draft-ietf-xrblock-rtcp-xr-discard-03.txt   draft-ietf-xrblock-rtcp-xr-discard-04.txt 
Audio/Video Transport Working Group G. Hunt Audio/Video Transport Working Group G. Hunt
Internet-Draft Unaffiliated Internet-Draft Unaffiliated
Intended status: Standards Track A. Clark Intended status: Standards Track A. Clark
Expires: December 2, 2012 Telchemy Expires: December 31, 2012 Telchemy
G. Zorn G. Zorn
Network Zen Network Zen
Q. Wu Q. Wu
Huawei Huawei
May 31, 2012 June 29, 2012
RTCP XR Report Block for Discard metric Reporting RTCP XR Report Block for Discard Count metric Reporting
draft-ietf-xrblock-rtcp-xr-discard-03.txt draft-ietf-xrblock-rtcp-xr-discard-04.txt
Abstract Abstract
This document defines an RTCP XR Report Block that allows the This document defines an RTCP XR Report Block that allows the
reporting of a simple discard count metric for use in a range of RTP reporting of a simple discard count metric for use in a range of RTP
applications. applications.
Status of this Memo Status of this Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on December 2, 2012. This Internet-Draft will expire on December 31, 2012.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Discard Report Block . . . . . . . . . . . . . . . . . . . 3 1.1. Discard Count Report Block . . . . . . . . . . . . . . . . 3
1.2. RTCP and RTCP XR Reports . . . . . . . . . . . . . . . . . 3 1.2. RTCP and RTCP XR Reports . . . . . . . . . . . . . . . . . 3
1.3. Performance Metrics Framework . . . . . . . . . . . . . . 3 1.3. Performance Metrics Framework . . . . . . . . . . . . . . 3
1.4. Applicability . . . . . . . . . . . . . . . . . . . . . . 3 1.4. Applicability . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Standards Language . . . . . . . . . . . . . . . . . . . . 4 2.1. Standards Language . . . . . . . . . . . . . . . . . . . . 4
3. Discard Metric Report Block . . . . . . . . . . . . . . . . . 5 3. Discard Count Metric Report Block . . . . . . . . . . . . . . 5
3.1. Report Block Structure . . . . . . . . . . . . . . . . . . 5 3.1. Report Block Structure . . . . . . . . . . . . . . . . . . 5
3.2. Definition of Fields in Discard Metric Report Block . . . 5 3.2. Definition of Fields in Discard Metric Report Block . . . 5
4. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 7 4. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
5.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 8 5.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 8
5.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 8 5.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 8
5.3. Contact information for registrations . . . . . . . . . . 8 5.3. Contact information for registrations . . . . . . . . . . 8
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9 6. Security Considerations . . . . . . . . . . . . . . . . . . . 9
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
8.1. Normative References . . . . . . . . . . . . . . . . . . . 11 8.1. Normative References . . . . . . . . . . . . . . . . . . . 11
8.2. Informative References . . . . . . . . . . . . . . . . . . 11 8.2. Informative References . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction 1. Introduction
1.1. Discard Report Block 1.1. Discard Count 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. The new block type [RFC3611] for use in a range of RTP applications. The new block type
supports the reporting of the number of packets which are received supports the reporting of the number of packets which are received
correctly but are never played out, typically because they arrive too correctly but are never played out, typically because they arrive too
late to be played out (buffer underflow) or too early (buffer late to be played out (buffer underflow) or too early (buffer
overflow). The metric is applicable both to systems which use packet overflow). The metric is applicable both to systems which use packet
loss repair techniques (such as forward error correction [RFC5109] or loss repair techniques (such as forward error correction [RFC5109] or
retransmission [RFC4588]) and to those which do not. retransmission [RFC4588]) and to those which do not.
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The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
In addition, the following terms are defined: In addition, the following terms are defined:
Received, Lost and Discarded Received, Lost and Discarded
A packet shall be regarded as lost if it fails to arrive within an A packet shall be regarded as lost if it fails to arrive within an
implementation-specific time window. A packet that arrives within implementation-specific time window. A packet that arrives within
this time window but is too early or late to be played out shall this time window but is too early or late to be played out or
be regarded as discarded. A packet shall be classified as one of thrown away before playout (e.g., packet duplication or
received (or OK), discarded or lost. The Discard Metric counts redundancy) shall be regarded as discarded. A packet shall be
only discarded packets. The metric "cumulative number of packets classified as one of received (or OK), discarded or lost. The
lost" defined in [RFC3550] reports a count of packets lost from Discard Count Metric counts only discarded packets. The metric
the media stream (single SSRC within single RTP session). "cumulative number of packets lost" defined in [RFC3550] reports a
Similarly the metric "number of packets discarded" reports a count count of packets lost from the media stream (single SSRC within
of packets discarded from the media stream (single SSRC within single RTP session). Similarly the metric "number of packets
single RTP session) arriving at the receiver. Another metric discarded" reports a count of packets discarded from the media
defined in [RFC5725] is available to report on packets which are stream (single SSRC within single RTP session) arriving at the
not recovered by any repair techniques which may be in use. receiver. Another metric defined in [RFC5725] is available to
report on packets which are not recovered by any repair techniques
which may be in use.
3. Discard Metric Report Block 3. Discard Count Metric Report Block
3.1. Report Block Structure 3.1. 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=NBGD | I |DT | resv.| block length = 2 | | BT=PDC | I |DT | resv.| block length = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of Source | | SSRC of Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| number of packets discarded | | number of packets discarded |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Report Block Structure Figure 1: Report Block Structure
3.2. Definition of Fields in Discard Metric Report Block 3.2. Definition of Fields in Discard Metric Report Block
Block type (BT): 8 bits Block type (BT): 8 bits
A Discard Metric Report Block is identified by the constant ND. A Discard Count Metric Report Block is identified by the constant
PDC.
[Note to RFC Editor: please replace ND with the IANA provided RTCP [Note to RFC Editor: please replace PDC with the IANA provided
XR block type for this block.] RTCP XR block type for this block.]
Interval Metric flag (I): 2 bits Interval Metric flag (I): 2 bits
This field is used to indicate whether the Discard metric is an This field is used to indicate whether the Discard Count Metric is
Interval or Cumulative metric, that is, whether the reported an Interval or Cumulative metric, Sample metric,that is, whether
values applies to the most recent measurement interval duration the reported values applies to the most recent measurement
between successive metrics reports (I=10) (the Interval Duration) interval duration between successive metrics reports (I=10) (the
or to the accumulation period characteristic of cumulative Interval Duration) or to the accumulation period characteristic of
measurements (I=11) (the Cumulative Duration). cumulative measurements (I=11) (the Cumulative Duration) or is a
sampled instantaneous value (I=01) (Sampled Value). In this
document, Discard Count Metric is not measured at a particular
time instant but over one or several reporting intervals.
Therefore Discard Count Metric MUST not be chosen as Sampled
Metric.
Discard Type (DT): 2bits Discard Type (DT): 2bits
This field is used to identify the discard type used in this This field is used to identify the discard type used in this
report block. The discard type is defined as follows: report block. The discard type is defined as follows:
00: packets are discarded due to other reasons than late 00: Report packet discarded due to too early to be played out.
arrival, early arrival, or both (e.g., duplicate, redundant
packets).
01: packets are discarded due to too early arrival. 01: Report packet discarded due to too late to be played out.
10: packets are discarded due to too late arrival. 10: Report packet discarded due to both early and late to be
played out.
11: packets are discarded due to both early arrival and late 11: Report the total number of discarded packets in the
arrival. interval. The reasons to discard packet include too early to
be played out, too late to be playout,being thrown away before
playout.
Reserved (resv): 5 bits Reserved (resv): 5 bits
These bits are reserved. They SHOULD be set to zero by senders These bits are reserved. They SHOULD be set to zero by senders
and MUST be ignored by receivers. and MUST be ignored by receivers.
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 Delay block, the block length is equal to 2. the Delay block, the block length is equal to 2.
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SSRC of source: 32 bits SSRC of source: 32 bits
As defined in Section 4.1 of [RFC3611]. As defined in Section 4.1 of [RFC3611].
number of packets discarded: 32 bits number of packets discarded: 32 bits
Number of packets discarded over the period (Interval or Number of packets discarded over the period (Interval or
Cumulative) covered by this report. Cumulative) covered by this report.
If the measured value exceeds 0xFFFFFFFD, the value 0xFFFFFFFE If the measured value exceeds 0xFFFFFFFD, the value 0xFFFFFFFE
SHOULD be reported to indicate an over-range measurement. If the MUST be reported to indicate an over-range measurement. If the
measurement is unavailable, the value 0xFFFFFFFF MUST be reported. measurement is unavailable, the value 0xFFFFFFFF MUST be reported.
Note that the number of packets expected in the period covered by Note that the number of packets expected in the period covered by
the metric (whether interval or cumulative) is available from the the metric (whether interval or cumulative) is available from the
difference between a pair of extended sequence numbers in the difference between a pair of extended sequence numbers in the
Measurement Identity block, so need not be repeated in this block. Measurement Information block [MEASI], so need not be repeated in
this block.
4. SDP Signaling 4. 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 This section augments the SDP [RFC4566] attribute "rtcp-xr" defined
in [RFC3611] by providing an additional value of "xr-format" to in [RFC3611] by providing an additional value of "xr-format" to
signal the use of the report block defined in this document. signal the use of the report block defined in this document.
rtcp-xr-attrib = "a=" "rtcp-xr" ":" [xr-format *(SP xr-format)] CRLF rtcp-xr-attrib = "a=" "rtcp-xr" ":" [xr-format *(SP xr-format)] CRLF
(defined in [RFC3611]) (defined in [RFC3611])
xr-format =/ xr-pd-block xr-format =/ xr-pdc-block
xr-pd-block = "pkt-dscrd" xr-pdc-block = "pkt-dscrd-count"
5. IANA Considerations 5. IANA Considerations
New block types for RTCP XR are subject to IANA registration. For New block types for RTCP XR are subject to IANA registration. For
general guidelines on IANA considerations for RTCP XR, refer to general guidelines on IANA considerations for RTCP XR, refer to
[RFC3611]. [RFC3611].
5.1. New RTCP XR Block Type value 5.1. New RTCP XR Block Type value
This document assigns the block type value ND in the IANA "RTCP XR This document assigns the block type value PDC in the IANA "RTCP XR
Block Type Registry" to the "Discard Metrics Block". Block Type Registry" to the "Discard Count Metrics Block".
[Note to RFC Editor: please replace ND with the IANA provided RTCP XR [Note to RFC Editor: please replace PDC with the IANA provided RTCP
block type for this block.] XR block type for this block.]
5.2. New RTCP XR SDP Parameter 5.2. New RTCP XR SDP Parameter
This document also registers a new parameter "pkt-dscrd" in the "RTCP This document also registers a new parameter "pkt-dscrd" in the "RTCP
XR SDP Parameters Registry". XR SDP Parameters Registry".
5.3. Contact information for registrations 5.3. Contact information for registrations
The contact information for the registrations is: The following contact information is provided for all
registrations in this document:
Geoff Hunt (r.geoff.hunt@gmail.com) Geoff Hunt (r.geoff.hunt@gmail.com)
Orion 2 PP3, Adastral Park, Martlesham Heath, Ipswich IP5 3RE, United Orion 2 PP3, Adastral Park, Martlesham Heath, Ipswich IP5 3RE, United
Kingdom Kingdom
6. Security Considerations 6. Security Considerations
It is believed that this proposed RTCP XR report block introduces no It is believed that this proposed RTCP XR report block introduces no
new security considerations beyond those described in [RFC3611]. new security considerations beyond those described in [RFC3611].
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does not apply. does not apply.
7. Acknowledgments 7. Acknowledgments
The authors gratefully acknowledge the comments and contributions The authors gratefully acknowledge the comments and contributions
made by Bruce Adams, Philip Arden, Amit Arora, Bob Biskner, Kevin made by Bruce Adams, Philip Arden, Amit Arora, Bob Biskner, Kevin
Connor, Claus Dahm, Randy Ethier, Roni Even, Jim Frauenthal, Albert Connor, Claus Dahm, Randy Ethier, Roni Even, Jim Frauenthal, Albert
Higashi, Tom Hock, Shane Holthaus, Paul Jones, Rajesh Kumar, Keith Higashi, Tom Hock, Shane Holthaus, Paul Jones, Rajesh Kumar, Keith
Lantz, Mohamed Mostafa, Amy Pendleton, Colin Perkins, Mike Ramalho, Lantz, Mohamed Mostafa, Amy Pendleton, Colin Perkins, Mike Ramalho,
Ravi Raviraj, Albrecht Schwarz, Tom Taylor, and Hideaki Yamada,Kevin Ravi Raviraj, Albrecht Schwarz, Tom Taylor, and Hideaki Yamada,Kevin
Gross, Varun Singh. Gross, Varun Singh,Claire Bi, Roni Even, Dan Romascanu.
8. References 8. References
8.1. Normative References 8.1. 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", March 1997. Requirement Levels", 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., Caceres, R., and A. Clark, "RTP Control [RFC3611] Friedman, T., Caceres, R., and A. Clark, "RTP Control
Protocol Extended Reports (RTCP XR)", November 2003. Protocol Extended Reports (RTCP XR)", November 2003.
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
Description Protocol", July 2006. Description Protocol", July 2006.
8.2. Informative References 8.2. Informative References
[MEASI] Hunt, G., "Measurement Identity and information Reporting
using SDES item and XR Block",
ID draft-ietf-xrblock-rtcp-xr-meas-identity-06,
April 2012.
[MONARCH] Wu, Q., "Monitoring Architectures for RTP", [MONARCH] Wu, Q., "Monitoring Architectures for RTP",
ID draft-ietf-avtcore-monarch-12, April 2012. ID draft-ietf-avtcore-monarch-12, April 2012.
[RFC4588] Rey, J., "RTP Retransmission Payload Format", RFC 4588, [RFC4588] Rey, J., "RTP Retransmission Payload Format", RFC 4588,
July 2006. July 2006.
[RFC5109] Li, A., "RTP Payload Format for Generic Forward Error [RFC5109] Li, A., "RTP Payload Format for Generic Forward Error
Correction", RFC 5109, July 2006. Correction", RFC 5109, July 2006.
[RFC5725] Begen, A., "RTCP XR Report Block for Post-Repair Loss [RFC5725] Begen, A., "RTCP XR Report Block for Post-Repair Loss
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