Audio/Video Transport Working Group G. Hunt
Internet-Draft Unaffiliated
Intended status: Standards Track A. Clark
Expires: July 15, 2012 Telchemy
Q. Wu
Huawei
January 12, 2012
Measurement Identity and information Reporting using SDES item and XR
Block
draft-ietf-xrblock-rtcp-xr-meas-identity-02.txt
Abstract
This document defines a RTCP SDES item and a RTCP XR Block carrying
parameters which identify a measurement, to which one or more other
RTCP XR Report Blocks may refer.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. RTCP and RTCP XR Reports . . . . . . . . . . . . . . . . . 4
1.2. Performance Metrics Framework . . . . . . . . . . . . . . 4
1.3. Applicability . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1. Standards Language . . . . . . . . . . . . . . . . . . . . 5
3. Measurement Identity SDES Item . . . . . . . . . . . . . . . . 6
3.1. APSI: Application Specific Identifier SDES Item . . . . . 6
4. Measurement Information XR Block . . . . . . . . . . . . . . . 7
4.1. Report Block Structure . . . . . . . . . . . . . . . . . . 7
4.2. Definition of Fields in Measurement Information Report
Block . . . . . . . . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
5.1. New RTCP SDES Type value . . . . . . . . . . . . . . . . . 9
5.2. New RTCP XR Block Type value . . . . . . . . . . . . . . . 9
5.3. Contact information for registrations . . . . . . . . . . 9
6. Security Considerations . . . . . . . . . . . . . . . . . . . 10
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.1. Normative References . . . . . . . . . . . . . . . . . . . 11
7.2. Informative References . . . . . . . . . . . . . . . . . . 11
Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 12
A.1. draft-ietf-xrblock-xr-rtcp-meas-identity-00 . . . . . . . 12
A.2. draft-ietf-xrblock-xr-rtcp-meas-identity-01 . . . . . . . 12
A.3. draft-ietf-xrblock-xr-rtcp-meas-identity-02 . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14
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1. Introduction
This draft defines one new RTCP SDES item and one new XR Report Block
to carry parameters which identify a measurement for use in a range
of RTP applications. The XR Report Block and the SDES item do not
contain any measurement results (metrics). However, the XR Report
Block provides information relevant to a measurement reported in one
or more other block types, including
o the sequence number of the first packet of the RTP session,
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 interval applicable to cumulative measurements
(which may be the duration of the RTP session to date).
The method for calculation of the extended RTP sequence number is
provide in [RFC3550].
And the SDES item provides a measurement identity reported in one or
more other block types, i.e.,a field for incorporation of an
application-specific auxiliary identifier,
The RTCP SDES item containing the measurement identity is intended to
provide information to relate RTP to a non-RTP session while the RTCP
XR Report Block containing the measurement information is intended to
provide a single copy of the information necessary to relate
measurement data in the RTCP XR blocks to the stream, and measurement
period, to which they refer. Commonly, multiple other small metric
blocks contain measurement data for the same stream and period, and
it would be a large overhead if all of these metric blocks carried
duplicated data for measurement identification.
A RTCP Measurement Identity SDES packet MAY be associated with a set
of RTCP XR metrics blocks which share the same application specific
measurement identifier.
The RTCP XR Report Block MAY be associated with a set of RTCP XR
metrics blocks which share the same information relevant to a
reported measurement. There MAY be several such sets in an RTCP
packet, in which each set share the same information relevant to a
reported measurement. There MAY also be RTCP XR blocks in the packet
which are not associated with a Measurement Information block, for
example blocks which were defined before the Measurement Identity and
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information mechanism was introduced by this document.
1.1. 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 draft defines a new Extended Report block that
MUST be used as defined in [RFC3550] and [RFC3611].
1.2. Performance Metrics Framework
The Performance Metrics Framework [RFC6390] provides guidance on the
definition and specification of performance metrics. The RTP
Monitoring Architectures[MONARCH] provides guideline for reporting
block format using RTCP XR . Metrics or the SDES item described in
this draft either reference external definitions or define metrics
generally in accordance with [RFC6390] and [MONARCH].
1.3. Applicability
The RTCP SDES item and the RTCP XR block defined in this document
provides information relevant to the measurement for members of a
family of RTCP XR metrics blocks which are designed to use it. To
use the mechanism defined here, the RTCP XR block containing
measurement information is not required to be in the same RTCP packet
as the SDES item containing measurement identity.
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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]
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3. Measurement Identity SDES Item
This section defines the format of Measurement Identity SDES item.
The SDES item is carried in the RTCP SDES packet. The packet format
for the RTCP SDES is defined in Section 6.5 of [RFC3550]. Each SDES
packet is composed of a header with fixed-length fields for version,
source count, packet type (PT), and length, followed by zero of more
SDES items. In the SDES packet, the PT field is set to SDES (202).
3.1. APSI: Application Specific Identifier SDES Item
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| APSI=TBD | length |application specific identifier
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ....
+-+-+-+-+-+-+-+-+
Application specific identifier is an additional identifier which is
useful in the context of a specific application, e.g. an MPEG-2
transport identifier [MPEG2]. The identifier is variable length.
Its length is described by the length field. The value of the length
field does not include the two octet SDES item header. If no
identifier is provided, the length field MUST be set to zero. This
item MUST be ignored by applications that are not configured to make
use of it.
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4. Measurement Information XR Block
4.1. Report Block Structure
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 | Reserved | block length = 6 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of stream source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | first sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| extended first sequence number of interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| extended last sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Measurement Duration (Cumulative) (ms) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Measurement Duration (Interval) (ms) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Report Block Structure
4.2. Definition of Fields in Measurement Information Report Block
Block type (BT): 8 bits
A Measurement Information Report Block is identified by the
constant NMI.
[Note to RFC Editor: please replace NMI 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
MUST be ignored by the receiver.
Block Length: 16 bits
The length of this report block in 32-bit words minus one. For
the Measurement Information block, the block length is equal to 6.
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SSRC of source: 32 bits
As defined in Section 4.1 of [RFC3611].
Reserved: 16 bits
These bits are reserved. They MUST be ignored by receivers. They
MUST be set to zero by senders.
First sequence number: 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
The extended RTP sequence number of the first received RTP packet
of the current measurement interval.
Extended last sequence number: 32 bits
The extended RTP sequence number of the last received RTP packet
which contributed to this measurement.
Measurement Duration (Cumulative) (ms): 32 bits
The duration in ms of the reporting interval applicable to
Cumulative reports which use this Measurement Information block.
The value of this field can be calculated by receiver, for
example, based on received RTP media packets or using RTCP method
described in [RFC3550].
Measurement Duration (Interval) (ms): 32 bits
The duration in ms of the reporting interval applicable to
Interval reports which use this Measurement Information block.
The value of this field can be calculated by receiver, for
example, based on received RTP media packets or using RTCP method
described in [RFC3550].
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5. IANA Considerations
New SDES types for RTCP SDES are subject to IANA registration. For
general guidelines on IANA considerations for RTCP SDES, refer to
[RFC3550].
5.1. New RTCP SDES Type value
This document assigns one additional SDES type in the IANA "RTCP XR
Block Type Registry" to the Measurement Identity SDES items as
follow:
abbrev. name value
APSI: Application Specific Identifier TBD
[Note to RFC Editor: please replace APSI with the IANA provided RTCP
SDES type for the SDES item.]
5.2. New RTCP XR Block Type value
This document assigns the block type value NMI in the IANA "RTCP XR
Block Type Registry" to the "Measurement Information Block".
[Note to RFC Editor: please replace NMI with the IANA provided RTCP
XR block type for this block.]
5.3. Contact information for registrations
The contact information for the registrations is:
Qin Wu (sunseawq@huawei.com)
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
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6. Security Considerations
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. Therefore, the use of security
mechanisms with RTP documented in Section 9 of [RFC3550] should
apply.
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7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", March 1997.
[RFC3550] Schulzrinne, H., "RTP: A Transport Protocol for Real-Time
Applications", RFC 3550, July 2003.
[RFC3611] Friedman, T., Caceres, R., and A. Clark, "RTP Control
Protocol Extended Reports (RTCP XR)", November 2003.
7.2. Informative References
[MONARCH] Wu, Q., "Monitoring Architectures for RTP",
ID draft-ietf-avtcore-monarch-04, August 2011.
[MPEG2] "ISO/IEC, "Standard 13818-1"", December 2000.
[RFC6390] Clark, A. and B. Claise, "Framework for Performance Metric
Development", RFC 6390, October 2011.
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Appendix A. Change Log
Note to the RFC-Editor: please remove this section prior to
publication as an RFC.
A.1. draft-ietf-xrblock-xr-rtcp-meas-identity-00
The following are the major changes to
draft-ietf-avt-rtcp-xr-meas-identity-02:
o Change the use of SDES item to convey measurement identity instead
of XR Block in section 2.
o Update references.
o Update security section and remove SDP signaling section.
A.2. draft-ietf-xrblock-xr-rtcp-meas-identity-01
The following are the major changes to
draft-ietf-xrblock-xr-rtcp-meas-identity-00:
o Replace SDES item containing additional measurement information
with XR Block.
o Add section 2 to describe following RFC2119 language.
o Add Section 1.2 to make SDES item and XR Report be compliant with
RFC3550 and RFC3611
o Add Section 1.3 to make SDES item and XR Report follow Performance
Metrics Framework and RTP Monitoring Architecture.
o Add section5.2 to register the new RTCP XR Block Type value.
o Remove RTCP SDES Type values that are needed.
A.3. draft-ietf-xrblock-xr-rtcp-meas-identity-02
The following are the major changes to
draft-ietf-xrblock-xr-rtcp-meas-identity-01:
o Relocating information that belong to SDES item and XR Block
respectively in the section 1.
o Rephrasing the text that describes SDES packet composition.
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o Rephrasing identifier description.
o Other Editorial changes.
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Authors' Addresses
Geoff Hunt
Unaffiliated
Email: r.geoff.hunt@gmail.com
Alan Clark
Telchemy Incorporated
2905 Premiere Parkway, Suite 280
Duluth, GA 30097
USA
Email: alan.d.clark@telchemy.com
Qin Wu
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: sunseawq@huawei.com
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