[Docs] [txt|pdf|xml|html] [Tracker] [Email] [Diff1] [Diff2] [Nits]

Versions: 00 01 02 03 04 05 06 07 08

Network Working Group                                              Q. Wu
Internet-Draft                                                    Huawei
Intended status: Standards Track                                 G. Zorn
Expires: November 17, 2011                                   Network Zen
                                                               R. Schott
                                           Deutsche Telekom Laboratories
                                                                  K. Lee
                                                           China Telecom
                                                            May 16, 2011


         RTCP XR Blocks for multimedia quality metric reporting
             draft-wu-xrblock-rtcp-xr-quality-monitoring-02

Abstract

   This document defines an RTCP XR Report Block and associated SDP
   parameters that allows the reporting of multimedia quality metrics
   for use in 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 November 17, 2011.

Copyright Notice

   Copyright (c) 2011 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



Wu, et al.              Expires November 17, 2011               [Page 1]


Internet-Draft        RTCP XR Quality Report Blocks             May 2011


   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.

   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008.  The person(s) controlling the copyright in some of this
   material may not have granted the IETF Trust the right to allow
   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
   outside the IETF Standards Process, and derivative works of it may
   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
     2.1.  Standards Language  . . . . . . . . . . . . . . . . . . . . 3
   3.  Applicability . . . . . . . . . . . . . . . . . . . . . . . . . 3
   4.  Synthetical Multimedia Quality Metrics Block  . . . . . . . . . 4
     4.1.  Metric Block Structure  . . . . . . . . . . . . . . . . . . 4
     4.2.  Definition of Fields in Multimedia Quality Metrics
           Block . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
   5.  SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . . 6
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
   7.  Security Considerations . . . . . . . . . . . . . . . . . . . . 7
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 7
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 7
     9.1.  Normative References  . . . . . . . . . . . . . . . . . . . 7
     9.2.  Informative References  . . . . . . . . . . . . . . . . . . 8
   Appendix A.  Change Log . . . . . . . . . . . . . . . . . . . . . . 9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 9















Wu, et al.              Expires November 17, 2011               [Page 2]


Internet-Draft        RTCP XR Quality Report Blocks             May 2011


1.  Introduction

   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 multimedia quality using
   one of several standard metrics.

   The metrics belong to the class of application level metrics defined
   in [MONARCH] (work in progress).


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].


3.  Applicability

   The Multimedia Quality Metrics Report Block can be used in any real-
   time AV application.

   The factors that affect real-time AV application quality can be split
   into two categories.  The first category consists of transport-
   dependent factors such as packet loss, delay and jitter (which also
   translates into losses in the playback buffer).  The factors in the
   second category are application-specific factors that affect real
   time application (e.g., video) quality and are sensitivity to network
   errors.  These factors can be but not limited to video codec and loss
   recovery technique, coding bit rate, packetization scheme, and
   content characteristics.

   Compared with application-specific factors, the transport-dependent
   factors sometimes are not sufficient to measure real time data
   quality, since the ability to analyze the real time data in the
   application layer provides quantifiable measurements for subscriber
   Quality of Experience (QoE) that may not be captured in the
   transmission layers or from the RTP layer down.  In a typical
   scenario, monitoring of the transmission layers can produce
   statistics suggesting that quality is not an issue, such as the fact
   that network jitter is not excessive.  However, problems may occur in
   the service layers leading to poor subscriber QoE.  Therefore
   monitoring using only network-level measurements may be insufficient
   when application layer content quality is required.



Wu, et al.              Expires November 17, 2011               [Page 3]


Internet-Draft        RTCP XR Quality Report Blocks             May 2011


   In order to provide accurate measures of real time application
   quality when transporting real time contents across a network, the
   synthentical multimedia quality Metrics is highly required which can
   be conveyed in the RTCP XR packets[RFC3611] and may have the
   following three benefits:

   o  Tuning the content encoder algorithm to satisfy real time data
      quality requirements
   o  Determining which system techniques to use in a given situation
      and when to switch from one technique to another as system
      parameters change
   o  Verifying the continued correct operation of an existing system


4.  Synthetical Multimedia Quality Metrics Block

   This block reports the multimedia application performance or quality
   metrics beyond the information carried in the standard RTCP packet
   format.  Information is recorded about multimedia application QoE
   metric which is expressed as a MOS ("Mean Opinion Score"), MOS is on
   a scale from 1 to 5, in which 5 represents excellent and 1 represents
   unacceptable.  MOS scores are usually obtained using subjective
   testing or using objective algorithm to estimate the multimedia
   quality.  However Subjective testing is not suitable for measuring
   the multimedia quality since the results may vary from test to test.
   Therefore using objective algorithm to calculate MOS scores is
   recommended.  ITU-T recommendation [G.1082][P.NAMS][P.NBAMS] defines
   a methodology for verifying the performance of QoE estimation
   algorithms for video and audio.  Hence this document recommends
   vendors and implementers to use International Telecommunication Union
   (ITU)-specified methodologies to measure parameters when possible.


4.1.  Metric Block Structure

   The report block contents are dependent upon a series of flag bits
   carried in the first part of the header.  Not all parameters need to
   be reported in each block.  Flags indicate which are and which are
   not reported.  The fields corresponding to unreported parameters MUST
   be present, but are set to zero.  The receiver MUST ignore any
   Perceptual Quality Metrics Block with a non-zero value in any field
   flagged as unreported.

   The Synthetical Multimedia Quality Metrics Block has the following
   format:






Wu, et al.              Expires November 17, 2011               [Page 4]


Internet-Draft        RTCP XR Quality Report Blocks             May 2011


       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=TBD    |I| tag |   MC  |        block length           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        SSRC of source                         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                         MOS Value                             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

4.2.  Definition of Fields in Multimedia Quality Metrics Block

   Block type (BT): 8 bits

      The Perceptual Quality Metrics Block is identified by the constant
      <SMQM>.

   Interval Metric flag (I): 1 bit

      This field is used to indicate whether the Basic Loss/Discard
      metrics are Interval or Cumulative metrics, that is, whether the
      reported values applies to the most recent measurement interval
      duration between successive metrics reports (I=1) (the Interval
      Duration) or to the accumulation period characteristic of
      cumulative measurements (I=0) (the Cumulative Duration).

   Measurement Identifier association (tag): 3 bits

      This field is used to identify the Measurement Identifier block
      [MEASIDENT] which describes this measurement.

   MoS Class (MC): 4 bits

      This field is used to indicate the MOS type to be reported.  The
      MOS type is defined as follows:
         0000 MOS-A - Audio Quality MOS [G.107][P.564].
         0001 MOS-V - Video Quality MOS [P.NAMS][P.NBAMS].
         0010 MOS-AV - Audio-Video Quality MOS[P.NAMS][P.NBAMS].
         0100~1111 - Reserved

   Rsd.: 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
      MUST be ignored by the receiver.






Wu, et al.              Expires November 17, 2011               [Page 5]


Internet-Draft        RTCP XR Quality Report Blocks             May 2011


   SSRC of source: 32 bits

      As defined in Section 4.1 of [RFC3611].

   MOS Value: Variable Length

      The estimated mean opinion score for Audio Qulity, Video Quality
      or Audio-Video quality is defined as including the effects of
      delay and other effects that would affect Audio-Video quality
      [G.1082][P.NAMS][P.NBAMS].  It is expressed as an integer in the
      range 10 to 50, corresponding to MOS x 10, as for MOS.  A value of
      127 indicates that this parameter is unavailable.  Values other
      than 127 and the valid range defined above MUST NOT be sent and
      MUST be ignored by the receiving system.



5.  SDP Signaling

   One new parameter is defined for the six report blocks defined in
   this document to be used with Session Description Protocol (SDP)
   [RFC4566] using the Augmented Backus-Naur Form (ABNF) [RFC5234].
   They have the following syntax within the "rtcp-xr" attribute
   [RFC3611]:

   rtcp-xr-attrib =  "a=rtcp-xr:"
                     [xr-format *(SP xr-format)] CRLF
         xr-format = multimedia-quality-metrics
            multimedia-quality-metrics = "multimedia-quality-metrics"
                                  ["=" stat-flag *("," stat-flag)]
               stat-flag = "Interval Metrics"
                            /"Cumulative metrics"

   Refer to Section 5.1 of RFC 3611 [RFC3611] for a detailed description
   and the full syntax of the "rtcp-xr" attribute.


6.  IANA Considerations

   New report block types for RTCP XR are subject to IANA registration.
   For general guidelines on IANA allocations for RTCP XR, refer to
   Section 6.2 of [RFC3611].

   This document assigns one new block type value in the RTCP XR Block
   Type Registry:






Wu, et al.              Expires November 17, 2011               [Page 6]


Internet-Draft        RTCP XR Quality Report Blocks             May 2011


      Name:       SMQM
      Long Name:  Synthetical Multimedia Quality Metric
      Value       <SMQM>
      Reference:  Section 4

   This document also registers one new SDP [RFC4566] parameter for the
   "rtcp-xr" attribute in the RTCP XR SDP Parameters Registry:

      *  "multimedia-quality-metrics"

   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 report blocks proposed in this document introduces no
   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 and Yinliang
   Hu 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.

   [RFC2250]  Hoffman, D., Fernando, G., Goyal, V., and M. Civanlar,
              "RTP Payload Format for MPEG1/MPEG2 Video", RFC 2250,
              January 1998.

   [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,



Wu, et al.              Expires November 17, 2011               [Page 7]


Internet-Draft        RTCP XR Quality Report Blocks             May 2011


              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.

9.2.  Informative References

   [DSLF]     Rahrer, T., Ed., Fiandra, Ed., and Wright, Ed., "Triple-
              play Services Quality of Experience (QoE) Requirements",
              DSL Forum Technical Report TR-126, December 2006.

   [G.107]    ITU-T, "The E Model, a computational model for use in
              transmission planning", ITU-T Recommendation G.107,
              April 2009.

   [G.1082]   ITU-T, "Measurement-based methods for improving the
              robustness of IPTV performance", ITU-T
              Recommendation G.1082, April 2009.

   [IEEE]     IEEE, "Human Perception of Jitter and Media
              Synchronization", IEEE Journal on Selected Areas in
              Communications Vol. 14, No. 1, January 1996.

   [MEASIDENT]
              Hunt, G. and A. Clark, "RTCP XR Measurement Identifier
              Block", ID draft-ietf-avt-rtcp-xr-meas-identity-02,
              May 2009.

   [MONARCH]  Wu, Q., "Monitoring Architectures for RTP",
              ID draft-ietf-avtcore-monarch-00, April 2011.

   [P.564]    ITU-T, "Conformance testing for narrowband Voice over IP
              transmission quality assessment models", ITU-T
              Recommendation P.564, July 2006.

   [P.NAMS]   ITU-T, "Non-intrusive parametric model for the Assessment
              of performance of Multimedia Streaming", ITU-T
              Recommendation P.NAMS, November 2009.

   [P.NBAMS]  ITU-T, "non-intrusive bit-stream model for assessment of
              performance of multimedia streaming", ITU-T
              Recommendation P.NBAMS, November 2009.

   [PMOL]     Clark, A., "Framework for Performance Metric Development",
              ID draft-ietf-pmol-metrics-framework-08, January 2011.



Wu, et al.              Expires November 17, 2011               [Page 8]


Internet-Draft        RTCP XR Quality Report Blocks             May 2011


Appendix A.  Change Log

   This version focuses on multimedia quality metrics and separated
   other metrics block as independent documents.


Authors' Addresses

   Qin Wu
   Huawei
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   Email: sunseawq@huawei.com


   Glen Zorn
   Network Zen
   77/440 Soi Phoomjit, Rama IV Road
   Phra Khanong, Khlong Toie
   Bangkok  10110
   Thailand

   Phone: +66 (0) 87 502 4274
   Email: gwz@net-zen.net


   Roland Schott
   Deutsche Telekom Laboratories
   Deutsche-Telekom-Allee 7
   Darmstadt  64295
   Germany

   Email: Roland.Schott@telekom.de


   Kai Lee
   China Telecom
   China Telecom Beijing Research Institute

   Email: leekai@ctbri.com.cn









Wu, et al.              Expires November 17, 2011               [Page 9]


Html markup produced by rfcmarkup 1.129b, available from https://tools.ietf.org/tools/rfcmarkup/