Audio/Video Transport Working Group A. Clark Internet-Draft Telchemy Intended status: Standards Track V. Singh Expires: July 14, 2013 Aalto University Q. Wu Huawei January 10, 2013 RTP Control Protocol (RTCP) Extended Report (XR) Block for Jitter Buffer Metric Reporting draft-ietf-xrblock-rtcp-xr-jb-06.txt Abstract This document defines an RTP Control Protocol (RTCP) Extended Report (XR) Block that allows the reporting of Jitter Buffer metrics for a range of RTP applications. 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 July 14, 2013. 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 Clark, et al. Expires July 14, 2013 [Page 1] Internet-Draft RTCP XR Jitter Buffer January 2013 the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. 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. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1. Standards Language . . . . . . . . . . . . . . . . . . . . 4 3. Jitter Buffer Metrics Block . . . . . . . . . . . . . . . . . 5 3.1. Report Block Structure . . . . . . . . . . . . . . . . . . 5 3.2. Definition of Fields in Jitter Buffer Metrics Block . . . 5 4. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 8 4.1. SDP rtcp-xr-attrib Attribute Extension . . . . . . . . . . 8 4.2. Offer/Answer Usage . . . . . . . . . . . . . . . . . . . . 8 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 5.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 9 5.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 9 5.3. Contact information for registrations . . . . . . . . . . 9 6. Security Considerations . . . . . . . . . . . . . . . . . . . 10 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 11 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 9.1. Normative References . . . . . . . . . . . . . . . . . . . 13 9.2. Informative References . . . . . . . . . . . . . . . . . . 13 Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 14 A.1. draft-ietf-xrblock-rtcp-xr-jb-05 . . . . . . . . . . . . . 14 A.2. draft-ietf-xrblock-rtcp-xr-jb-03 . . . . . . . . . . . . . 14 A.3. draft-ietf-xrblock-rtcp-xr-jb-02 . . . . . . . . . . . . . 14 A.4. draft-ietf-xrblock-rtcp-xr-jb-01 . . . . . . . . . . . . . 14 A.5. draft-ietf-xrblock-rtcp-xr-jb-00 . . . . . . . . . . . . . 14 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16 Clark, et al. Expires July 14, 2013 [Page 2] Internet-Draft RTCP XR Jitter Buffer January 2013 1. Introduction 1.1. Jitter Buffer Metrics Block This document 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 end system metrics defined in [RFC6792]. Instances of this Metrics Block refer by Synchronization source (SSRC) to the separate auxiliary Measurement Information block [RFC6776] 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] defines 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 Performance Metrics Framework [RFC6390] provides guidance on the definition and specification of performance metrics. The RTP Monitoring Architectures [RFC6792] provides guideline for reporting block format using RTCP XR. Metrics described in this draft are in accordance with the guidelines in [RFC6390]and [RFC6792]. 1.4. Applicability Real-time applications employ a jitter buffer to absorb jitter introduced on the path from source to destination. These metrics are used to report how the jitter buffer at the receiving end of RTP stream behaves as a result of jitter in the network and are applicable to a range of RTP applications. These metrics reflect how terminal-related factors affect real-time application quality and are useful to provide better end-user quality of experience (QoE). Clark, et al. Expires July 14, 2013 [Page 3] Internet-Draft RTCP XR Jitter Buffer January 2013 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]. Clark, et al. Expires July 14, 2013 [Page 4] Internet-Draft RTCP XR Jitter Buffer January 2013 3. 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 [RFC6776] which describes the measurement interval in use. This Metrics 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 Metrics Block, this Metrics Block should be discarded. 3.1. Report Block Structure JB Metrics Block 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=NJB | I |C| Rsvd. | block length=3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SSRC of Source | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | JB nominal | JB maximum | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | JB high water mark | JB low water mark | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: Report Block Structure 3.2. 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: Clark, et al. Expires July 14, 2013 [Page 5] Internet-Draft RTCP XR Jitter Buffer January 2013 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. Jitter Buffer Configuration (C): 1 bit This field is used to identify the jitter buffer method in use at the receiver, according to the following code: 0 = Fixed jitter buffer 1 = Adaptive jitter buffer Reserved (Rsvd.): 5 bits These bits are reserved. They MUST be set to zero by senders ignored by receivers (See [RFC6709] section 4.2). Block Length: 16 bits The length of this report block in 32-bit words, minus one, in accordance with the definition in [RFC3611]. This field MUST be set to 3 to match the fixed length of the report block. 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. It is calculated based on the difference between the receipt time and the playout time for the packet that arrives 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 MUST be reported to indicate an over-range measurement. If the Clark, et al. Expires July 14, 2013 [Page 6] Internet-Draft RTCP XR Jitter Buffer January 2013 measurement is unavailable, the value 0xFFFF MUST 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. It is calculated based on the difference between the receipt time and the playout time for the earliest arriving packet. In simple queue implementations this may correspond to the size of the jitter buffer. In adaptive jitter buffer implementations, this value may vary dynamically from JB low water mark to JB high water mark (See below). This parameter MUST be provided for both fixed and adaptive jitter buffer implementations. If the measured value exceeds 0xFFFD, the value 0xFFFE MUST be reported to indicate an over-range measurement. If the measurement is unavailable, the value 0xFFFF MUST be reported. jitter buffer high water mark (JB high water mark): 16 bits This is the highest value of the jitter buffer nominal delay in milliseconds which occurred at any time during the reporting interval. This parameter MUST be provided for adaptive jitter buffer implementations and its value MUST be set to JB maximum for fixed jitter buffer implementations. If the measured value exceeds 0xFFFD, the value 0xFFFE MUST be reported to indicate an over-range measurement. If the measurement is unavailable, the value 0xFFFF MUST be reported. jitter buffer low water mark (JB low water mark): 16 bits This is the lowest value of the jitter buffer nominal delay in milliseconds which occurred at any time during the reporting interval. This parameter MUST be provided for adaptive jitter buffer implementations and its value MUST be set to JB maximum for fixed jitter buffer implementations. If the measured value exceeds 0xFFFD, the value 0xFFFE MUST be reported to indicate an over-range measurement. If the measurement is unavailable, the value 0xFFFF MUST be reported. Clark, et al. Expires July 14, 2013 [Page 7] Internet-Draft RTCP XR Jitter Buffer January 2013 4. SDP Signaling [RFC3611] 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). 4.1. SDP rtcp-xr-attrib Attribute Extension 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. xr-format =/ xr-jb-block xr-jb-block = "jitter-bfr" 4.2. 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]. Clark, et al. Expires July 14, 2013 [Page 8] Internet-Draft RTCP XR Jitter Buffer January 2013 5. 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]. 5.1. 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.] 5.2. New RTCP XR SDP Parameter This document also registers a new parameter "jitter-bfr" in the "RTCP XR SDP Parameters Registry". 5.3. 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 Clark, et al. Expires July 14, 2013 [Page 9] Internet-Draft RTCP XR Jitter Buffer January 2013 6. 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. Clark, et al. Expires July 14, 2013 [Page 10] Internet-Draft RTCP XR Jitter Buffer January 2013 7. Contributors Geoff Hunt wrote the initial draft of this document. Clark, et al. Expires July 14, 2013 [Page 11] Internet-Draft RTCP XR Jitter Buffer January 2013 8. Acknowledgments The authors gratefully acknowledge reviews and feedback provided 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, Hideaki Yamada,Claire Bi,Colin Perkin, Dan Romascanu, Kevin Gross and Glen Zorn. Clark, et al. Expires July 14, 2013 [Page 12] Internet-Draft RTCP XR Jitter Buffer January 2013 9. References 9.1. 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. [RFC6709] Carpenter, B., Aboba, B., and S. Cheshire, "Design Considerations for Protocol Extensions", RFC 6709, September 2012. [RFC6776] Wu, Q., "Measurement Identity and information Reporting using SDES item and XR Block", RFC 6776, August 2012. 9.2. Informative References [RFC6390] Clark, A. and B. Claise, "Framework for Performance Metric Development", RFC 6390, October 2011. [RFC6792] Hunt, G., Wu, Q., and P. Arden, "Monitoring Architectures for RTP", RFC 6792, November 2012. Clark, et al. Expires July 14, 2013 [Page 13] Internet-Draft RTCP XR Jitter Buffer January 2013 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-05 The following are the major changes to previous version : o Some editorial change changes based on the discussion with Glen and Kevin on the list. A.2. draft-ietf-xrblock-rtcp-xr-jb-03 The following are the major changes to previous version : o Reduce the "jb cfg" to 1-bit based on discussion in the WGLC. o Other editorial change changes aligning with PDV,Delay draft. A.3. draft-ietf-xrblock-rtcp-xr-jb-02 The following are the major changes to previous version : o Add some explanation text in the SDP offer/answer section. o Add some text in applicability section to explain the use to report jitter buffer metrics. o Other editorial change changes aligning with PDV,Delay draft. A.4. draft-ietf-xrblock-rtcp-xr-jb-01 The following are the major changes to previous version : o Outdated reference update o Add one Editor notes to ask clarification on the use of reporting jitter buffer metrics. o Other Editorial changes. A.5. draft-ietf-xrblock-rtcp-xr-jb-00 The following are the major changes to previous version : o Boilerplate updates. Clark, et al. Expires July 14, 2013 [Page 14] Internet-Draft RTCP XR Jitter Buffer January 2013 o references updates o allocate 32 bit field in report block for SSRC o Other editorial changes to get alignment with MONARCH draft. Clark, et al. Expires July 14, 2013 [Page 15] Internet-Draft RTCP XR Jitter Buffer January 2013 Authors' Addresses Alan Clark Telchemy Incorporated 2905 Premiere Parkway, Suite 280 Duluth, GA 30097 USA Email: alan.d.clark@telchemy.com Varun Singh Aalto University School of Electrical Engineering Otakaari 5 A Espoo, FIN 02150 Finland Email: varun@comnet.tkk.fi Qin Wu Huawei 101 Software Avenue, Yuhua District Nanjing, Jiangsu 210012 China Email: sunseawq@huawei.com Clark, et al. Expires July 14, 2013 [Page 16]