draft-ietf-avt-rtcp-xr-meas-identity-00.txt   draft-ietf-avt-rtcp-xr-meas-identity-01.txt 
Audio/Video Transport Working G. Hunt Audio/Video Transport Working G. Hunt
Group BT Group BT
Internet-Draft A. Clark Internet-Draft A. Clark
Intended status: Standards Track Telchemy Intended status: Standards Track Telchemy
Expires: April 28, 2009 October 25, 2008 Expires: August 29, 2009 February 25, 2009
RTCP XR Report Block for Measurement Identity RTCP XR Report Block for Measurement Identity
draft-ietf-avt-rtcp-xr-meas-identity-00.txt draft-ietf-avt-rtcp-xr-meas-identity-01.txt
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Abstract Abstract
This document defines an RTCP XR Report Block carrying parameters This document defines an RTCP XR Report Block carrying parameters
which identify a measurement, to which one or more other RTCP XR which identify a measurement, to which one or more other RTCP XR
Report Blocks may refer. Report Blocks may refer.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Measurement Identity Report Block . . . . . . . . . . . . 3 1.1. Measurement Identity Report Block . . . . . . . . . . . . 3
1.2. RTCP and RTCP XR Reports . . . . . . . . . . . . . . . . . 4 1.2. RTCP and RTCP XR Reports . . . . . . . . . . . . . . . . . 4
1.3. Performance Metrics Framework . . . . . . . . . . . . . . 4 1.3. Performance Metrics Framework . . . . . . . . . . . . . . 4
1.4. Applicability . . . . . . . . . . . . . . . . . . . . . . 4 1.4. Applicability . . . . . . . . . . . . . . . . . . . . . . 4
2. Measurement Identity Block . . . . . . . . . . . . . . . . . . 5 2. Measurement Identity Block . . . . . . . . . . . . . . . . . . 5
2.1. Report Block Structure . . . . . . . . . . . . . . . . . . 5 2.1. Report Block Structure . . . . . . . . . . . . . . . . . . 5
2.2. Definition of Fields in Measurement Identity Report 2.2. Definition of Fields in Measurement Identity Report
Block . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Block . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 8 3. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 8
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
4.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 9
4.2. Contact information for registration . . . . . . . . . . . 9
5. Security Considerations . . . . . . . . . . . . . . . . . . . 10 5. Security Considerations . . . . . . . . . . . . . . . . . . . 10
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 6. Changes since last version . . . . . . . . . . . . . . . . . . 11
6.1. Normative References . . . . . . . . . . . . . . . . . . . 11 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
6.2. Informative References . . . . . . . . . . . . . . . . . . 11 7.1. Normative References . . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12 7.2. Informative References . . . . . . . . . . . . . . . . . . 12
Intellectual Property and Copyright Statements . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction 1. Introduction
1.1. Measurement Identity Report Block 1.1. Measurement Identity Report Block
This draft defines a new block type to augment those defined in This draft defines a new block type to augment those defined in
[RFC3611] for use in a range of RTP applications. This block type [RFC3611] for use in a range of RTP applications. This block type
does not itself contain any measurement results (metrics). However, does not itself contain any measurement results (metrics). However,
this new block type provides information relevant to a measurement this new block type provides information relevant to a measurement
reported in one or more other block types, including reported in one or more other block types, including
o a tag or key by which other blocks (containing metrics o a tag or key by which other blocks (containing metrics
information) may refer to this block information) may refer to this block
o the SSRC of the measured stream, o the SSRC of the measured stream,
o a field for incorporation of an application-specific auxiliary o a field for incorporation of an application-specific auxiliary
identifier, identifier,
o the extended sequence numbers of the first packet of the RTP o the sequence number of the first packet of the RTP session,
session, the first packet of the current measurement interval, and
the last packet included in the measurement, o the extended sequence numbers of the first packet of the current
measurement interval, and the last packet included in the
measurement,
o the duration of the most recent measurement interval and o the duration of the most recent measurement interval and
o the duration of the interval applicable to cumulative measurements o the duration of the interval applicable to cumulative measurements
(which may be the duration of the RTP session to date). (which may be the duration of the RTP session to date).
The method for calculation of the extended RTP sequence number is The method for calculation of the extended RTP sequence number is
provide in [RFC3550]. provide in [RFC3550].
This block is intended to provide a single copy of the information This block is intended to provide a single copy of the information
skipping to change at page 5, line 12 skipping to change at page 5, line 12
RTCP packet as the Measurement Identity block and must refer to the RTCP packet as the Measurement Identity block and must refer to the
Measurement Identity block via the 3-bit tag field defined below. Measurement Identity block via the 3-bit tag field defined below.
2. Measurement Identity Block 2. Measurement Identity Block
2.1. Report Block Structure 2.1. Report Block Structure
0 1 2 3 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 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 | fwd | block length = 7 | | BT=NMI |0| tag | resv | block length = 7 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of stream source | | SSRC of stream source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sub-identifier | | sub-identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| extended first sequence number (cumulative) | | reserved | first seq num |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| extended first sequence number of interval | | extended first sequence number of interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| extended last sequence number | | extended last sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Measurement Duration (Cumulative) (ms) | | Measurement Duration (Cumulative) (ms) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Measurement Duration (Interval) (ms) | | Measurement Duration (Interval) (ms) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 6, line 7 skipping to change at page 6, line 7
Identity block within the scope of an RTCP packet. If an RTCP Identity block within the scope of an RTCP packet. If an RTCP
packet contains more than one Measurement Identity block, each packet contains more than one Measurement Identity block, each
Measurement Identity block MUST have a unique tag field to enable Measurement Identity block MUST have a unique tag field to enable
metrics blocks in the same RTCP packet to refer unambiguously to metrics blocks in the same RTCP packet to refer unambiguously to
the correct Measurement Identity block. The 3-bit field allows up the correct Measurement Identity block. The 3-bit field allows up
to 8 Measurement Identity blocks in each RTCP packet. If to 8 Measurement Identity blocks in each RTCP packet. If
additional metrics must be sent at a given time, and they require additional metrics must be sent at a given time, and they require
more than 8 blocks of Measurement Identity information, then the more than 8 blocks of Measurement Identity information, then the
metrics must be sent in multiple RTCP packets. metrics must be sent in multiple RTCP packets.
Forwarding count (fwd): 4 bits resv: 4 bits
These bits provide a count of the number of times the block, and These bits are reserved. They MUST be set to zero by senders.
those blocks which refer to it have been forwarded. They MUST be They MUST be ignored by receivers.
set to zero by the RTP system which creates the Measurement
Identity block. The Forwarding count SHOULD be incremented by any
RTP system which forwards the block, provided that the operation
does not cause the Forwarding count to wrap from 0xF to 0x0.
Then, values of the Forwarding count less than 0xF are
unambiguous. An RTP system which receives a block with Forwarding
count set to 0xF may deduce that the block has been forwarded 15
or more times.
block length: 16 bits block length: 16 bits
The length of this report block in 32-bit words minus one. For The length of this report block in 32-bit words minus one. For
the Measurement Identity block, the block length is equal to 5. the Measurement Identity block, the block length is equal to 7.
SSRC of source: 32 bits SSRC of source: 32 bits
The SSRC [RFC3550] of the source of the stream being reported. The SSRC [RFC3550] of the source of the stream being reported.
Note that the SSRC of the reporting RTP system (the originator of Note that the SSRC of the reporting RTP system (the originator of
the report block) is present in the RTCP XR header defined in the report block) is present in the RTCP XR header defined in
Section 2 of [RFC3611]. Section 2 of [RFC3611].
sub-identifier: 32 bits sub-identifier: 32 bits
An additional identifier which is useful in the context of a An additional identifier which is useful in the context of a
specific application, e.g. an MPEG-2 transport identifier [MPEG2]. specific application, e.g. an MPEG-2 transport identifier [MPEG2].
Where the identifier is less than 32 bits, the identifier SHOULD Where the identifier is less than 32 bits, the identifier SHOULD
be mapped into the most significant bits of the field. If no be mapped into the most significant bits of the field. If no
additional identifier is provided, all bits of the field MUST be additional identifier is provided, all bits of the field MUST be
set to zero. This field MUST be ignored by applications which are set to zero. This field MUST be ignored by applications which are
not configured to make use of it. not configured to make use of it.
extended first sequence number (cumulative): 32 bits reserved: 16 bits
The extended RTP sequence number of the first received RTP packet These bits are reserved. They MUST be ignored by receivers. They
relevant to cumulative measurements. Usually this will be the MUST be set to zero by senders.
extended sequence number of the first packet of the RTP session.
first seq num: 16 bits
The RTP sequence number of the first received RTP packet of the
session, used to determine the number of packets contributing to
cumulative measurements.
extended first sequence number of interval: 32 bits extended first sequence number of interval: 32 bits
The extended RTP sequence number of the first received RTP packet The extended RTP sequence number of the first received RTP packet
of the current measurement interval. of the current measurement interval.
extended last sequence number: 32 bits extended last sequence number: 32 bits
The extended RTP sequence number of the last received RTP packet The extended RTP sequence number of the last received RTP packet
which contributed to this measurement. which contributed to this measurement.
Measurement Duration (Cumulative) (ms): 32 bits Measurement Duration (Cumulative) (ms): 32 bits
The duration in ms of the reporting interval applicable to The duration in ms of the reporting interval applicable to
Cumulative reports which use this Measurement Identity block. Cumulative reports which use this Measurement Identity block.
Measurement Duration (Interval) (ms): 32 bits Measurement Duration (Interval) (ms): 32 bits
skipping to change at page 8, line 11 skipping to change at page 8, line 11
The duration in ms of the reporting interval applicable to The duration in ms of the reporting interval applicable to
Interval reports which use this Measurement Identity block. Interval reports which use this Measurement Identity block.
3. SDP Signaling 3. SDP Signaling
[RFC3611] defines the use of SDP (Session Description Protocol) [RFC3611] defines the use of SDP (Session Description Protocol)
[RFC4566] for signaling the use of XR blocks. XR blocks MAY be used [RFC4566] for signaling the use of XR blocks. XR blocks MAY be used
without prior signaling. without prior signaling.
This section augments the SDP [RFC4566] attribute "rtcp-xr" defined No additional SDP signaling is defined for this block. Instead, the
in [RFC3611] by providing a "xr-format" to signal the use of the need for this block SHOULD be inferred from a request in SDP
report block defined in this document. signalling for a block type (such as [DISCARD]) which depends on it.
The need for this block could be inferred from a request in SDP 4. IANA Considerations
signalling for a block type (such as [BASICLOSS]) which depends on
it. However to remove ambiguity, if SDP is used to signal a desire
to receive a block type which depends on the Measurement Identity
block, then the Measurement Identity block itself MUST be signalled
explicitly in SDP as described here.
rtcp-xr-attrib = "a=" "rtcp-xr" ":" [xr-format *(SP xr-format)] CRLF New block types for RTCP XR are subject to IANA registration. For
general guidelines on IANA considerations for RTCP XR, refer to
[RFC3611].
(defined in RFC3611) 4.1. New RTCP XR Block Type value
xr-format = xr-format / xr-mi-block This document assigns the block type value NMI in the IANA "RTCP XR
Block Type Registry" to the "Measurement Identity Block".
xr-mi-block = "xr-mi" [Note to RFC Editor: please replace NMI with the IANA provided RTCP
XR block type for this block.]
4. IANA Considerations 4.2. Contact information for registration
This document creates a new block type within the IANA "RTCP XR Block The contact information for the registration is:
Type Registry" called the Measurement Identity Block, and a new
parameter xr-mi within the "RTCP XR SDP Parameters Registry". Geoff Hunt (geoff.hunt@bt.com)
Orion 2 PP3, Adastral Park, Martlesham Heath, Ipswich IP5 3RE, United
Kingdom
5. Security Considerations 5. Security Considerations
RTCP reports can contain sensitive information since they can provide RTCP reports can contain sensitive information since they can provide
information about the nature and duration of a session established information about the nature and duration of a session established
between two or more endpoints. between two or more endpoints.
6. References 6. Changes since last version
6.1. Normative References Expanded and clarified IANA Considerations section
Changed to remove explicit SDP signalling for this block - need for
block is implicit if a metrics block is requested which depends on
this block.
Modified block structure to send first sequence number without
extension, rather than extend to 32-bit number with leading 16 bits
set to 0. These 16 bits are now reserved. Addresses Colin Perkins'
comment of 15-Nov-2008
Removed "forwarding count" field following Colin Perkins' request for
a use case. The field had been intended for use by translators to
establish the "distance" (as a count of forwarding systems) to the
point at which a measurement was made. However a recommendation to
increment the count could have forced forwarding translator devices
to parse the packet on a slow (CPU) path, possibly compromising RTCP
measurement of round-trip delay [RFC3550].
7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, BCP 14, March 1997. Requirement Levels", RFC 2119, BCP 14, March 1997.
[RFC3550] Schulzrinne, H., "RTP: A Transport Protocol for Real-Time [RFC3550] Schulzrinne, H., "RTP: A Transport Protocol for Real-Time
Applications", RFC 3550, July 2003. Applications", RFC 3550, July 2003.
[RFC3611] Friedman, T., "RTP Control Protocol Extended Reports (RTCP [RFC3611] Friedman, T., "RTP Control Protocol Extended Reports (RTCP
XR)", RFC 3611, November 2003. XR)", RFC 3611, November 2003.
[RFC4566] Handley, M., "SDP: Session Description Protocol", [RFC4566] Handley, M., "SDP: Session Description Protocol",
RFC 4566, July 2006. RFC 4566, July 2006.
6.2. Informative References 7.2. Informative References
[BASICLOSS] [DISCARD] Hunt, G., "RTCP XR Report Block for Discard metric
Hunt, G., "RTCP XR Block for Measurement Identity", Reporting", ID draft-ietf-avt-rtcp-xr-discard-01,
ID draft-ietf-avt-rtcp-xr-meas-identity-00, October 2008. February 2009.
[MONARCH] Hunt, G., "Monitoring Architectures for RTP", [MONARCH] Hunt, G., "Monitoring Architectures for RTP",
ID draft-hunt-avt-monarch-01, August 2008. ID draft-hunt-avt-monarch-01, August 2008.
[MPEG2] ISO/IEC, "Standard 13818-1", [MPEG2] ISO/IEC, "Standard 13818-1", December 2000.
ID draft-ietf-avt-rtcp-xr-meas-identity-00, December 2000.
[PMOLFRAME] [PMOLFRAME]
Clark, A., "Framework for Performance Metric Development", Clark, A., "Framework for Performance Metric Development",
ID draft-ietf-pmol-metrics-framework-00, July 2008. ID draft-ietf-pmol-metrics-framework-00, July 2008.
Authors' Addresses Authors' Addresses
Geoff Hunt Geoff Hunt
BT BT
Orion 1 PP9 Orion 2 PP3
Adastral Park Adastral Park
Martlesham Heath Martlesham Heath
Ipswich, Suffolk IP4 2TH Ipswich, Suffolk IP5 3RE
United Kingdom United Kingdom
Phone: +44 1473 608325 Phone: +44 1473 651704
Email: geoff.hunt@bt.com Email: geoff.hunt@bt.com
Alan Clark Alan Clark
Telchemy Incorporated Telchemy Incorporated
2905 Premiere Parkway, Suite 280 2905 Premiere Parkway, Suite 280
Duluth, GA 30097 Duluth, GA 30097
USA USA
Email: alan.d.clark@telchemy.com Email: alan.d.clark@telchemy.com
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