Audio/Video Transport Working Group                             A. Clark
Internet-Draft                                                  Telchemy
Intended status: Standards Track                                V. Singh
Expires: April 20, 2013                                 Aalto University
                                                                   Q. Wu
                                                                  Huawei
                                                        October 17, 2012


RTP Control Protocol (RTCP) Extended Report (XR) Block for Jitter Buffer
                            Metric Reporting
                  draft-ietf-xrblock-rtcp-xr-jb-01.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
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   This Internet-Draft will expire on April 20, 2013.

Copyright Notice

   Copyright (c) 2012 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
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   include Simplified BSD License text as described in Section 4.e of



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   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.  Jitter Buffer Metrics Block  . . . . . . . . . . . . . . . . .  4
     2.1.  Report Block Structure . . . . . . . . . . . . . . . . . .  4
     2.2.  Definition of Fields in Jitter Buffer Metrics Block  . . .  4
   3.  SDP Signaling  . . . . . . . . . . . . . . . . . . . . . . . .  7
   4.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  8
     4.1.  New RTCP XR Block Type value . . . . . . . . . . . . . . .  8
     4.2.  New RTCP XR SDP Parameter  . . . . . . . . . . . . . . . .  8
     4.3.  Contact information for registrations  . . . . . . . . . .  8
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . .  9
   6.  Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 10
   7.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 11
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
     8.1.  Normative References . . . . . . . . . . . . . . . . . . . 12
     8.2.  Informative References . . . . . . . . . . . . . . . . . . 12
   Appendix A.  Change Log  . . . . . . . . . . . . . . . . . . . . . 13
     A.1.  draft-ietf-xrblock-rtcp-xr-jb-01 . . . . . . . . . . . . . 13
     A.2.  draft-ietf-xrblock-rtcp-xr-jb-00 . . . . . . . . . . . . . 13
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14






















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1.  Introduction

1.1.  Jitter Buffer Metrics Block

   This draft 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 terminal metrics
   defined in [MONARCH].

   Instances of this Metrics Block refer by SSRC to the separate
   auxiliary Measurement Information block [MEASI] 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]
   defined an extensible structure for reporting using an RTCP Extended
   Report (XR).  This draft 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 [MONARCH] provides guideline for reporting
   block format using RTCP XR.  Metrics described in this draft are in
   accordance with the guidelines in [RFC6390][MONARCH].

1.4.  Applicability

   These metrics are applicable to a range of RTP applications.

   Editor Note: What the use is for reporting jitter buffer metrics?













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2.  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 [MEASI]
   which contains measurement intervals.  This metric 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 metric block, this metric block should be discarded.

2.1.  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 |jb cfg |rsv|       block length=3          |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                           SSRC of Source                      |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |          JB nominal           |         JB maximum            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |     JB high water mark        |      JB low water mark        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                     Figure 1: Report Block Structure

2.2.  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, that is, whether the
      reported values applies to the most recent measurement interval
      duration between successive metrics reports (I=10) (the Interval



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      Duration) or to the accumulation period characteristic of
      cumulative measurements (I=11) (the Cumulative Duration) or is a
      sampled instantaneous value (I=01) (Sampled Value).


   Jitter Buffer Configuration (jb cfg): 4 bits

      This field is used to identify the jitter buffer method in use at
      the receiver, according to the following code:

         bits 014-011

            0 = Fixed jitter buffer

            1 = Adaptive jitter buffer

            Other values reserved


   Reserved (rsv): 2 bits

      These bits are reserved.  They SHOULD be set to zero by senders
      and MUST be ignored by receivers.


   Block Length: 16 bits

      The length of this report block in 32-bit words, minus one and
      MUST be set to 3, in accordance with the definition of this field
      in [RFC3611].  The block MUST be discarded if the block length is
      set to a different value.


   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.  This parameter MUST be provided for
      both fixed and adaptive jitter buffer implementations.

      If the measured value exceeds 0xFFFD, the value 0xFFFE SHOULD be
      reported to indicate an over-range measurement.  If the
      measurement is unavailable, the value 0xFFFF SHOULD be reported.








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   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.  In simple queue implementations this may correspond
      to the nominal size.  In adaptive jitter buffer implementations,
      this value may dynamically.  This parameter MUST be provided for
      both fixed and adaptive jitter buffer implementations.

      If the measured value exceeds 0xFFFD, the value 0xFFFE SHOULD be
      reported to indicate an over-range measurement.  If the
      measurement is unavailable, the value 0xFFFF SHOULD 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.

      If the measured value exceeds 0xFFFD, the value 0xFFFE SHOULD be
      reported to indicate an over-range measurement.  If the
      measurement is unavailable, the value 0xFFFF SHOULD 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.

      If the measured value exceeds 0xFFFD, the value 0xFFFE SHOULD be
      reported to indicate an over-range measurement.  If the
      measurement is unavailable, the value 0xFFFF SHOULD be reported.

















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3.  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 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"






































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4.  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].

4.1.  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.]

4.2.  New RTCP XR SDP Parameter

   This document also registers a new parameter "jitter-bfr" in the
   "RTCP XR SDP Parameters Registry".

4.3.  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























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5.  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.












































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6.  Contributors

   Geoff Hunt wrote the initial draft of this document.
















































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7.  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, and Hideaki Yamada.











































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8.  References

8.1.  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.

8.2.  Informative References

   [MEASI]    Hunt, G., "Measurement Identity and information Reporting
              using SDES item and XR Block",
              ID draft-ietf-xrblock-rtcp-xr-meas-identity-10,
              August 2012.

   [MONARCH]  Hunt, G., "Monitoring Architectures for RTP",
              ID draft-ietf-avtcore-monarch-22, September 2012.

   [RFC6390]  Clark, A. and B. Claise, "Framework for Performance Metric
              Development", RFC 6390, October 2011.























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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-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.2.  draft-ietf-xrblock-rtcp-xr-jb-00

   The following are the major changes to previous version :

   o  Boilerplate updates.

   o  references updates

   o  allocate 32 bit field in report block for SSRC

   o  Other editorial changes to get alignment with MONARCH draft.
























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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























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