One document matched: draft-ietf-avt-rtcp-xr-meas-identity-02.xml

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<rfc category="std" ipr="trust200811" docName="draft-ietf-avt-rtcp-xr-meas-identity-02.txt">

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    <front>
        <title abbrev='RTCP XR Measurement Identity'>RTCP XR Report Block for Measurement Identity</title>
        <author initials='G.' surname='Hunt' fullname='Geoff Hunt'>
            <organization abbrev='BT'>BT</organization>
		<address>
	    <postal>
        	<street>Orion 2 PP3</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 651704</phone>
	    <email>geoff.hunt@bt.com</email>
	    </address>
        </author>
        <author initials='A.' surname='Clark' fullname='Alan Clark'>
            <organization abbrev='Telchemy'>Telchemy Incorporated</organization>
		<address>
	    <postal>
        	<street>2905 Premiere Parkway, Suite 280</street>
        	<city>Duluth</city> <region>GA</region>
        	<code>30097</code>
        	<country>USA</country>
    	    </postal>
	    <email>alan.d.clark@telchemy.com</email>
	    </address>
        </author>
        <date month='May' year='2009' />
       <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 document defines an RTCP XR Report Block carrying parameters which identify a
measurement, to which one or more other RTCP XR Report Blocks may refer.
        </t>
        </abstract>
    </front>

    <middle>

<section anchor='intro' title="Introduction">
<section anchor='intro1' title="Measurement Identity Report Block">
<t>
   This draft defines a new block type to augment those defined
   in <xref target='RFC3611'/> for use in a range of RTP applications.
   This block type does not itself contain any measurement results
   (metrics). However, this new block type
   provides information relevant to a measurement reported in one or more
   other block types, including
</t>
<t>
<list style='symbols'>
<t>
a tag or key by which other blocks (containing metrics information) may
refer to this block
</t><t>
the SSRC of the measured stream, 
</t><t>
a field for incorporation of an application-specific auxiliary identifier,
</t>
<t>
   the sequence number of the first packet of the RTP session,
</t>
<t>
   the extended sequence numbers of the first packet of the current
measurement interval, and the last packet included in the
   measurement,
</t>
<t>
the duration of the most recent measurement interval and 
</t><t>
   the duration of the interval applicable to cumulative measurements
   (which may be the duration of the RTP session to date).
</t>
</list>
</t>
<t>
The method for calculation of the extended RTP sequence number is provide in <xref target='RFC3550'/>.
</t><t>
This block is intended to provide a single copy of the information necessary to relate measurement data in other blocks to the 
stream, and measurement period, to which they refer. Commonly, multiple other small blocks contain measurement data for the 
same stream and period, and it would be a large overhead if all of these blocks carried duplicated data for measurement 
identification. Other blocks make a reference to this block (by tag).
</t><t>
A Measurement Identity block is associated with the set of RTCP XR metrics blocks which share its tag value. There MAY be several 
such sets in an RTCP packet, up to a limit of 8 arising from the use of 3-bit tags. There MAY also be RTCP XR blocks in the packet
which are not associated with a Measurement Identity block, for example blocks which were defined before the Measurement Identity 
mechanism was introduced by this document.
</t>
</section>
<section anchor='intro2' title="RTCP and RTCP XR Reports">
<t>
   The use of RTCP for reporting is defined in <xref target='RFC3550'/>. 
   <xref target='RFC3611'/> defined an extensible structure for reporting using
   an RTCP Extended Report (XR).  This draft defines
   a new Extended Report block that MUST be used as defined in
   <xref target='RFC3550'/> and <xref target='RFC3611'/>.
</t>
</section>
<section anchor='intro3' title="Performance Metrics Framework">
<t>
   The Performance Metrics Framework <xref target='PMOLFRAME'/> provides guidance on the
   definition and specification of performance metrics.  Metrics
   described in this draft either reference external definitions
   or define metrics generally in accordance with the guidelines
   in <xref target='PMOLFRAME'/>.
</t>
</section>
<section anchor='intro4' title="Applicability">
<t>
This block provides identification information for members of a family of
RTCP XR metrics blocks which are designed to use it.
To use the mechanism defined here, a metrics block must be in the same
RTCP packet as the Measurement Identity block and must refer to the
Measurement Identity block via the 3-bit tag field
defined below.
</t>
</section>
</section>

<section anchor='blockdef' title="Measurement Identity Block">
<section anchor='blockdef1' title="Report Block Structure">
    <figure anchor='blockdata' title="Report Block Structure">
        <artwork>
       0               1               2               3
       0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     BT=NMI    |0| tag | resv  |      block length = 7         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                    SSRC of stream source                      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        sub-identifier                         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |            reserved           |         first seq num         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |           extended first sequence number of interval          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                 extended last sequence number                 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |          Measurement Duration (Cumulative) (ms)               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |           Measurement Duration (Interval) (ms)                |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        </artwork>
    </figure>
</section>
<section anchor='blockdef2' title="Definition of Fields in Measurement Identity Report Block">
<t>
Bits shown as '0' in the figure SHOULD be set to zero.
</t>
<t>
   block type (BT): 8 bits
</t>
<t>
<list style='empty'>
<t>
         A Measurement Identity Report Block is identified by the constant 
         NMI. 
</t>
</list>
</t>
<t>
[Note to RFC Editor: please replace NMI with the
         IANA provided RTCP XR block type for this block.]
</t>
<t>
   tag: 3 bits
</t>
<t>
<list style='empty'>
<t>
This field is a tag or key which identifies this Measurement Identity block
within the scope of an RTCP packet.
If an RTCP packet contains more than one Measurement Identity block, each
Measurement Identity block MUST have a unique
tag field to enable metrics blocks in the same RTCP packet to refer
unambiguously to the correct Measurement Identity block. The 3-bit field
allows up to 8 Measurement Identity blocks in each RTCP packet. If
additional metrics must be sent at a given time, and they require more
than 8 blocks of Measurement Identity information, then the metrics must be sent
in multiple RTCP packets.
</t>
</list>
</t>
<t>
   resv: 4 bits
</t>
<t>
<list style='empty'>
<t>
These bits are reserved. They MUST be set to zero by senders. They MUST be ignored by receivers.
</t>
</list>
</t>
<t>
   block length: 16 bits
</t>
<t>
<list style='empty'>
<t>
The length of this report block in 32-bit words minus one. For the
Measurement Identity block, the block length
is equal to 7.
</t>
</list>
</t>
<t>
   SSRC of source: 32 bits
</t>
<t>
<list style='empty'>
<t>
The SSRC <xref target='RFC3550'/> of the source of the stream being reported. Note that the SSRC of the reporting 
RTP system (the originator of the report block) is present in the RTCP XR header defined in Section 2 of <xref target='RFC3611'/>.
</t>
</list>
</t>
<t>
   sub-identifier: 32 bits
</t>
<t>
<list style='empty'>
<t>
An additional identifier which is useful in the context of a specific application,
e.g. an MPEG-2 transport identifier <xref target='MPEG2'/>.
Where the identifier is less than 32 bits, the identifier SHOULD be mapped into the most significant bits of the field. If no additional
identifier is provided, all bits of the field MUST be set to zero. This field MUST be ignored by applications which 
are not configured to make use of it.
</t>
</list>
</t>
<t>
reserved: 16 bits
</t>
<t>
<list style='empty'>
<t>
These bits are reserved. They MUST be ignored by receivers. They MUST be set to zero by senders.
</t>
</list>
</t>
<t>
first seq num: 16 bits
</t>
<t>
<list style='empty'>
<t>
The RTP sequence number of the first received RTP packet of the session, used to determine the number of 
packets contributing to cumulative measurements.
</t>
</list>
</t>
<t>
extended first sequence number of interval: 32 bits
</t>
<t>
<list style='empty'>
<t>
The extended RTP sequence number of the first received RTP packet of the current measurement interval.
</t>
</list>
</t>
<t>
extended last sequence number: 32 bits
</t>
<t>
<list style='empty'>
<t>
The extended RTP sequence number of the last received RTP packet which contributed to this measurement.
</t>
</list>
</t>
<t>
Measurement Duration (Cumulative) (ms): 32 bits
</t>
<t>
<list style='empty'>
<t>
The duration in ms of the reporting interval applicable to Cumulative reports which use this 
Measurement Identity block.
</t>
</list>
</t>
<t>
Measurement Duration (Interval) (ms): 32 bits
</t>
<t>
<list style='empty'>
<t>
The duration in ms of the reporting interval applicable to Interval reports which use this 
Measurement Identity block.
</t>
</list>
</t>
</section>
</section>

<section anchor='sdp' title="SDP Signaling">
<t>
   <xref target='RFC3611'/> defines the use of SDP (Session Description Protocol) 
   <xref target='RFC4566'/> for signaling the use of XR blocks.  XR blocks MAY be used without
   prior signaling.
</t>
<t>
No additional SDP signaling is defined for this block. Instead, the need for this block SHOULD be inferred from a 
request in SDP signalling for a block type (such as <xref target='DISCARD'/>) which depends on it. 
</t>
</section>

<section title="IANA Considerations">
<t>
   New block types for RTCP XR are subject to IANA registration.  For
   general guidelines on IANA considerations for RTCP XR, refer to
   [RFC3611].
</t>
<section title="New RTCP XR Block Type value">
<t>   
   This document assigns the block type value NMI in the IANA "RTCP XR Block
   Type Registry" to the "Measurement Identity Block".
</t>
<t>
[Note to RFC Editor: please replace NMI with the
         IANA provided RTCP XR block type for this block.]
</t>
</section>
<section title="Contact information for registration">
<t>
   The contact information for the registration is:
</t>
<t>
   Geoff Hunt (geoff.hunt@bt.com)
</t>
<t>
   Orion 2 PP3, Adastral Park, Martlesham Heath, Ipswich IP5 3RE, United Kingdom
</t>
</section>
</section>

<section title="Security Considerations">
<t>
   RTCP reports can contain sensitive information since they can provide   
   information about the nature and duration of a session established   
   between two or more endpoints. 
</t>
</section>
<section title="Changes since last version">
<t>
Updated references.
</t>
</section>
</middle>

    <back>
<references title='Normative References'>
                <reference anchor='RFC3550'>
			<front> 
				<title>RTP: A Transport Protocol for Real-Time Applications</title> 
				<author initials='H.' surname='Schulzrinne' fullname='Henning 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 initials='T. (Ed)' surname='Friedman' fullname='Timur Friedman'> 
					<organization> Paris 6 </organization> 
				</author> 
				<date month='November' year='2003' /> 
			</front> 
			<seriesInfo name='RFC' value='3611' /> 	
			<format type='TXT' /> 
		</reference>
                <reference anchor='RFC2119'>
			<front> 
				<title>Key words for use in RFCs to Indicate Requirement Levels</title> 
				<author initials='S.' surname='Bradner' fullname='Scott Bradner'> 
					<organization>Harvard University</organization> 
				</author> 
				<date month='March' year='1997' /> 
			</front> 
			<seriesInfo name='RFC' value='2119' /> 	
			<seriesInfo name='BCP' value='14' /> 	
			<format type='TXT' /> 
		</reference>
                <reference anchor='RFC4566'>
			<front> 
				<title>SDP: Session Description Protocol</title> 
				<author initials='M.' surname='Handley' fullname='Mark Handley'> 
					<organization>UCL</organization> 
				</author> 
				<date month='July' year='2006' /> 
			</front> 
			<seriesInfo name='RFC' value='4566'/>
			<format type='TXT' /> 
		</reference>
</references>
        <references title='Informative References'>
		<reference anchor='PMOLFRAME'>
			<front>
                                <title>Framework for Performance Metric Development</title> 
                                <author initials='A.' surname='Clark' fullname='Alan Clark'> 
                                        <organization>Telchemy Incorporated</organization> 
				</author> 
                                <date month='March' year='2009' /> 
			</front> 
                        <seriesInfo name='ID' value='draft-ietf-pmol-metrics-framework-02' />  
			<format type='TXT' /> 
            </reference>
                <reference anchor='MONARCH'>
			<front> 
				<title>Monitoring Architectures for RTP</title> 
				<author initials='G.' surname='Hunt' fullname='Geoff Hunt'> 
					<organization>BT</organization> 
				</author> 
				<date month='August' year='2008' /> 
			</front> 
			<seriesInfo name='ID' value='draft-hunt-avt-monarch-01' /> 	
			<format type='TXT' /> 
		</reference>
                <reference anchor='DISCARD'>
			<front> 
                                <title>RTCP XR Report Block for Discard metric Reporting</title> 
				<author initials='G.' surname='Hunt' fullname='Geoff Hunt'> 
					<organization>BT</organization> 
				</author> 
                                <date month='May' year='2009' /> 
			</front> 
                        <seriesInfo name='ID' value='draft-ietf-avt-rtcp-xr-discard-02' />  
			<format type='TXT' /> 
		</reference>
                <reference anchor='MPEG2'>
			<front> 
                                <title>Standard 13818-1</title> 
                                <author initials='' surname='' fullname='ISO/IEC JTC1'> 
                                        <organization>ISO/IEC</organization>
                                        </author>
                                <date month='December' year='2000' /> 
			</front> 
			<format type='TXT' /> 
		</reference>
	</references>
    </back>

</rfc>