report mechanism defined in
Section 4.6 of [RFC3611] and reports statistics on which frame types
were affected beyond the information carried in the Statistics
Summary Report Block RTCP packet specified in Section 4.6 of
[RFC3611]. Information is measured at the receiving end of the RTP
stream and recorded about the number of frames received, lost frames,
duplicated frames, and lost partial frames. Such information can be
useful for network management and video quality monitoring.
Zorn, et al. Standards Track [Page 10]
RFC 7004 Summary Stats XR Blocks September 2013
4.1.1. Report Block Structure
The structure of the Frame Impairment Statistics Summary Block is as
follows.
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=19 |T| Reserved | Block Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| begin_seq | end_seq |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| discarded_frames |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| dup_frames |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| full_lost_frames |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| partial_lost_frames |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4.1.2. Definition of Fields in Frame Impairment Statistics Summary
Block
Block Type (BT): 8 bits
A Frame Impairment Statistics Summary Block is identified by the
constant 19.
Frame type indicator (T): 1 bit
This field is used to indicate the frame type to be reported. The
bit is set to 0 if the full_lost_frames, partial_lost_frames,
dup_frames, and discarded_frames fields contain Key frame
(reference frame) counts or 1 if they contain Derived frame
counts. Note that if both the Key frame and Derivation frame
report are sent, they should be sent in the same RTCP compound
packet using two Frame Impairment Statistics Summary Blocks.
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
ignored by the receiver (see [RFC6709], Section 4.2).
Zorn, et al. Standards Track [Page 11]
RFC 7004 Summary Stats XR Blocks September 2013
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 RFC 3611 [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 discarded frames (discarded_frames): 32 bits
Number of frames discarded in the above sequence number interval.
Number of duplicate frames (dup_frames): 32 bits
Number of duplicate frames received in the above sequence number
interval.
Number of full lost frames (full_lost_frames): 32 bits
A frame is either split across multiple packets or carried in only
one packet. If the whole frame or all the packets of the frame
are lost, this frame is regarded as one full_lost_frame. The
full_lost_frames can be inferred from packet(s) that comprise the
frame. The full_lost_frames is equivalent to the number of full
lost frames in the above sequence number interval.
Number of partial lost frames (partial_lost_frames): 32 bits
When a frame is split across multiple packets and some packets of
the frame are lost, this frame is regarded as one
partial_lost_frame. The partial_lost_frames can be inferred from
packets that comprise the frame. The value of the
partial_lost_frames field is equivalent to the number of partial
lost frames in the above sequence number interval.
Zorn, et al. Standards Track [Page 12]
RFC 7004 Summary Stats XR Blocks September 2013
5. SDP Signaling
RFC 3611 defines the use of SDP (Session Description Protocol)
[RFC4566] for signaling the use of XR blocks. However, XR blocks MAY
be used without prior signaling (see Section 5 of [RFC3611]).
5.1. SDP rtcp-xr Attribute Extension
This section augments the SDP [RFC4566] attribute "rtcp-xr" defined
in Section 5.1 of [RFC3611] by providing three additional values of
"xr-format" to signal the use of the report block defined in this
document. The ABNF [RFC5234] syntax is as follows.
xr-format =/ xr-bglss-block
/ xr-bgdss-block
/ xr-fiss-block
xr-bglss-block = "burst-gap-loss-stat"
xr-bgdss-block = "burst-gap-discard-stat"
xr-fiss-block = "frame-impairment-stat"
5.2. Offer/Answer Usage
When SDP is used in offer/answer context, the SDP Offer/Answer usage
defined in [RFC3611] for unilateral "rtcp-xr" attribute parameters
applies. For detailed usage of Offer/Answer for unilateral
parameter, refer to section 5.2 of [RFC3611].
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 RFC
3611.
6.1. New RTCP XR Block Type Values
This document assigns three new block type values in the "RTP Control
Protocol Extended Reports (RTCP XR) Block Type Registry":
Name: BGLSS
Long Name: Burst/Gap Loss Summary Statistics Block
Value 17
Reference: Section 3.1
Name: BGDSS
Long Name: Burst/Gap Discard Summary Statistics Block
Value 18
Reference: Section 3.2
Zorn, et al. Standards Track [Page 13]
RFC 7004 Summary Stats XR Blocks September 2013
Name: FISS
Long Name: Frame Impairment Statistics Summary Block
Value 19
Reference: Section 4.1
6.2. New RTCP XR SDP Parameters
This document also registers three new SDP [RFC4566] parameters for
the "rtcp-xr" attribute in the "RTP Control Protocol Extended Reports
(RTCP XR) Session Description Protocol (SDP) Parameters Registry":
* "burst-gap-loss-stat"
* "burst-gap-discard-stat"
* "frame-impairment-stat"
6.3. Contact Information for Registrations
The contact information for the registrations is:
Qin Wu (sunseawq@huawei.com)
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
7. Security Considerations
The new RTCP XR blocks in this document do not introduce any 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, Yinliang
Hu, Jing Zhao, Ray van Brandenburg, Claire Bi, Dan Romascanu, Alfred
Morton, Jr., Klaas Wierenga, Barry Leiba, Robert Sparks, Ralph Droms,
and Benoit Claise for their valuable comments and suggestions on this
document.
9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.
Jacobson, "RTP: A Transport Protocol for Real-Time
Applications", STD 64, RFC 3550, July 2003.
Zorn, et al. Standards Track [Page 14]
RFC 7004 Summary Stats XR Blocks September 2013
[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.
[RFC6776] Clark, A. and Q. Wu, "Measurement Identity and Information
Reporting Using a Source Description (SDES) Item and an
RTCP Extended Report (XR) Block", RFC 6776, October 2012.
[RFC6958] Clark, A., Zhang, S., Zhao, J., and Q. Wu, "RTP Control
Protocol (RTCP) Extended Report (XR) Block for Burst/Gap
Loss Metric Reporting", RFC 6958, May 2013.
[RFC7002] Clark, A., Zorn, G., and Q. Wu, "RTP Control Protocol
(RTCP) Extended Report (XR) Block for Discard Count Metric
Reporting", RFC 7002, September 2013.
[RFC7003] Clark, A., Huang, R., and Q. Wu, Ed., "RTP Control
Protocol (RTCP) Extended Report (XR) Block for Burst/Gap
Discard Metric Reporting", RFC 7003, September 2013.
9.2. Informative References
[RFC6390] Clark, A. and B. Claise, "Guidelines for Considering New
Performance Metric Development", BCP 170, RFC 6390,
October 2011.
[RFC6709] Carpenter, B., Aboba, B., and S. Cheshire, "Design
Considerations for Protocol Extensions", RFC 6709,
September 2012.
[RFC6792] Wu, Q., Hunt, G., and P. Arden, "Guidelines for Use of the
RTP Monitoring Framework", RFC 6792, November 2012.
Zorn, et al. Standards Track [Page 15]
RFC 7004 Summary Stats XR Blocks September 2013
Appendix A. Metrics Represented Using the Template from RFC 6390
a. Burst Loss Rate Metric
* Metric Name: RTP Burst Loss Rate
* Metric Description: The fraction of packets lost during bursts
since the beginning of reception for RTP traffic.
* Method of Measurement or Calculation: See Section 3.1.2, Burst
Loss Rate definition.
* Units of Measurement: See Section 3.1.2, Burst Loss Rate
definition.
* Measurement Point(s) with Potential Measurement Domain: See
Section 3.1, 2nd paragraph.
* Measurement Timing: See Section 3.1, 1st paragraph for
measurement timing and Section 3.1.2 for Interval Metric flag.
* Use and Applications: See Section 1.4.
* Reporting Model: See RFC 3611.
b. Gap Loss Rate Metric
* Metric Name: RTP Gap Loss Rate
* Metric Description: The fraction of packets lost during gaps
since the beginning of reception for RTP traffic.
* Method of Measurement or Calculation: See Section 3.1.2, Gap
Loss Rate definition.
* Units of Measurement: See Section 3.1.2, Gap Loss Rate
definition.
* Measurement Point(s) with Potential Measurement Domain: See
Section 3.1, 2nd paragraph.
* Measurement Timing: See Section 3.1, 1st paragraph for
measurement timing and Section 3.1.2 for Interval Metric flag.
* Use and Applications: See Section 1.4.
* Reporting Model: See RFC 3611.
Zorn, et al. Standards Track [Page 16]
RFC 7004 Summary Stats XR Blocks September 2013
c. Burst Duration Mean Metric
* Metric Name: RTP Burst Duration Mean
* Metric Description: The mean duration of the burst periods
that have occurred since the beginning of reception for RTP
traffic.
* Method of Measurement or Calculation: See Section 3.1.2, Burst
Loss Rate definition.
* Units of Measurement: This metric is expressed in
milliseconds.
* Measurement Point(s) with Potential Measurement Domain: See
Section 3.1, 2nd paragraph.
* Measurement Timing: See Section 3.1, 1st paragraph for
measurement timing and Section 3.1.2 for Interval Metric flag.
* Use and Applications: See Section 1.4.
* Reporting Model: See RFC 3611.
d. Burst Duration Variance Metric
* Metric Name: RTP Burst Duration Variance
* Metric Description: The variance duration of the burst periods
that have occurred since the beginning of reception for RTP
traffic.
* Method of Measurement or Calculation: See Section 3.1.2, Burst
Duration Variance definition.
* Units of Measurement: See Section 3.1.2, Burst Duration
Variance definition.
* Measurement Point(s) with Potential Measurement Domain: See
Section 3.1, 2nd paragraph.
* Measurement Timing: See Section 3.1, 1st paragraph for
measurement timing and Section 3.1.2 for Interval Metric flag.
* Use and Applications: See Section 1.4.
* Reporting Model: See RFC 3611.
Zorn, et al. Standards Track [Page 17]
RFC 7004 Summary Stats XR Blocks September 2013
e. Burst Discard Rate Metric
* Metric Name: RTP Burst Discard Rate
* Metric Description: The fraction of packets discarded during
bursts since the beginning of reception for RTP traffic.
* Method of Measurement or Calculation: See Section 3.2.2, Burst
Discard Rate definition.
* Units of Measurement: See Section 3.2.2, Burst Discard Rate
definition.
* Measurement Point(s) with Potential Measurement Domain: See
Section 3.2, 2nd paragraph.
* Measurement Timing: See Section 3.2, 3rd paragraph for
measurement timing and Section 3.1.2 for Interval Metric flag.
* Use and Applications: See Section 1.4.
* Reporting Model: See RFC 3611.
f. Gap Discard Rate Metric
* Metric Name: RTP Gap Discard Rate
* Metric Description: The fraction of packets discarded during
gaps since the beginning of reception for RTP traffic.
* Method of Measurement or Calculation: See Section 3.2.2, Gap
Discard Rate definition.
* Units of Measurement: See Section 3.2.2, Gap Discard Rate
definition.
* Measurement Point(s) with Potential Measurement Domain: See
Section 3.2, 2nd paragraph.
* Measurement Timing: See Section 3.2, 3rd paragraph for
measurement timing and Section 3.1.2 for Interval Metric flag.
* Use and Applications: See Section 1.4.
* Reporting Model: See RFC 3611.
Zorn, et al. Standards Track [Page 18]
RFC 7004 Summary Stats XR Blocks September 2013
g. Number of Discarded Frames Metric
* Metric Name: Number of discarded frames in RTP
* Metric Description: Number of frames discarded in a certain
sequence number interval for RTP traffic.
* Method of Measurement or Calculation: See Section 4.1.2,
Number of discarded frames definition. This metric is
directly measured and can be inferred from packet(s) that
comprise the frame.
* Units of Measurement: This metric is expressed as a 32-bit
unsigned integer value.
* Measurement Point(s) with Potential Measurement Domain: See
Section 4.1, 1st paragraph.
* Measurement Timing: See Section 4.1, Number of discarded
frames definition. This metric relies on the sequence number
interval and RTCP RR packet of [RFC3550] to determine
measurement timing.
* Use and Applications: See Section 1.4.
* Reporting Model: See RFC 3611.
h. Number of Duplicate Frames Metric
* Metric Name: Number of duplicate frames in RTP
* Metric Description: Number of frames duplicated in a certain
sequence number interval for RTP traffic.
* Method of Measurement or Calculation: See Section 4.1.2,
Number of duplicate frames definition. This metric is
directly measured and can be inferred from packet(s) that
comprise the frame.
* Units of Measurement: This metric is expressed as a 32-bit
unsigned integer value.
* Measurement Point(s) with Potential Measurement Domain: See
Section 4.1, 1st paragraph.
* Measurement Timing: See Section 4.1, Number of duplicate
frames definition. This metric relies on the sequence number
interval to determine measurement timing.
Zorn, et al. Standards Track [Page 19]
RFC 7004 Summary Stats XR Blocks September 2013
* Use and Applications: See Section 1.4.
* Reporting Model: See RFC 3611.
i. Number of Full Lost Frames Metric
* Metric Name: Number of full lost frames in RTP
* Metric Description: A frame is either split across multiple
RTP packets or carried in only one RTP packet. If the whole
frame or all the packets of the frame is lost, this frame is
regarded as one full_lost_frame.
* Method of Measurement or Calculation: See Section 4.1.2,
Number of full lost frames definition.
* Units of Measurement: This metric is expressed as a 32-bit
unsigned integer value.
* Measurement Point(s) with Potential Measurement Domain: See
Section 4.1, 1st paragraph.
* Measurement Timing: See Section 4.1, Number of full lost
frames definition. This metric relies on the sequence number
interval to determine measurement timing.
* Use and Applications: See Section 1.4.
* Reporting Model: See RFC 3611.
j. Number of Partial Lost Frames Metric
* Metric Name: Number of partial lost frames in RTP
* Metric Description: When a frame is split across multiple RTP
packets and some RTP packets of the frame are lost, this frame
is regarded as one partial_lost_frame.
* Method of Measurement or Calculation: See Section 4.1.2,
Number of partial lost frames definition.
* Units of Measurement: This metric is expressed as a 32-bit
unsigned integer value.
* Measurement Point(s) with Potential Measurement Domain: See
Section 4.1, 1st paragraph.
Zorn, et al. Standards Track [Page 20]
RFC 7004 Summary Stats XR Blocks September 2013
* Measurement Timing: See Section 4.1, Number of partial lost
frames definition. This metric relies on the sequence number
interval to determine measurement timing.
* Use and Applications: See Section 1.4.
* Reporting Model: See RFC 3611.
Authors' Addresses
Glen Zorn
Network Zen
227/358 Thanon Sanphawut
Bang Na, Bangkok 10260
Thailand
Phone: +66 (0) 909-201060
EMail: glenzorn@gmail.com
Roland Schott
Deutsche Telekom
Deutsche-Telekom-Allee 7
Darmstadt 64295
Germany
EMail: Roland.Schott@telekom.de
Qin Wu (editor)
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
EMail: sunseawq@huawei.com
Rachel Huang
Huawei
101 Software Avenue, Yuhua District
Nanjing 210012
China
EMail: Rachel@huawei.com
Zorn, et al. Standards Track [Page 21]