XR Block Working Group V. Singh
Internet-Draft Aalto University
Intended status: Standards Track R. Huang
Expires: August 18, 2014 R. Even
Huawei
February 14, 2014
Additional RTP Control Protocol (RTCP) Extended Report (XR) Metrics for
WebRTC Statistics API
draft-singh-xrblock-webrtc-additional-stats-02
Abstract
This document describes a list of additional identifiers used in
WebRTC's Javascript statistics API. These identifiers are a set of
RTCP XR metrics related to the transport of multimedia flows.
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Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Candidate XR Block Metrics for WebRTC Statistics API . . . 3
2.1. Variables from XR Blocks . . . . . . . . . . . . . . . . 3
2.1.1. Packets and Octets Discarded . . . . . . . . . . . . 3
2.1.2. Cumulative Number of Packets Repaired . . . . . . . . 4
2.1.3. Burst Packet Loss or Discarded . . . . . . . . . . . 4
2.1.4. Frame Impairment Metrics . . . . . . . . . . . . . . 4
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . 5
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Normative References . . . . . . . . . . . . . . . . . . 5
6.2. Informative References . . . . . . . . . . . . . . . . . 6
Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 7
A.1. changes in draft-singh-xrblock-webrtc-additional-stats-01 7
A.2. changes in draft-singh-xrblock-webrtc-additional-stats-00 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
Web-based real-time communication (WebRTC) deployments are emerging
and applications need to be able to estimate the service quality. If
sufficient information (metrics or statistics) are provided to the
applications, it can attempt to improve the media quality.
[I-D.ietf-rtcweb-use-cases-and-requirements] specifies a requirement
for statistics:
F38 The browser must be able to collect statistics, related to the
transport of audio and video between peers, needed to estimate
quality of experience.
The [I-D.alvestrand-rtcweb-stats-registry] describes a registration
procedure for metrics reported by the Javascript API. It currently
lists basic metrics reported in the RTCP Sender and Receiver Report
(SR/RR) to fulfill this requirement. However, the basic metrics from
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RTCP SR/RR are not sufficient for precise quality monitoring or
troubleshooting. This document proposes to expose the RTCP XR
metrics to complement the identifiers already in the statistics
registry [I-D.alvestrand-rtcweb-stats-registry]. In depth discussion
about the XR metrics candidates is carried out in
[I-D.huang-xrblock-rtcweb-rtcp-xr-metrics].
The WebRTC application has two options to extract the statistics: 1)
the browser monitors the local (outgoing) and remote (incoming) RTP
stream and exposes metrics to the application via the Stats API
[W3C.WD-webrtc-20130910], or 2) the browser measures the remote
(incoming) RTP stream and exposes the metrics to the other
participant by sending the appropriate RTCP XR. At the moment
[I-D.ietf-rtcweb-rtp-usage] does not specify the use of any RTCP XRs
and since their usage is optional, the exchange of statistics between
participants or a monitoring server is outside the scope of this
document.
2. Candidate XR Block Metrics for WebRTC Statistics API
This document describes a list of additional identifiers to
complement the identifiers in Section 4.1 of
[I-D.alvestrand-rtcweb-stats-registry] and these group of identifiers
are defined on a ReportGroup corresponding to an SSRC. In practice
the application MUST be able to query the statistic identifiers on
both an incoming (remote) and outgoing (local) media stream.
Depending on the support of the corresponding XR report the endpoint
MAY be able to query the reception statistics for its outgoing
(local) media stream.
The following contact information is used for all registrations in
this document:
Contact: Varun Singh
mailto:varun.singh@iki.fi
tel:+358-9-470-24785
2.1. Variables from XR Blocks
2.1.1. Packets and Octets Discarded
Name: PacketsDiscarded
Definition: Cumulative Number of RTP packets discarded due to late or
early-arrival, Appendix A (a) of [RFC7002].
Name: OctetsDiscarded
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Definition: Cumulative Number of octets discarded due to late or
early-arrival, Appendix A of
[I-D.ietf-xrblock-rtcp-xr-bytes-discarded-metric]
2.1.2. Cumulative Number of Packets Repaired
Name: PacketsRepaired
Definition: The cumulative number of lost RTP packets repaired after
applying a error-resilience mechanism, Appendix A (b) of
[I-D.huang-xrblock-post-repair-loss-count]. To clarify, the value is
upper bound to the cumulative number of lost packets.
2.1.3. Burst Packet Loss or Discarded
Name: BurstPacketDiscarded
Definition: The total number of RTP packets discarded during discard
bursts, Appendix A (b) of [RFC7003].
Name: BurstPacketLost
Definition: The total number of RTP packets lost during loss bursts,
Appendix A (c) of [RFC6958].
Name: BurstCount
Definition: The cumulative number of bursts of lost RTP packets,
Appendix A (e) of [RFC6958].
[RFC3611] recommends a Gmin value of 16.
2.1.4. Frame Impairment Metrics
Name: FullFramesLostCount
Definition: Number of full frames lost, Appendix A (i) of [RFC7004]
Name: PartialFramesLostCount
Definition: Number of frames partially lost, Appendix A (j) of
[RFC7004]
Name: FramesDiscardedCount
Definition: Number of full frames discarded, Appendix A (g) of
[RFC7004]
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3. IANA Considerations
This document requests IANA to update the registry described in
[I-D.alvestrand-rtcweb-stats-registry] with the identifiers defined
in Section 2.
4. Security Considerations
The security considerations of
[I-D.alvestrand-rtcweb-stats-registry], apply.
5. Acknowledgements
This document is a product of discussion in XRBLOCK WG, initial
motivation for this documented is discussed in
[I-D.huang-xrblock-rtcweb-rtcp-xr-metrics]
The authors would like to thank Al Morton, Colin Perkins, Dan
Romascanu, and Shida Schubert, for their valuable comments and
suggestions on earlier version of this document.
6. References
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[I-D.alvestrand-rtcweb-stats-registry]
Alvestrand, H., "A Registry for WebRTC statistics
identifiers", draft-alvestrand-rtcweb-stats-registry-00
(work in progress), September 2012.
[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.
[RFC4588] Rey, J., Leon, D., Miyazaki, A., Varsa, V., and R.
Hakenberg, "RTP Retransmission Payload Format", RFC 4588,
July 2006.
[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.
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[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, "RTP Control Protocol
(RTCP) Extended Report (XR) Block for Burst/Gap Discard
Metric Reporting", RFC 7003, September 2013.
[I-D.ietf-xrblock-rtcp-xr-bytes-discarded-metric]
Singh, V., Ott, J., and I. Curcio, "RTP Control Protocol
(RTCP) Extended Report (XR) for Bytes Discarded Metric",
draft-ietf-xrblock-rtcp-xr-bytes-discarded-metric-00 (work
in progress), October 2013.
[I-D.huang-xrblock-post-repair-loss-count]
Huang, R. and V. Singh, "RTP Control Protocol (RTCP)
Extended Report (XR) for Post-Repair Non-Run Length
Encoding (RLE) Loss Count Metrics", draft-huang-xrblock-
post-repair-loss-count-00 (work in progress), September
2013.
[RFC7004] Zorn, G., Schott, R., Wu, Q., and R. Huang, "RTP Control
Protocol (RTCP) Extended Report (XR) Blocks for Summary
Statistics Metrics Reporting", RFC 7004, September 2013.
6.2. Informative References
[I-D.ietf-rtcweb-use-cases-and-requirements]
Holmberg, C., Hakansson, S., and G. Eriksson, "Web Real-
Time Communication Use-cases and Requirements", draft-
ietf-rtcweb-use-cases-and-requirements-10 (work in
progress), December 2012.
[I-D.huang-xrblock-rtcweb-rtcp-xr-metrics]
Huang, R., Even, R., and V. Singh, "Consideration for
Selecting RTCP Extended Report (XR) Metrics for RTCWEB
Statistics API", draft-huang-xrblock-rtcweb-rtcp-xr-
metrics-01 (work in progress), July 2013.
[W3C.WD-webrtc-20130910]
Bergkvist, A., Burnett, D., Jennings, C., and A.
Narayanan, "WebRTC 1.0: Real-time Communication Between
Browsers", World Wide Web Consortium WD WD-
webrtc-20130910, September 2013,
<http://www.w3.org/TR/2013/WD-webrtc-20130910>.
[I-D.ietf-rtcweb-rtp-usage]
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Perkins, C., Westerlund, M., and J. Ott, "Web Real-Time
Communication (WebRTC): Media Transport and Use of RTP",
draft-ietf-rtcweb-rtp-usage-11 (work in progress),
December 2013.
Appendix A. Change Log
Note to the RFC-Editor: please remove this section prior to
publication as an RFC.
A.1. changes in draft-singh-xrblock-webrtc-additional-stats-01
o Addressed comments from the Vancouver IETF meeting.
o Added Burst discard/loss metric.
o Removed retransmission metric.
A.2. changes in draft-singh-xrblock-webrtc-additional-stats-00
o Clarified measurement points for remote (incoming) media stream
and local (outgoing) media stream.
o Added this section.
Authors' Addresses
Varun Singh
Aalto University
School of Electrical Engineering
Otakaari 5 A
Espoo, FIN 02150
Finland
Email: varun@comnet.tkk.fi
URI: http://www.netlab.tkk.fi/~varun/
Rachel Huang
Huawei
101 Software Avenue, Yuhua District
Nanjing, CN 210012
China
Email: rachel.huang@huawei.com
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Roni Even
Huawei
14 David Hamelech
Tel Aviv 64953
Israel
Email: roni.even@mail01.huawei.com
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