One document matched: draft-ietf-avtcore-monarch-04.xml


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  <front>
    <title abbrev="RTP Monitoring Architectures">Monitoring Architectures for
    RTP</title>

    <author fullname="Qin Wu" initials="Q." role="editor" surname="Wu">
      <organization>Huawei</organization>

      <address>
        <postal>
          <street>101 Software Avenue, Yuhua District</street>

          <city>Nanjing</city>

          <region>Jiangsu</region>

          <code>210012</code>

          <country>China</country>
        </postal>

        <email>sunseawq@huawei.com</email>
      </address>
    </author>

    <author fullname="Geoff Hunt" initials="G." surname="Hunt">
      <organization>Unaffiliated</organization>

      <address>
        <email>r.geoff.hunt@gmail.com</email>
      </address>
    </author>

    <author fullname="Philip Arden" initials="P.J." surname="Arden">
      <organization abbrev="BT">BT</organization>

      <address>
        <postal>
          <street>Orion 3/7 PP4</street>

          <street>Adastral Park</street>

          <street>Martlesham Heath</street>

          <city>Ipswich</city>

          <region>Suffolk</region>

          <code>IP5 3RE</code>

          <country>United Kingdom</country>
        </postal>

        <phone>+44 1473 644192</phone>

        <email>philip.arden@bt.com</email>
      </address>
    </author>

    <date month="August" year="2011" />

    <area>Real-time Applications and Infrastructure Area</area>

    <workgroup>Audio/Video Transport Working Group</workgroup>

    <keyword>RFC</keyword>

    <keyword>Request for Comments</keyword>

    <keyword>I-D</keyword>

    <keyword>Internet-Draft</keyword>

    <keyword>Real Time Control Protocol</keyword>

    <abstract>
      <t>This memo proposes an architecture for extending RTCP with a new RTCP
      XR (RFC3611) block type to report new metrics regarding media
      transmission or reception quality, as proposed in RFC5968. This memo
      suggests that a new block should contain a single metric or a small
      number of metrics relevant to a single parameter of interest or concern,
      rather than containing a number of metrics which attempt to provide full
      coverage of all those parameters of concern to a specific application.
      Applications may then "mix and match" to create a set of blocks which
      covers their set of concerns. Where possible, a specific block should be
      designed to be re-usable across more than one application, for example,
      for all of voice, streaming audio and video.</t>
    </abstract>
  </front>

  <middle>
    <section anchor="intro" title="Introduction">
      <t>As more users and subscribers rely on real time application services,
      uncertainties in the performance and availability of these services are
      driving the need to support new standard methods for gathering
      performance metrics from RTP applications. These rapidly emerging
      standards, such as RTCP XR <xref target="RFC3611"></xref>and other RTCP
      extension to Sender Reports(SR), Receiver Reports (RR) <xref
      target="RFC3550"></xref>are being developed for the purpose of
      collecting and reporting performance metrics from endpoint devices that
      can be used to correlate the metrics, provide end to end service
      visibility and measure and monitor QoE.</t>

      <t>However the proliferation of RTP/RTCP specific metrics for transport
      and application quality monitoring has been identified as a potential
      problem for RTP/RTCP interoperability, which attempt to provide full
      coverage of all those parameters of concern to a specific application.
      Since different applications layered on RTP may have some monitoring
      requirements in common, therefore these metrics should be satisfied by a
      common design.</t>

      <t>The objective of this document is to define an extensible RTP
      monitoring framework to provide a small number of re-usable QoS/QoE
      metrics which facilitate reduced implementation costs and help maximize
      inter-operability. <xref target="RFC5968"></xref> has stated that, where
      RTCP is to be extended with a new metric, the preferred mechanism is by
      the addition of a new RTCP XR <xref target="RFC3611"></xref> block. This
      memo assumes that any requirement for a new metric to be transported in
      RTCP will use a new RTCP XR block.</t>
    </section>

    <section title="Requirements notation">
      <t>This memo is informative and as such contains no normative
      requirements.</t>

      <t>In addition, the following terms are defined:</t>

      <t><list style="hanging">
          <t hangText="Transport level metrics"><vspace blankLines="1" />A set
          of metrics which characterise the three transport impairments of
          packet loss, packet delay, and packet delay variation. These metrics
          should be usable by any application which uses RTP transport.<vspace
          blankLines="1" /></t>

          <t hangText="Application level metrics"><vspace
          blankLines="1" />Metrics relating to QoE related parameters. These
          metrics are measured at the application level and focus on quality
          of content rather than network parameters. One example of such
          metrics is the Multimedia Quality Metric specified in <xref
          target="MQ"></xref>. <vspace blankLines="1" /></t>

          <t hangText="End System metrics"><vspace blankLines="1" />Metrics
          relating to the way a terminal deals with transport impairments
          affecting the incident RTP stream. These may include de-jitter
          buffering, packet loss concealment, and the use of redundant streams
          (if any) for correction of error or loss.<vspace
          blankLines="1" /></t>
        </list></t>
    </section>

    <section title="RTP monitoring architecture">
      <t>The RTP monitoring architecture comprises the following two key
      functional components shown below:<list style="symbols">
          <t>Monitor</t>

          <t>Metric Block Structure</t>
        </list></t>

      <t>Monitor is a functional component defined in RFC3550 that acts as a
      source of information gathered for monitoring purposes. It may also
      collect statistics from multiple source, stores such information
      reported by RTCP XR or other RTCP extension appropriately as base metric
      or calculates composite metric. According to the definition of monitor
      in RFC3550, the end system that source RTP streams, an
      intermediate-system that forwards RTP packets to End-devices or a third
      party that does not participate RTP session (i.e., the third party
      monitor depicted in figure 1) can be envisioned to act as the Monitor
      within the RTP monitoring architecture.</t>

      <t>The Metric Block exposes real time Application Quality information in
      the appropriate report block format to the Monitor within the RTP
      monitoring architecture. Both the RTCP or RTCP XR can be extended to
      convey such information. The details on transport protocol for metric
      block is described in <xref target="sec2"></xref>.</t>

      <figure anchor="ARCH" title="RTP Monitoring Architecture">
        <artwork>
                                             |---------------+
                                             | Management    |
             +-------------------+           |   System      |
             | RTP Sender        |           |  +----------+ |
             |   +-----------+   |           |  |          | |
---------------->|  Monitor  |---------5------->|  Monitor | |
|            |   |           |   |           |  |          | |
|            |   +-----------+   |           |  +----\-----+ |
|            |+-----------------+|           |       |       |
|            ||Application      ||           --------|-------+
|            ||-Streaming video ||                   |
|   |---------|-VOIP            ||                   5
|   |        ||-Video conference||                   |
|   |        ||-Telepresence    ||       +---------------+
|   |        ||-Ad insertion    ||       |  Third Party  |
5   |        |+-----------------+|       |    Monitor    |
|   |        +-------------------+       +---------------+
|   1
|   | +Intermediate------------+         |-------------- ---- ----+
|   | | RTP System       Report Block    | RTP Receiver >--4-|    |
|   | |      +---------- transported over|    +-----------+  |    |
|   | |      |           RTCP extension  |    |  Monitor  |<--    |
|-------------  Monitor |<--------5------|----|           |<------|
    | |      |          |   Report Block      +----/------+      ||
    | |      +----------+   transported over       |             ||
    | |                     RTCP XR      |         |2            ||
    | | +-----------------+    |         | +-------/---------+   ||
    | | |Application      |    |         | |Application      |   ||
    | | |-Streaming video |    |         | |-Streaming video |   ||
    | | |-VOIP            |    |    1    | |-VOIP            |   3|
    ---->-Video conference|--------------->|-Video conference    ||
      | |-Telepresence    |    |         | |-Telepresence    |   ||
      | |-Ad insertion    |    |         | |-Ad insertion    |   ||
      | +-----------------+    |         | +-----------------+   ||
      | +-----------------+    |         | +-----------------+   ||
      | |Transport        |    |         | |Transport        |   ||
      | |-IP/UDP/RTP      |    |         | |-IP/UDP/RTP      >---||
      | |-IP/TCP/RTP      |    |         | | -IP/TCP/RTP     |    |
      | |-IP/TCP/RTSP/RTP |    |         | |-IP/TCP/RTSP/RTP |    |
      | +-----------------+    |         | +-----------------+    |
      +------------------------+         +------------------------+

</artwork>
      </figure>

      <t><list style="numbers">
          <t>RTP communication between real time applications.</t>

          <t>Application level metrics collection.</t>

          <t>Transport level metrics collection.</t>

          <t>End System metrics collection.</t>

          <t>Reporting Session- metrics transmitted over specified
          interfaces.</t>
        </list></t>

      <section anchor="sec2"
               title="RTCP Metric Block Report and associated parameters">
        <t>The basic RTCP Reception Report (RR) conveys reception statistics
        in metric block report format for multiple RTP media streams including
        <list style="symbols">
            <t>transport level statistics</t>

            <t>the fraction of packet lost since the last report</t>

            <t>the cumulative number of packets lost</t>

            <t>the highest sequence number received</t>

            <t>an estimate of the inter-arrival jitter</t>

            <t>and information to allow senders to calculate the network round
            trip time.</t>
          </list>The RTCP XRs <xref target="RFC3611"></xref> supplement the
        existing RTCP packets and provide more detailed feedback on reception
        quality in several categories:<list style="symbols">
            <t>Loss and duplicate RLE reports</t>

            <t>Packet-receipt times reports</t>

            <t>Round-trip time reports</t>

            <t>Statistics Summary Reports</t>
          </list></t>

        <t>There are also various other scenarios in which it is desirable to
        send RTCP Metric reports more frequently. The Audio/Video Profile with
        Feedback <xref target="RFC4585"></xref>extends the standard A/V
        Profile<xref target="RFC3551"></xref> to allow RTCP reports to be sent
        early provided RTCP bandwidth allocation is respected. There are four
        use cases but are not limited to:<list style="symbols">
            <t hangText="Retransmission">RTCP NACK is used to provide feedback
            on the RTP sequence number of the lost packets. <xref
            target="RFC4585"></xref></t>

            <t hangText="Rapid acquisition of multicast sessions">RTCP XR is
            extended to provide feedback on multicast acquisition statistics
            information and parameters.<xref target="RFC6332"></xref></t>

            <t hangText="Codec Control">RTCP is extended to convey requests
            for full intra-coded frames or select the reference picture, and
            signalchanges in the desired temporal/spatial trade-off and
            maximum media bit rate. <xref target="RFC5104"></xref></t>

            <t hangText="Congestion Notification">RTCP or RTCP XR is extended
            to provide feedback on ECN statistics information. <xref
            target="ECN"></xref></t>
          </list></t>
      </section>
    </section>

    <section title="Issues with reporting metric block using RTCP XR extension">
      <t>Issues that have come up in the past with reporting metric block
      using RTCP XR extensions include (but are probably not limited to) the
      following:<list style="symbols">
          <t>Using large block. A single report block or metric is designed to
          contain a large number of parameters in different classes for a
          specific application. For example, RFC 3611 <xref
          target="RFC3611"></xref> defines seven report block formats for
          network management and quality monitoring. However some of these
          block types defined in <xref target="RFC3611"></xref> are only
          specifically designed for conveying multicast inference of network
          characteristics(MINC) or voice over IP (VoIP) monitoring. However
          different applications layered on RTP may have some monitoring
          requirements in common, design large block only for specific
          applications may increase implementation cost and minimize
          interoperability.</t>

          <t>Correlating RTCP XR with the non-RTP data. CNAME <xref
          target="RFC3550"></xref> is an example of existing tool that allows
          to bind an SSRC that may change to a fixed source name in one RTP
          session. It is also fixed across multiple RTP sessions from the same
          source. However there may be situations where RTCP reports are sent
          to other participating endpoints using non-RTP protocol in a
          session. For example, as described in <xref
          target="RFC6035"></xref>, the data contained in RTCP XR VoIP metrics
          reports <xref target="RFC3611"></xref> are forwarded to a central
          collection server systems using SIP. In such case, there is a large
          portfolio of quality parameters that can be associated with real
          time application,e.g., VOIP application, but only a minimal number
          of parameters are included on the RTCP-XR reports. Therefore
          correlation between RTCP XR and non-RTP data should be concerned if
          administration or management systems need to rely on the mapping
          RTCP statistics to non-RTCP measurements to conducts data analysis
          and creates alerts to the users. Without such correlation, it is
          hardly to provide accurate measures of real time application quality
          with a minimal number of parameters included on the RTCP-XR reports
          in such case.</t>

          <t>Identity Information duplication. Identity information is used to
          identify an instance of a metric block. The SSRC of the measured
          stream as part of the metric block is one example of Identity
          information. However in some cases, Identity information may be not
          part of metric and include information more than the SSRC in the
          metric block, e.g., when we set a metric interval for the session
          and monitor RTP packets within one or several consecutive metric
          interval, extra identity information (e.g., sequence number of 1st
          packet) is expected, if we put such extra identity information into
          each metric block, there may be situations where an RTCP XR packet
          containing more than two metric blocks including the duplicated
          extra identity information, reports on the same streams from the
          same source. each block have the same extra identity information for
          measurement, if each metric block carry such duplicated data for the
          measurement, it leads to redundant information in this design since
          equivalent information is provided multiple times, once in *every*
          metric block. Though this ensures immunity to packet loss, the
          design may bring more complexity and the overhead is not completely
          trivial in some cases.</t>
        </list></t>
    </section>

    <section title=" Guideline for reporting block format using RTCP XR">
      <section anchor="smallblock" title="Using small blocks">
        <t>Different applications using RTP for media transport certainly have
        differing requirements for metrics transported in RTCP to support
        their operation. For many applications, the basic metrics for
        transport impairments provided in RTCP SR and RR packets <xref
        target="RFC3550"></xref> (together with source identification provided
        in RTCP SDES packets) are sufficient. For other applications
        additional metrics may be required or at least sufficiently useful to
        justify the overheads, both of processing in endpoints and of
        increased session bandwidth. For example an IPTV application using
        Forward Error Correction (FEC) might use either a metric of
        post-repair loss or a metric giving detailed information about
        pre-repair loss bursts to optimise payload bandwidth and the strength
        of FEC required for changing network conditions. However there are
        many metrics available. It is likely that different applications or
        classes of applications will wish to use different metrics. Any one
        application is likely to require metrics for more than one parameter
        but if this is the case, different applications will almost certainly
        require different combinations of metrics. If larger blocks are
        defined containing multiple metrics to address the needs of each
        application, it becomes likely that many different such larger blocks
        are defined, which becomes a danger to interoperability.</t>

        <t>To avoid this pitfall, this memo proposes the use of small RTCP XR
        metrics blocks each containing a very small number of individual
        metrics characterizing only one parameter of interest to an
        application running over RTP. For example, at the RTP transport layer,
        the parameter of interest might be packet delay variation, and
        specifically the metric "IPDV" defined by <xref
        target="Y1540"></xref>. See <xref target="example"></xref> for
        architectural considerations for a metrics block, using as an example
        a metrics block to report packet delay variation.</t>
      </section>

      <section title="Correlating identity information with the non-RTP data">
        <t>When more than one media transport protocols are used by one
        application to interconnected to the same session (in gateway),e.g.,
        one RTCP XR Packet is sent to the participating endpoints using non-
        RTP-based media transport (e.g., using SIP) in a VOIP session, one
        crucial factor lies in how to handle their different identities that
        are corresponding to different media transport.</t>

        <t>This memo proposes an approach to facilitate the correlation of the
        RTCP Session with other session-related non-RTP data, i.e., if there
        is a need to correlate RTP sessions with non-RTP sessions, then the
        correlation information needed should be conveyed in RTCP SDES packets
        since such correlation information describes the source, rather than
        providing a quality report. An example use case is for a participant
        endpoint may convey a call identifier or a global call identifier
        associated with the SSRC of measured RTP stream . In such case, the
        participant endpoint uses SSRC of source to bind the call identifier
        in each chunk of the SDES RTCP packet and send such correlation using
        the chunk containing SDES item to the network management system. A
        flow measurement tool that is not call-aware then forward the RTCP XR
        reports along with SSRC of the measured RTP stream which is included
        in the XR Block header to the network management system. Network
        management system can then correlate this report using SSRC with other
        diagnostic information such as call detail records. </t>
      </section>
    </section>

    <section anchor="example" title="An example of a metric block">
      <t>This section uses the example of an existing proposed metrics block
      to illustrate the application of the principles set out in <xref
      target="smallblock"></xref>.</t>

      <t>The example <xref target="PDV"></xref> (work in progress) is a block
      to convey information about packet delay variation (PDV) only,
      consistent with the principle that a metrics block should address only
      one parameter of interest. One simple metric of PDV is available in the
      RTCP RR packet as the "jit" field. There are other PDV metrics which may
      be more useful to certain applications. Two such metrics are the IPDV
      metric (<xref target="Y1540"></xref>, <xref target="RFC3393"></xref>)
      and the MAPDV2 metric <xref target="G1020"></xref>. Use of these metrics
      is consistent with the principle in Section 5 of <xref
      target="RFC5968"></xref> that metrics should usually be defined
      elsewhere, so that RTCP standards define only the transport of the
      metric rather than its nature. The purpose of this section is to
      illustrate the architecture using the example of <xref
      target="PDV"></xref> (work in progress) rather than to document the
      design of the PDV metrics block or to provide a tutorial on PDV in
      general.</t>

      <t>Given the availability of at least three metrics for PDV, there are
      design options for the allocation of metrics to RTCP XR blocks:</t>

      <t><list style="symbols">
          <t>provide an RTCP XR block per metric</t>

          <t>provide a single RTCP XR block which contains all three
          metrics</t>

          <t>provide a single RTCP block to convey any one of the three
          metrics, together with a identifier to inform the receiving RTP
          system of the specific metric being conveyed</t>
        </list></t>

      <t>In choosing between these options, extensibility is important,
      because additional metrics of PDV may well be standardized and require
      inclusion in this framework. The first option is extensible but only by
      use of additional RTCP XR blocks, which may consume the limited
      namespace for RTCP XR blocks at an unacceptable rate. The second option
      is not extensible, so could be rejected on that basis, but in any case a
      single application is quite unlikely to require transport of more than
      one metric for PDV. Hence the third option was chosen. This implies the
      creation of a subsidiary namespace to enumerate the PDV metrics which
      may be transported by this block, as discussed further in <xref
      target="PDV"></xref> (work in progress).</t>
    </section>

    <section anchor="topologies" title="Application to RFC 5117 topologies">
      <t>The topologies specified in <xref target="RFC5117"></xref> fall into
      two categories. The first category relates to the RTP system model
      utilizing multicast and/or unicast. The topologies in this category are
      specifically Topo-Point-to-Point, Topo- Multicast, Topo-Translator (both
      variants, Topo-Trn-Translator and Topo-Media-Translator, and
      combinations of the two), and Topo-Mixer. These topologies use RTP end
      systems, RTP mixers and RTP translators defined in <xref
      target="RFC3550"></xref>. For purposes of reporting connection quality
      to other RTP systems, RTP mixers and RTP end systems are very similar.
      Mixers resynchronize audio packets and do not relay RTCP reports
      received from one cloud towards other cloud(s). Translators do not
      resynchronize packets and SHOULD forward certain RTCP reports between
      clouds. In this category, the RTP system (end system, mixer or
      translator) which originates, terminates or forwards RTCP XR blocks is
      expected to handle RTCP, including RTCP XR, according to <xref
      target="RFC3550"></xref>. Provided this expectation is met, an RTP
      system using RTCP XR is architecturally no different from an RTP system
      of the same class (end system, mixer, or translator) which does not use
      RTCP XR. The second category relates to deployed system models used in
      many H.323 <xref target="H323"></xref> video conferences. The topologies
      in this category are Topo-Video-Switch-MCU and
      Topo-RTCP-terminating-MCU. Such topologies based on systems do not
      behave according to <xref target="RFC3550"></xref>.</t>

      <t>Considering the translator and MCU are two typical topologies in the
      two categories mentioned above, this document will take them as two
      typical examples to explain how RTCP XR report works in different
      RFC5117 topologies. </t>

      <section title="Applicability to MCU">
        <t>Topo-Video-Switch-MCU and Topo-RTCP-terminating-MCU, suffer from
        the difficulties described in [RFC5117]. These difficulties apply to
        systems sending, and expecting to receive, RTCP XR blocks as much as
        to systems using other RTCP packet types. For example, a participant
        RTP end system may send media to a video switch MCU. If the media
        stream is not selected for forwarding by the switch, neither RTCP RR
        packets nor RTCP XR blocks referring to the end system's generated
        stream will be received at the RTP end system. Strictly the RTP end
        system can only conclude that its RTP has been lost in the network,
        though an RTP end system complying with the robustness principle of
        [RFC1122] should survive with essential functions unimpaired.</t>
      </section>

      <section anchor="txlat" title="Applicability to Translators">
        <t>Section 7.2 of <xref target="RFC3550"></xref> describes processing
        of RTCP by translators. RTCP XR is within the scope of the
        recommendations of <xref target="RFC3550"></xref>. Some RTCP XR
        metrics blocks may usefully be measured at, and reported by,
        translators. As described in <xref target="RFC3550"></xref> this
        creates a requirement for the translator to allocate an SSRC for the
        monitor collocated with itself so that the monitor may populate the
        SSRC in the RTCP XR packet header as packet sender SSRC and send it
        out(although the translator is not a Synchronisation Source in the
        sense of originating RTP media packets). It must also supply this SSRC
        and the corresponding CNAME in RTCP SDES packets. </t>

        <t>In RTP sessions where one or more translators generate any RTCP
        traffic towards their next-neighbour RTP system, other translators in
        the session have a choice as to whether they forward a translator's
        RTCP packets. Forwarding may provide additional information to other
        RTP systems in the connection but increases RTCP bandwidth and may in
        some cases present a security risk. RTP translators may have
        forwarding behaviour based on local policy, which might differ between
        different interfaces of the same translator.</t>

        <t>For bidirectional unicast, an RTP system may usually detect RTCP XR
        from a translator by noting that the sending SSRC is not present in
        any RTP media packet. However there is a possibility of a source
        sending RTCP XR before it has sent any RTP media (leading to transient
        mis-categorisation of an RTP end system or RTP mixer as a translator),
        and for multicast sessions - or unidirectional/streaming unicast -
        there is also a possibility of a receive-only end system being
        permanently mis-categorised as a translator sending XR report,
        i.e.,the monitor sending XR report within the translator. Hence it is
        desirable for a translator that sends XR report to have a way to
        declare itself explicitly. </t>
      </section>
    </section>

    <section title="IANA Considerations">
      <t>None.</t>
    </section>

    <section title="Security Considerations">
      <t>This document itself contains no normative text and hence should not
      give rise to any new security considerations, to be confirmed.</t>
    </section>

    <section title="Acknowledgement">
      <t>The authors would also like to thank Colin Perkins, Graeme Gibbs,
      Debbie Greenstreet, Keith Drage, Dan Romascanu, Ali C. Begen, Roni Even
      for their valuable comments and suggestions on the early version of this
      document.</t>
    </section>
  </middle>

  <back>
    <references title="Informative References">
      <reference anchor="RFC1122">
        <front>
          <title>Requirements for Internet Hosts -- Communication
          Layers</title>

          <author initials="R." surname="Braden">
            <organization>USC/ISI</organization>
          </author>

          <date month="October" year="1989" />
        </front>

        <seriesInfo name="RFC" value="1122" />

        <format type="TXT" />
      </reference>

      <reference anchor="RFC3393">
        <front>
          <title>IP Packet Delay Variation Metric for IP Performance Metrics
          (IPPM)</title>

          <author fullname="Carlo Demichelis" initials="C."
                  surname="Demichelis">
            <organization>Telecomitalia Lab</organization>
          </author>

          <date month="November" year="2002" />
        </front>

        <seriesInfo name="RFC" value="3393" />

        <format type="TXT" />
      </reference>

      <reference anchor="RFC3550">
        <front>
          <title>RTP: A Transport Protocol for Real-Time Applications</title>

          <author fullname="Henning Schulzrinne" initials="H."
                  surname="Schulzrinne">
            <organization>Columbia University</organization>
          </author>

          <date month="July" year="2003" />
        </front>

        <seriesInfo name="RFC" value="3550" />

        <format type="TXT" />
      </reference>

      <reference anchor="RFC3611">
        <front>
          <title>RTP Control Protocol Extended Reports (RTCP XR)</title>

          <author fullname="Timur Friedman" initials="T. (Ed)"
                  surname="Friedman">
            <organization>Paris 6</organization>
          </author>

          <date month="November" year="2003" />
        </front>

        <seriesInfo name="RFC" value="3611" />

        <format type="TXT" />
      </reference>

      <reference anchor="RFC5117">
        <front>
          <title>RTP Topologies</title>

          <author fullname="Magnus Westerlund" initials="M."
                  surname="Westerlund">
            <organization>Ericsson Research</organization>
          </author>

          <date month="January" year="2008" />
        </front>

        <seriesInfo name="RFC" value="5117" />

        <format type="TXT" />
      </reference>

      <reference anchor="RFC5968">
        <front>
          <title>Guidelines for Extending the RTP Control Protocol
          (RTCP)</title>

          <author fullname="Joerg Ott" initials="J." surname="Ott">
            <organization>Helsinki University of Technology</organization>
          </author>

          <author fullname="C. Perkins" initials="C." surname="Perkins">
            <organization>University of Glasgow</organization>
          </author>

          <date month="September" year="2010" />
        </front>

        <seriesInfo name="RFC" value="5968" />

        <format type="TXT" />
      </reference>

      <reference anchor="RFC4585">
        <front>
          <title>Extended RTP Profile for Real-time Transport Control Protocol
          (RTCP)-Based Feedback (RTP/AVPF)</title>

          <author fullname="Joerg Ott" initials="J." surname="Ott">
            <organization>Helsinki University of Technology</organization>
          </author>

          <author fullname="S. Wenger" initials="S." surname="Wenger">
            <organization>Nokia</organization>
          </author>

          <date month="July" year="2006" />
        </front>

        <seriesInfo name="RFC" value="4585" />

        <format type="TXT" />
      </reference>

      <reference anchor="RFC3551">
        <front>
          <title>Extended RTP Profile for Real-time Transport Control Protocol
          (RTCP)-Based Feedback (RTP/AVPF)</title>

          <author fullname="H. Schulzrinne" initials="H."
                  surname="Schulzrinne ">
            <organization>Columbia University</organization>
          </author>

          <author fullname="S. Casner" initials="S." surname="Casner">
            <organization>Packet Design</organization>
          </author>

          <date month="July" year="2003" />
        </front>

        <seriesInfo name="RFC" value="3551" />

        <format type="TXT" />
      </reference>

      <reference anchor="RFC6035">
        <front>
          <title>Session Initiation Protocol Event Package for Voice Quality
          Reporting</title>

          <author fullname="A. Pendleton" initials="A." surname="Pendleton">
            <organization>Telchemy Incorporated</organization>
          </author>

          <author fullname="A. Clark" initials="A." surname="Clark">
            <organization>Telchemy Incorporated</organization>
          </author>

          <author fullname="A. Johnston" initials="A." surname="Johnston">
            <organization>Avaya</organization>
          </author>

          <author fullname="H. Sinnreich" initials="H." surname="Sinnreich">
            <organization>Unaffiliated</organization>
          </author>

          <date month="November" year="2010" />
        </front>

        <seriesInfo name="RFC" value="6035" />

        <format type="TXT" />
      </reference>

      <reference anchor="RFC5104">
        <front>
          <title>Session Initiation Protocol Event Package for Voice Quality
          Reporting</title>

          <author fullname="Stephan Wenger" initials="S." surname="Wenger">
            <organization></organization>
          </author>

          <author fullname="Umesh Chandra" initials="U." surname="Chandra">
            <organization></organization>
          </author>

          <author fullname="Magnus Westerlund" initials="M."
                  surname="Westerlund">
            <organization></organization>
          </author>

          <author fullname="Bo Burman" initials="B." surname="Burman">
            <organization>Unaffiliated</organization>
          </author>

          <date month="February" year="2008" />
        </front>

        <seriesInfo name="RFC" value="5104" />

        <format type="TXT" />
      </reference>

      <reference anchor="RFC6332">
        <front>
          <title>Multicast Acquisition Report Block Type for RTP Control
          Protocol (RTCP) Extended Reports (XRs) </title>

          <author fullname="Ali Begen" initials="A." surname="Begen">
            <organization></organization>
          </author>

          <author fullname="Eric Friedrich" initials="E." surname="Friedrich">
            <organization></organization>
          </author>

          <date month="July" year="2011" />
        </front>

        <seriesInfo name="RFC" value="6332" />

        <format type="TXT" />
      </reference>

      <reference anchor="PDV">
        <front>
          <title>RTCP XR Report Block for Packet Delay Variation Metric
          Reporting</title>

          <author fullname="Geoff Hunt" initials="G." surname="Hunt">
            <organization>BT</organization>
          </author>

          <date month="May" year="2009" />
        </front>

        <seriesInfo name="ID" value="draft-ietf-avt-rtcp-xr-pdv-03" />

        <format type="TXT" />
      </reference>

      <reference anchor="MQ">
        <front>
          <title>RTCP XR Blocks for multimedia quality metric
          reporting</title>

          <author fullname="Qin Wu" initials="Q." surname="Wu">
            <organization></organization>
          </author>

          <author fullname="Glen Zorn" initials="G." surname="Zorn">
            <organization></organization>
          </author>

          <author fullname="Roland Schott" initials="R." surname="Schott">
            <organization></organization>
          </author>

          <author fullname="Kai Lee" initials="K." surname="Lee">
            <organization></organization>
          </author>

          <date month="May" year="2011" />
        </front>

        <seriesInfo name="ID"
                    value="draft-wu-xrblock-rtcp-xr-quality-monitoring-02" />

        <format type="TXT" />
      </reference>

      <reference anchor="G1020">
        <front>
          <title>ITU-T Rec. G.1020, Performance parameter definitions for
          quality of speech and other voiceband applications utilizing IP
          networks</title>

          <author>
            <organization>ITU-T</organization>
          </author>

          <date month="July" year="2006" />
        </front>

        <format type="TXT" />
      </reference>

      <reference anchor="Y1540">
        <front>
          <title>ITU-T Rec. Y.1540, IP packet transfer and availability
          performance parameters</title>

          <author fullname="" initials="" surname="">
            <organization>ITU-T</organization>
          </author>

          <date month="November" year="2007" />
        </front>

        <format type="TXT" />
      </reference>

      <reference anchor="H323">
        <front>
          <title>ITU-T Rec. H.323, Packet-based multimedia communications
          systems</title>

          <author fullname="" initials="" surname="">
            <organization>ITU-T</organization>
          </author>

          <date month="June" year="2006" />
        </front>

        <format type="TXT" />
      </reference>

      <reference anchor="ECN">
        <front>
          <title>Explicit Congestion Notification (ECN) for RTP over
          UDP</title>

          <author fullname="Magnus Westerlund" initials="M."
                  surname="Westerlund">
            <organization>Ericsson</organization>
          </author>

          <author fullname="Ingemar Johansson" initials="I."
                  surname="Johansson">
            <organization>Ericsson</organization>
          </author>

          <author fullname="Colin Perkins" initials="C." surname="Perkins">
            <organization></organization>
          </author>

          <author fullname="Piers O'Hanlon" initials="P." surname="O'Hanlon">
            <organization></organization>
          </author>

          <author fullname="Ken Carlberg" initials="K." surname="Carlberg">
            <organization></organization>
          </author>

          <date month="July" year="2011" />
        </front>

        <seriesInfo name="ID" value="draft-ietf-avtcore-ecn-for-rtp-04" />

        <format type="TXT" />
      </reference>
    </references>

    <section title="Change Log">
      <t>Note to the RFC-Editor: please remove this section prior to
      publication as an RFC.</t>

      <section title="draft-ietf-avtcore-monarch-00">
        <t>The following are the major changes compared to
        draft-hunt-avtcore-monarch-02: <list style="symbols">
            <t>Move Geoff Hunt and Philip Arden to acknowledgement
            section.</t>
          </list></t>
      </section>

      <section title="draft-ietf-avtcore-monarch-01">
        <t>The following are the major changes compared to 00: <list
            style="symbols">
            <t>Restructure the document by merging section 4 into section
            3.</t>

            <t>Remove section 4.1,section 5 that is out of scope of this
            document.</t>

            <t>Remove the last bullet in section 6 and section 7.3 based on
            conclusion of last meeting.</t>

            <t>Update figure 1 and related text in section 3 according to the
            monitor definition in RFC3550.</t>

            <t>Revise section 9 to address monitor declaration issue.</t>

            <t>Merge the first two bullet in section 6.</t>

            <t>Add one new bullet to discuss metric block association in
            section 6.</t>
          </list></t>
      </section>

      <section title="draft-ietf-avtcore-monarch-02">
        <t>The following are the major changes compared to 01: <list
            style="symbols">
            <t>Deleting first paragraph of Section 1.</t>

            <t>Deleting Section 3.1, since the interaction with the management
            application is out of scope of this draft.</t>

            <t>Separeate identity information correlation from section 5.2 as
            new section 5.3.</t>

            <t>Remove figure 2 and related text from section 5.2.</t>

            <t>Editorial changes in the section 4 and the first paragraph of
            section 7.</t>
          </list></t>
      </section>

      <section title="draft-ietf-avtcore-monarch-03">
        <t>The following are the major changes compared to 02: <list
            style="symbols">
            <t>Update bullet 2 in section 4 to explain the ill-effect of
            Identity Information duplication.</t>

            <t>Update bullet 3 in section 4 to explain why Correlating RTCP XR
            with the non-RTP data is needed.</t>

            <t>Update section 5.2 to focus on how to reduce the identity
            information repetition</t>

            <t>Update section 5.3 to explain how to correlate identity
            information with the non-RTP data</t>
          </list></t>
      </section>

      <section title="draft-ietf-avtcore-monarch-04">
        <t>The following are the major changes compared to 03: <list
            style="symbols">
            <t>Update section 5.2 to clarify using SDES packet to carry
            correlation information.</t>

            <t>Remove section 5.3 since additional identity information goes
            to SDES packet and using SSRC to identify each block is standard
            RTP feature.</t>

            <t>Swap the last two paragraphs in the section 4 since identity
            information duplication can not been 100% avoided.</t>

            <t>Other editorial changes.</t>
          </list></t>
      </section>
    </section>
  </back>
</rfc>

PAFTECH AB 2003-20262026-04-23 15:33:55