XR Block Working Group V. Singh Internet-Draft Aalto University Intended status: Standards Track R. Huang Expires: April 20, 2014 R. Even Huawei October 17, 2013 Additional RTP Control Protocol (RTCP) Extended Report (XR) Metrics for WebRTC Statistics API draft-singh-xrblock-webrtc-additional-stats-01 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. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on April 20, 2014. Copyright Notice Copyright (c) 2013 IETF Trust and the persons identified as the document authors. All rights reserved. Singh, et al. Expires April 20, 2014 [Page 1] Internet-Draft Additional RTCP XR Metrics for WebRTC October 2013 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. 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 Retransmitted Packets Received . 4 2.1.3. Cumulative Number of Packets Repaired . . . . . . . . 4 2.1.4. Frame Impairment Metrics . . . . . . . . . . . . . . 4 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 4. Security Considerations . . . . . . . . . . . . . . . . . . . 4 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 6.1. Normative References . . . . . . . . . . . . . . . . . . 5 6.2. Informative References . . . . . . . . . . . . . . . . . 6 Appendix A. Metrics represented using RFC6390 Template . . . . . 6 Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 7 B.1. 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. RTCWEB-STATS [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 Singh, et al. Expires April 20, 2014 [Page 2] Internet-Draft Additional RTCP XR Metrics for WebRTC October 2013 basic metrics from RTCP SR/RR are not sufficient for precise quality monitoring or troubleshooting. This document proposes to expose the RTCP XR metrics to better complement the identifiers already in the statistics registry. In depth discussion about the XR metrics candidates is carried out in [I-D.huang-xrblock-rtcweb-rtcp-xr-metrics]. The Javascript application on the receiving endpoint extracts the statistics for the remote (incoming) media stream from the browser's RTP using the Stats API [W3C.WD-webrtc-20130910]. There are multiple ways to exchange these observed identifiers with the remote party, one of which is to use corresponding RTCP Extension Reports (XRs) [RFC3611] and query the statistic identifiers for the local (outgoing) media stream. However, the exchange of statistics of the local stream are currently outside the scope of WebRTC. 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 the group of identifiers are well defined on a ReportGroup corresponding to an SSRC. In practice the application MUST be able to query the statistic identifiers on an incoming media stream (remote stream). Depending on the support of the corresponding XR report the endpoint MAY be able to query the statistic identifier for the outgoing media stream (local 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, Appendix A of [RFC7002] Name: OctetsDiscarded Singh, et al. Expires April 20, 2014 [Page 3] Internet-Draft Additional RTCP XR Metrics for WebRTC October 2013 Definition: Cumulative Number of octets discarded, Appendix A of [I-D.ietf-xrblock-rtcp-xr-bytes-discarded-metric] 2.1.2. Cumulative Number of Retransmitted Packets Received Name: PacketsRetx Definition: See Appendix A of this document, [RFCXXXX]. RFC EDITOR NOTE: please change XXXX in [RFCXXXX] by the new RFC number, when assigned and remove this note. 2.1.3. Cumulative Number of Packets Repaired Name: PacketsRepaired Definition: Appendix A (b) of [I-D.huang-xrblock-post-repair-loss-count] 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] 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 Singh, et al. Expires April 20, 2014 [Page 4] Internet-Draft Additional RTCP XR Metrics for WebRTC October 2013 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. [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. [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. Singh, et al. Expires April 20, 2014 [Page 5] Internet-Draft Additional RTCP XR Metrics for WebRTC October 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, . Appendix A. Metrics represented using RFC6390 Template RFC EDITOR NOTE: please change XXXX in [RFCXXXX] by the new RFC number, when assigned and remove this note. a. Number of Packets Retransmitted Metric * Metric Name: Cumulative number of RTP Packets retransmitted * Metric Description: Total number of packets retransmitted from the beginning of the session. * Method of Measurement or Calculation: Cumulative number of retransmitted packets received from the beginning of the session. The measured value is an unsigned value. If the measured value exceeds 0xFFFFFFFD, the value 0xFFFFFFFE MUST be reported to indicate an over-range measurement. If the measurement is unavailable, the value 0xFFFFFFFF MUST be reported. * Units of Measurement: The counter is increased by one for every retransmitted RTP packet that is received. Singh, et al. Expires April 20, 2014 [Page 6] Internet-Draft Additional RTCP XR Metrics for WebRTC October 2013 * Measurement Point(s) with Potential Measurement Domain: This metric reports the number of retransmitted RTP packets received by the receiver. The measurement of these metrics are made at the receiving end of the retransmission stream and the association of the retransmission and original streams should refer to section 5.3 of [RFC4588]. * Measurement Timing: This metric is applicable to cumulative measurements, which may be the duration of the ongoing RTP session. * Use and applications: See section 1 of [RFCXXXX]. * Reporting model: Queried periodically by the WebRTC Statistics API. Appendix B. Change Log Note to the RFC-Editor: please remove this section prior to publication as an RFC. B.1. 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 Singh, et al. Expires April 20, 2014 [Page 7] Internet-Draft Additional RTCP XR Metrics for WebRTC October 2013 Roni Even Huawei 14 David Hamelech Tel Aviv 64953 Israel Email: roni.even@mail01.huawei.com Singh, et al. Expires April 20, 2014 [Page 8]