[Docs] [txt|pdf] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: (draft-asaeda-xrblock-rtcp-xr-synchronization) 00 01 02 03 04 05 06 07 08 09 RFC 7244

Network Working Group                                          H. Asaeda
Internet-Draft                                                      NICT
Intended status: Standards Track                                   Q. Wu
Expires: August 30, 2014                                        R. Huang
                                                                  Huawei
                                                       February 26, 2014


      RTP Control Protocol (RTCP) Extended Report (XR) Blocks for
           Synchronization Delay and Offset Metrics Reporting
             draft-ietf-xrblock-rtcp-xr-synchronization-09

Abstract

   This document defines two RTP Control Protocol (RTCP) Extended Report
   (XR) Blocks that allow the reporting of synchronization delay and
   offset 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 August 30, 2014.

Copyright Notice

   Copyright (c) 2014 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
   the Trust Legal Provisions and are provided without warranty as



Asaeda, et al.           Expires August 30, 2014                [Page 1]

Internet-Draft              SDO Report Blocks              February 2014


   described in the Simplified BSD License.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Synchronization Delay and Offset Metrics Reporting
           Blocks . . . . . . . . . . . . . . . . . . . . . . . . . .  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.  RTP Flows Initial Synchronization Delay Report Block . . . . .  5
     3.1.  Metric Block Structure . . . . . . . . . . . . . . . . . .  5
     3.2.  Definition of Fields in RTP Flow Initial
           Synchronization Delay Metrics Block  . . . . . . . . . . .  5
   4.  RTP Flows Synchronization Offset Metrics Block . . . . . . . .  7
     4.1.  Metric Block Structure . . . . . . . . . . . . . . . . . .  7
     4.2.  Definition of Fields in RTP Flow General
           Synchronization Offset Metrics Block . . . . . . . . . . .  8
   5.  SDP Signaling  . . . . . . . . . . . . . . . . . . . . . . . .  9
     5.1.  SDP rtcp-xr-attrib Attribute Extension . . . . . . . . . .  9
     5.2.  Offer/Answer Usage . . . . . . . . . . . . . . . . . . . . 10
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 10
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 11
   8.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11
   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
     9.1.  Normative References . . . . . . . . . . . . . . . . . . . 11
     9.2.  Informative References . . . . . . . . . . . . . . . . . . 12
   Appendix A.  Metrics represented using RFC6390 Template  . . . . . 12
   Appendix B.  Change Log  . . . . . . . . . . . . . . . . . . . . . 13
     B.1.  draft-ietf-xrblock-rtcp-xr-syncronization-09 . . . . . . . 14
     B.2.  draft-ietf-xrblock-rtcp-xr-syncronization-08 . . . . . . . 14
     B.3.  draft-ietf-xrblock-rtcp-xr-syncronization-07 . . . . . . . 14
     B.4.  draft-ietf-xrblock-rtcp-xr-syncronization-06 . . . . . . . 14
     B.5.  draft-ietf-xrblock-rtcp-xr-syncronization-05 . . . . . . . 14
     B.6.  draft-ietf-xrblock-rtcp-xr-syncronization-04 . . . . . . . 14
     B.7.  draft-ietf-xrblock-rtcp-xr-syncronization-03 . . . . . . . 14
     B.8.  draft-ietf-xrblock-rtcp-xr-syncronization-02 . . . . . . . 15
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15










Asaeda, et al.           Expires August 30, 2014                [Page 2]

Internet-Draft              SDO Report Blocks              February 2014


1.  Introduction

1.1.  Synchronization Delay and Offset Metrics Reporting Blocks

   This document defines two new block types to augment those defined in
   [RFC3611], for use in a range of RTP applications.

   The first new block type supports reporting of Initial
   Synchronization Delay to establish multimedia session.  Information
   is recorded about time difference between the start of RTP sessions
   and the time the RTP receiver acquires all components of RTP sessions
   in the multimedia session [RFC6051].

   The second new block type supports reporting of the relative
   synchronization offset time of two arbitrary streams (e.g., between
   audio and video streams), with the same RTCP CNAME included in RTCP
   Source description items (SDES) packets [RFC3550].

   These metrics belong to the class of transport level metrics defined
   in [RFC6792].

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 document defines a new Extended Report block for
   use with [RFC3550] and [RFC3611].

1.3.  Performance Metrics Framework

   The RTP Monitoring Architectures [RFC6792] provides guideline for
   reporting block format using RTCP XR.  The new report block described
   in this memo is in compliance with the monitoring architecture
   specified in [RFC6792].

1.4.  Applicability

   When joining each session in layered video sessions [RFC6190] or the
   multimedia session, a receiver may not synchronize playout across the
   multimedia session or layered video session until RTCP Sender Report
   (SR) packets have been received on all components of RTP sessions.
   The component RTP session are referred to as each RTP session for
   each media type in multimedia session or separate RTP session for
   each layer in the layered video session.  For multicast session, the
   initial synchronization delay metric varies with the session
   bandwidth, the number of members, and the number of senders in the
   session.  The RTP flow Initial synchronization delay block defined in
   this document can be used to report such metric, i.e., the initial



Asaeda, et al.           Expires August 30, 2014                [Page 3]

Internet-Draft              SDO Report Blocks              February 2014


   synchronization delay to receive all the RTP streams belonging to the
   same multimedia session or layered video session.  In the absence of
   packet loss, the initial synchronization delay equals to the average
   time taken to receive the first RTCP packet in the RTP session with
   the longest RTCP reporting interval.  In the presence of packet loss,
   the media synchronization should rely on the in-band mapping of RTP
   and NTP-format timestamps [RFC6051] or wait until the reporting
   interval has passed, and the next RTCP SR packet is sent.

   Receivers of the RTP flow initial synchronization delay block could
   use this metric to compare with targets (i.e., Service Level
   Agreement or thresholds of the system) to help ensure the quality of
   real-time application performance.

   In an RTP multimedia session, there can be an arbitrary number of
   streams carried in different RTP sessions, with the same RTCP CNAME.
   These streams may be not synchronized with each other.  For example,
   one audio stream and one video stream belong to the same session, and
   the audio stream is transmitted lagging behind video stream for
   multiple tens of milliseconds [TR-126].  The RTP Flows
   Synchronization Offset block can be used to report such
   synchronization offset between video stream and audio stream.  This
   block is also applied to the case where an RTP session can contain
   media streams with media from multiple media types.  The metrics
   defined in the RTP flows synchronization Offset block can be used by
   the network manager for trouble shooting and dealing with user
   experience issues.


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].

   In addition, the following terms are defined:

   Initial Synchronization Delay:

      A multimedia session comprises a set of concurrent RTP sessions
      among a common group of participants, using one RTP session for
      each media type.  The initial synchronization Delay is the average
      time for receiver to synchronize all components of a multimedia
      session [RFC6051].





Asaeda, et al.           Expires August 30, 2014                [Page 4]

Internet-Draft              SDO Report Blocks              February 2014


   Synchronization Offset:

      Synchronization between two media streams must be maintained to
      ensure satisfactory Quality of Experience (QoE).  Two media
      streams can be of the same or different media type belonging to
      one RTP session or in different media types belonging to one
      multimedia session.  The Synchronization Offset is the relative
      time difference of the two media streams that need to be
      synchronized.



3.  RTP Flows Initial Synchronization Delay Report Block

   This block is sent by RTP receivers and reports Initial
   synchronization delay beyond the information carried in the standard
   RTCP packet format.  Information is recorded about time difference
   between the start of multimedia session and the time when the RTP
   receiver acquires all components of RTP sessions [RFC6051] measured
   at the receiving end of RTP stream.

   This block needs only be exchanged occasionally, for example sent
   once at the start of RTP session.

3.1.  Metric Block Structure

   The RTP Flows Initial Synchronization Delay Report Block has the
   following format:

       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=RFISD   |   Reserved    |         Block length=2        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                      SSRC of Source                           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |               Initial Synchronization Delay                   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 Figure 1: Report Block Structure

3.2.  Definition of Fields in RTP Flow Initial Synchronization Delay
      Metrics Block








Asaeda, et al.           Expires August 30, 2014                [Page 5]

Internet-Draft              SDO Report Blocks              February 2014


   Block type (BT): 8 bits

      The RTP Flows Initial Synchronization Delay Report Block is
      identified by the constant <RFISD>.

      [Note to RFC Editor: please replace RFISD with the IANA provided
      RTCP XR block type for this block.]

   Reserved: 8 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
      ignored by the receiver.

   Block length: 16 bits

      The constant 2, in accordance with the definition of this field in
      Section 3 of RFC 3611 [RFC3611].

   SSRC of source: 32 bits

      The SSRC of the media source SHALL be set to the value of the SSRC
      identifier carried in any arbitrary component of RTP sessions
      belonging to the same multimedia session.

   Initial Synchronization Delay: 32 bits

      The average delay, expressed in units of 1/65536 seconds, from the
      beginning of multimedia session [RFC6051] to the time when RTCP
      packets are received on all of the components RTP sessions.  It is
      recommended that the beginning of multimedia session is chosen as
      the time when the receiver has joined the first RTP session of the
      multimedia session.  The value of the initial synchronization
      delay is calculated based on received RTCP SR packets or the RTP
      header extension containing in-band mapping of RTP and NTP-format
      timestamps [RFC6051].  If there is no packet loss, the initial
      synchronization delay is expected to be equal to the average time
      taken to receive the first RTCP packet in the RTP session with the
      longest RTCP reporting interval or the average time taken to
      receive the first RTP header extension containing in-band mapping
      of RTP and NTP-format timestamps.

      If the measurement is unavailable, the value of this field with
      all bits set to 1 MUST be reported.







Asaeda, et al.           Expires August 30, 2014                [Page 6]

Internet-Draft              SDO Report Blocks              February 2014


4.  RTP Flows Synchronization Offset Metrics Block

   In the RTP multimedia sessions or one RTP session, there can be an
   arbitrary number of Media streams and each media stream (e.g., audio
   stream or video stream) is sent in a separate RTP stream.  In case of
   one RTP session, each media stream or each medium uses different
   SSRC.  The receiver associates RTP streams to be synchronized by
   means of RTCP CNAME contained in the RTCP Source Description (SDES)
   packets [RFC3550].

   This block is sent by RTP receivers and reports synchronization
   offset of two arbitrary RTP streams that needs to be synchronized in
   the RTP multimedia session.  Information is recorded about the
   relative average time difference between two arbitrary RTP streams
   (one is reporting stream, the other is reference stream) with the
   same CNAME and measured at the receiving end of RTP stream.  In order
   to tell what the offset of reporting stream is relative to, the block
   for reference stream with synchronization offset of zero should be
   reported.

   Instances of this Block refer by Synchronization source (SSRC) to the
   separate auxiliary Measurement Information block [RFC6776] which
   describes measurement periods in use (see [RFC6776] section 4.2).
   This metrics block relies on the measurement period 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 period is not received in the
   same compound RTCP packet as this Block, this Block MUST be
   discarded.

4.1.  Metric Block Structure

   The RTP Flow General Synchronization Offset Report Block has the
   following format:

       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=RFSO    | I | Reserved  |         Block length=3        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        SSRC of source                         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         Synchronization Offset, most significant word         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         Synchronization Offset, least significant word        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 Figure 2: Report Block Structure



Asaeda, et al.           Expires August 30, 2014                [Page 7]

Internet-Draft              SDO Report Blocks              February 2014


4.2.  Definition of Fields in RTP Flow General Synchronization Offset
      Metrics Block

   Block type (BT): 8 bits

      The RTP Flow General Synchronization Offset Report Block is
      identified by the constant <RFSO>.

      [Note to RFC Editor: please replace RFSO 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 Burst/Gap Discard
      Summary Statistics metrics are Sampled, Interval or Cumulative
      metrics:

         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.


      In this document, the value I=00 is the reserved value and MUST
      NOT be used.  If the value I=00 is received, then the XR block
      MUST be ignored by the receiver.

   Reserved: 6 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.

   Block length: 16 bits

      The constant 3, in accordance with the definition of this field in
      Section 3 of RFC 3611 [RFC3611].

   SSRC of Source: 32 bits

      The SSRC of the media source SHALL be set to the value of the SSRC
      identifier of the reporting RTP stream to which the XR relates.






Asaeda, et al.           Expires August 30, 2014                [Page 8]

Internet-Draft              SDO Report Blocks              February 2014


   Synchronization Offset: 64 bits

      The synchronization offset of the reporting RTP stream relative to
      the reference stream with the same CNAME.  The calculation of
      Synchronization Offset is similar to Difference D calculation in
      the RFC3550.  That is to say, if Si is the NTP timestamp from the
      reporting RTP packet i, and Ri is the time of arrival in NTP
      timestamp units for reporting RTP packet i, Sj is the NTP
      timestamp from the reference RTP packet j, and Rj is the time of
      arrival in NTP timestamp units for reference RTP packet j, then
      the value of the synchronization offset D may be expressed as

         D(i,j) = (Rj - Ri) - (Sj - Si) = (Rj - Sj) - (Ri - Si)

      If in-band delivery of NTP-format timestamps is supported
      [RFC6051], Si and Sj should be obtained directly from the RTP
      packets where NTP timestamps are available.  If not, Si and Sj
      should be calculated from their corresponding RTP timestamps.  The
      value of the synchronization offset is represented using a 64-bit
      signed NTP-format timestamp as defined in [RFC5905], which is 64-
      bit signed fixed-point number with the integer part in the first
      32 bits and the fractional part in the last 32 bits.  A positive
      value of the synchronization offset means that the reporting
      stream leads before the reference stream, while a negative one
      means the reporting stream lags behind the reference stream.  The
      synchronization offset of zero means the stream is the reference
      stream.

      If the measurement is unavailable, the value of this field with
      all bits set to 1 MUST be reported.


5.  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.

5.1.  SDP rtcp-xr-attrib Attribute Extension

   Two new parameters are defined for the two 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]:






Asaeda, et al.           Expires August 30, 2014                [Page 9]

Internet-Draft              SDO Report Blocks              February 2014


   xr-format = xr-rfisd-block
             / xr-rfso-block

   xr-rfisd-block = "rtp-flow-init-syn-delay"
   xr-rfso-block = "rtp-flow-syn-offset"

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

5.2.  Offer/Answer Usage

   When SDP is used in offer-answer context, the SDP Offer/Answer usage
   defined in [RFC3611] applies.


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 two new block type values in the RTCP XR Block
   Type Registry:

      Name:       RFISD
      Long Name:  RTP Flows Initial Synchronization Delay
      Value       <RFISD>
      Reference:  Section 3

      Name:       RFSO
      Long Name:  RTP Flows Synchronization Offset Metrics Block
      Value       <RFSO>
      Reference:  Section 4


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

      *  "rtp-flow-init-syn-delay "
      *  "rtp-flow-syn-offset"

   The contact information for the registrations is:

         RAI Area Directors







Asaeda, et al.           Expires August 30, 2014               [Page 10]

Internet-Draft              SDO Report Blocks              February 2014


         <rai-ads@tools.ietf.org>


7.  Security Considerations

   When using Secure RTP [RFC3711], or other media layer security,
   reporting accurate synchronisation offset information can expose some
   details about the timing of the cryptographic operations that are
   used to protect the media.  There is a possibility that this timing
   information might enable a side-channel attack on the encryption.
   For environments where this attack is a concern, implementations need
   to take care to ensure cryptographic processing and media compression
   take the same amount of time irrespective of the media content, to
   avoid the potential attack.

   Besides this, it is believed that this RTCP XR block 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, Kevin Gross, Jing Zhao, Fernando
   Boronat Segui, Mario Montagud Climent, Youqing Yang, Wenxiao Yu and
   Yinliang Hu,Jonathan Lennox, Stephen Farrel 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.

   [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.

   [RFC3711]  Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K.
              Norrman, "The Secure Real-time Transport Protocol (SRTP)",
              RFC 3711, March 2004.

   [RFC4566]  Handley, M., Jacobson, V., and C. Perkins, "SDP: Session



Asaeda, et al.           Expires August 30, 2014               [Page 11]

Internet-Draft              SDO Report Blocks              February 2014


              Description Protocol", RFC 4566, July 2006.

   [RFC5234]  Crocker, D. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", STD 68, RFC 5234, January 2008.

   [RFC5905]  Mills, D., Martin, J., Burbank, J., and W. Kasch, "Network
              Time Protocol Version 4: Protocol and Algorithms
              Specification", RFC 5905, June 2010.

   [RFC6051]  Perkins, C. and T. Schierl, "Rapid Synchronisation of RTP
              Flows", RFC 6051, November 2010.

   [RFC6190]  Wenger, S., Wang, Y., Schierl, T., and A. Eleftheriadis,
              "RTP Payload Format for Scalable Video Coding", RFC 6190,
              May 2011.

   [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, "Guidelines for Considering New
              Performance Metric Development", RFC 6390, October 2011.

   [RFC6792]  Wu, Q., "Guidelines for Use of the RTP Monitoring
              Framework", RFC 6792, November 2012.

   [TR-126]   BBF Forum, "Triple-play Services Quality of Experience
              (QoE) Requirements", December 2006.

   [Y.1540]   ITU-T, "ITU-T Rec. Y.1540, IP packet transfer and
              availability performance parameters", November 2007.


Appendix A.  Metrics represented using RFC6390 Template

   RFC EDITOR NOTE: please change XXXX in [RFCXXXX] by the new RFC
   number, when assigned.

   a.  Initial Synchronization Delay Metric

       *  Metric Name: RTP Initial Synchronization Delay

       *  Metric Description: See Section 2.1,Initial Synchronization
          Delay term [RFCXXXX].






Asaeda, et al.           Expires August 30, 2014               [Page 12]

Internet-Draft              SDO Report Blocks              February 2014


       *  Method of Measurement or Calculation: See section 3.2, Initial
          Synchronization Delay definition [RFCXXXX].

       *  Units of Measurement: See section 3.2, Initial Synchronization
          Delay definition [RFCXXXX].

       *  Measurement Point(s) with Potential Measurement Domain: See
          section 3, 1st paragraph [RFCXXXX].

       *  Measurement Timing: See section 3, 2nd paragraph [RFCXXXX] for
          measurement timing.

       *  Use and applications: See section 1.4 [RFCXXXX].

       *  Reporting model: See RFC3611.

   b.  Synchronization Offset Metric

       *  Metric Name: RTP Synchronization Offset Delay

       *  Metric Description: See Section 2.1, Synchronization Offset
          term [RFCXXXX].

       *  Method of Measurement or Calculation: See section 4.2, Initial
          Synchronization Delay definition [RFCXXXX].

       *  Units of Measurement: See section 4.2, Initial Synchronization
          Delay definition [RFCXXXX].

       *  Measurement Point(s) with Potential Measurement Domain: See
          section 4, 2nd paragraph [RFCXXXX].

       *  Measurement Timing: See section 4, 3rd paragraph [RFCXXXX] for
          measurement timing and section 4.2 [RFCXXXX] for Interval
          Metric flag.

       *  Use and applications: See section 1.4 [RFCXXXX].

       *  Reporting model: See RFC3611.



Appendix B.  Change Log

   Note to the RFC-Editor: please remove this section prior to
   publication as an RFC.





Asaeda, et al.           Expires August 30, 2014               [Page 13]

Internet-Draft              SDO Report Blocks              February 2014


B.1.  draft-ietf-xrblock-rtcp-xr-syncronization-09

   The following are the major changes compared to previous version:

      Some Editorial changes based on IESG Review comments.

B.2.  draft-ietf-xrblock-rtcp-xr-syncronization-08

   The following are the major changes compared to previous version:

      Some Editorial changes based on Gen-Art Reviewer comments.

B.3.  draft-ietf-xrblock-rtcp-xr-syncronization-07

   The following are the major changes compared to previous version:

      Minor Editorial changes.

B.4.  draft-ietf-xrblock-rtcp-xr-syncronization-06

   The following are the major changes compared to previous version:

      Some Editorial changes.

B.5.  draft-ietf-xrblock-rtcp-xr-syncronization-05

   The following are the major changes compared to previous version:

      Editorial changes and typo fixed.

B.6.  draft-ietf-xrblock-rtcp-xr-syncronization-04

   The following are the major changes compared to previous version:

      Additional text to clarify on how to distinguish report stream
      from reference stream.
      Other Editorial changes.

B.7.  draft-ietf-xrblock-rtcp-xr-syncronization-03

   The following are the major changes compared to previous version:

      Remove the need to signal the reference source in the
      synchronisation offset metrics RTCP XR report.
      Apply RFC6390 template to metrics in the appendix.
      Other editorial changes to get inline with other XRBLOCK drafts.





Asaeda, et al.           Expires August 30, 2014               [Page 14]

Internet-Draft              SDO Report Blocks              February 2014


B.8.  draft-ietf-xrblock-rtcp-xr-syncronization-02

   The following are the major changes compared to previous version:

      Editorial change based on comments raised on the list and in the
      IETF85 meeting


Authors' Addresses

   Hitoshi Asaeda
   National Institute of Information and Communications Technology
   4-2-1 Nukui-Kitamachi
   Koganei, Tokyo  184-8795
   Japan

   Email: asaeda@nict.go.jp


   Qin Wu
   Huawei Technologies Co., Ltd.
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   Email: bill.wu@huawei.com


   Rachel Huang
   Huawei Technologies Co., Ltd.
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   Email: Rachel@huawei.com
















Asaeda, et al.           Expires August 30, 2014               [Page 15]


Html markup produced by rfcmarkup 1.108, available from http://tools.ietf.org/tools/rfcmarkup/