draft-ietf-xrblock-rtcp-xr-discard-12.txt   draft-ietf-xrblock-rtcp-xr-discard-13.txt 
Audio/Video Transport Working Group A. Clark Audio/Video Transport Working Group A. Clark
Internet-Draft Telchemy Internet-Draft Telchemy
Intended status: Standards Track G. Zorn Intended status: Standards Track G. Zorn
Expires: October 13, 2013 Network Zen Expires: October 29, 2013 Network Zen
Q. Wu Q. Wu
Huawei Huawei
April 11, 2013 April 27, 2013
RTP Control Protocol (RTCP) Extended Report (XR) Block for Discard Count RTP Control Protocol (RTCP) Extended Report (XR) Block for Discard Count
metric Reporting metric Reporting
draft-ietf-xrblock-rtcp-xr-discard-12.txt draft-ietf-xrblock-rtcp-xr-discard-13.txt
Abstract Abstract
This document defines an RTP Control Protocol(RTCP) Extended Report This document defines an RTP Control Protocol(RTCP) Extended Report
(XR) Block that allows the reporting of a simple discard count metric (XR) Block that allows the reporting of a simple discard count metric
for use in a range of RTP applications. for use in a range of RTP 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
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on October 13, 2013. This Internet-Draft will expire on October 29, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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5.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 10 5.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 10
5.3. Contact information for registrations . . . . . . . . . . 10 5.3. Contact information for registrations . . . . . . . . . . 10
6. Security Considerations . . . . . . . . . . . . . . . . . . . 11 6. Security Considerations . . . . . . . . . . . . . . . . . . . 11
7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 12 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 12
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
9.1. Normative References . . . . . . . . . . . . . . . . . . . 14 9.1. Normative References . . . . . . . . . . . . . . . . . . . 14
9.2. Informative References . . . . . . . . . . . . . . . . . . 14 9.2. Informative References . . . . . . . . . . . . . . . . . . 14
Appendix A. Metrics represented using RFC6390 Template . . . . . 15 Appendix A. Metrics represented using RFC6390 Template . . . . . 15
Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 16 Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 16
B.1. draft-ietf-xrblock-rtcp-xr-discard-12 . . . . . . . . . . 16 B.1. draft-ietf-xrblock-rtcp-xr-discard-13 . . . . . . . . . . 16
B.2. draft-ietf-xrblock-rtcp-xr-discard-11 . . . . . . . . . . 16 B.2. draft-ietf-xrblock-rtcp-xr-discard-12 . . . . . . . . . . 16
B.3. draft-ietf-xrblock-rtcp-xr-discard-10 . . . . . . . . . . 16 B.3. draft-ietf-xrblock-rtcp-xr-discard-11 . . . . . . . . . . 16
B.4. draft-ietf-xrblock-rtcp-xr-discard-09 . . . . . . . . . . 16 B.4. draft-ietf-xrblock-rtcp-xr-discard-10 . . . . . . . . . . 16
B.5. draft-ietf-xrblock-rtcp-xr-discard-08 . . . . . . . . . . 16 B.5. draft-ietf-xrblock-rtcp-xr-discard-09 . . . . . . . . . . 16
B.6. draft-ietf-xrblock-rtcp-xr-discard-08 . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction 1. Introduction
1.1. Discard Count Report Block 1.1. Discard Count Report Block
This document defines a new block type to augment those defined in This document 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
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This metric is useful for identifying the existence, and This metric is useful for identifying the existence, and
characterizing the severity, of a packet transport problem which may characterizing the severity, of a packet transport problem which may
affect users' perception of a service delivered over RTP. affect users' perception of a service delivered over RTP.
This block may be used in conjunction with [BGDISCARD] which provides This block may be used in conjunction with [BGDISCARD] which provides
additional information on the pattern of discarded packets. However additional information on the pattern of discarded packets. However
the metric in [BGDISCARD] may be used independently of the metrics in the metric in [BGDISCARD] may be used independently of the metrics in
this block. this block.
In case of Discard count Metrics Block sent together with Burst gap In case of Discard Count Metrics Block sent together with Burst Gap
discard Metrics Block defined in [BGDISCARD] to the media sender or Discard Metrics Block defined in [BGDISCARD] to the media sender or
RTP based network management system, information carried in the RTP based network management system, information carried in the
discard count Metrics Block and Burst gap discard Metrics Block Discard Count Metrics Block and Burst Gap Discard Metrics Block
allows them calculate the some bust gap summary statistics, e.g., gap allows them calculate the some bust gap summary statistics, e.g., gap
discard rate. discard rate.
The metric belongs to the class of transport-related end system The metric belongs to the class of transport-related end system
metrics defined in [RFC6792]. metrics defined in [RFC6792].
1.2. RTCP and RTCP XR Reports 1.2. RTCP and RTCP XR Reports
The use of RTCP for reporting is defined in [RFC3550]. [RFC3611] The use of RTCP for reporting is defined in [RFC3550]. [RFC3611]
defined an extensible structure for reporting using an RTCP Extended defined an extensible structure for reporting using an RTCP Extended
Report (XR). This document defines a new Extended Report block for Report (XR). This document defines a new Extended Report block for
use with [RFC3550] and [RFC3611]. use with [RFC3550] and [RFC3611].
1.3. Performance Metrics Framework 1.3. Performance Metrics Framework
The Performance Metrics Framework [RFC6390] provides guidance on the The Performance Metrics Framework [RFC6390] provides guidance on the
definition and specification of performance metrics. The RTP definition and specification of performance metrics. The RTP
Monitoring Architectures [RFC6792] provides guideline for reporting Monitoring Architectures [RFC6792] provides guideline for reporting
block format using RTCP XR. The Metrics Block described in this block format using RTCP XR. The metrics block described in this
document are in accordance with the guidelines in [RFC6390] and document are in accordance with the guidelines in [RFC6390] and
[RFC6792]. [RFC6792].
1.4. Applicability 1.4. Applicability
This metric is believed to be applicable to a large class of RTP This metric is believed to be applicable to a large class of RTP
applications which use a jitter buffer. applications which use a jitter buffer.
Discards due to late or early arriving packets affects user Discards due to late or early arriving packets affects user
experience. The reporting of discards alerts senders and other experience. The reporting of discards alerts senders and other
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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 or this time window but is either too early to be played out or too
thrown away before playout due to packet duplication or redundancy late to be played out or thrown away before playout due to packet
shall be regarded as discarded. A packet shall be classified as duplication or redundancy shall be regarded as discarded. A
one of received (or OK), discarded or lost. The Discard Count packet shall not be regarded as discarded if it arrives within
Metric counts only discarded packets. The metric "cumulative this time window but is dropped during decoding by some higher
number of packets lost" defined in [RFC3550] reports a count of layer decoder, e.g., due to a decoding error. A packet shall be
packets lost from the media stream (single SSRC within single RTP classified as one of received (or OK), discarded or lost. The
session). Similarly the metric "number of packets discarded" Discard Count Metric counts only discarded packets. The metric
reports a count of packets discarded from the media stream (single "cumulative number of packets lost" defined in [RFC3550] reports a
SSRC within single RTP session) arriving at the receiver. Another count of packets lost from the media stream (single
metric defined in [RFC5725] is available to report on packets Synchronization source (SSRC) within single RTP session).
which are not recovered by any repair techniques which may be in Similarly the metric "number of packets discarded" reports a count
use. of packets discarded from the media stream (single SSRC within
single RTP session) arriving at the 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 Count Metric Report Block 3. Discard Count Metric Report Block
Metrics in this block report on the number of packets discarded in Metrics in this block report on the number of packets discarded in
the stream arriving at the RTP end system. The measurement of these the stream arriving at the RTP end system. The measurement of these
metrics is made at the receiving end of the RTP stream. Instances of metrics is made at the receiving end of the RTP stream. Instances of
this Metrics Block refer by SSRC to the separate auxiliary this metrics block refer by SSRC to the separate auxiliary
Measurement Information block [RFC6776] which describes measurement Measurement Information Block [RFC6776] which describes measurement
Intervals in use. This Metrics Block relies on the measurement Intervals in use. This metrics block relies on the measurement
interval in the Measurement Information block indicating the span of interval in the Measurement Information Block indicating the span of
the report and MUST be sent in the same compound RTCP packet as the the report and MUST be sent in the same compound RTCP packet as the
measurement information block. If the measurement interval is not measurement information block. If the measurement interval is not
received in the same compound RTCP packet as this Metrics Block, this received in the same compound RTCP packet as this metrics block, this
Metrics Block MUST be discarded. metrics block MUST be discarded.
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 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BT=PDC | I |DT | resv.| block length = 2 | | BT=PDC | I |DT | resv.| block length = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of Source | | SSRC of Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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A Discard Count Metric Report Block is identified by the constant A Discard Count Metric Report Block is identified by the constant
PDC. PDC.
[Note to RFC Editor: please replace PDC with the IANA provided [Note to RFC Editor: please replace PDC with the IANA provided
RTCP 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 indicates whether the reported metric is an interval, This field indicates whether the reported metric is an interval,
cumulative, or sampled metric [RFC6792]. The Discard Count Metric cumulative, or sampled metric [RFC6792]:
can only be measured over definite intervals, and cannot be
sampled. Accordingly, the value I=01, indicating a sampled value, I=10: Interval Duration - the reported value applies to the
MUST NOT be sent, and MUST be discarded when received. In most recent measurement interval duration between successive
addition, the value I=00 is reserved and also MUST NOT be sent, metrics reports.
and MUST be discarded when received.
I=11: Cumulative Duration - the reported value applies to the
accumulation period characteristic of cumulative measurements.
I=01: Sampled Value - the reported value is a sampled
instantaneous value.
In this document, the Discard Count Metric can only be measured
over definite intervals, and cannot be sampled. Accordingly, the
value I=01, indicating a sampled value, MUST NOT be sent, and MUST
be discarded when received. In addition, the value I=00 is
reserved and also MUST NOT be sent, and MUST be discarded when
received.
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: Report packet discarded or being thrown away before playout 00: Report packet discarded or being thrown away before playout
due to packets duplication. due to packets duplication.
01: Report packet discarded due to too early to be played out. 01: Report packet discarded due to too early to be played out.
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cause breakage of RTP streams or RTCP statistics. cause breakage of RTP streams or RTCP statistics.
Reserved (resv): 4 bits Reserved (resv): 4 bits
These bits are reserved. They MUST be set to zero by senders and These bits are reserved. They MUST be set to zero by senders and
ignored by receivers (See RFC6709 section 4.2). ignored by receivers (See RFC6709 section 4.2).
block length: 16 bits block length: 16 bits
The length of this report block in 32-bit words, minus one, in The length of this report block in 32-bit words, minus one, in
accordance with the definition in[RFC3611] . This field MUST be accordance with the definition in [RFC3611]. This field MUST be
set to 2 to match the fixed length of the report block. The block set to 2 to match the fixed length of the report block. The block
MUST be discarded if the block length is set to a different value. MUST be discarded if the block length is set to a different value.
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
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[RFC4566] for signaling the use of XR blocks. However XR blocks MAY [RFC4566] for signaling the use of XR blocks. However XR blocks MAY
be used without prior signaling (see section 5 of RFC3611). be used without prior signaling (see section 5 of RFC3611).
4.1. SDP rtcp-xr-attrib Attribute Extension 4.1. SDP rtcp-xr-attrib Attribute Extension
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.
xr-format =/ xr-pdc-block xr-format =/ xr-pdc-block
xr-pdc-block = "pkt-discard-count"
xr-pdc-block = "pkt-discard-count"
4.2. Offer/Answer Usage 4.2. Offer/Answer Usage
When SDP is used in offer-answer context, the SDP Offer/Answer usage When SDP is used in offer-answer context, the SDP Offer/Answer usage
defined in [RFC3611] for unilateral "rtcp-xr" attribute parameters defined in [RFC3611] for unilateral "rtcp-xr" attribute parameters
applies. For detailed usage of Offer/Answer for unilateral applies. For detailed usage of Offer/Answer for unilateral
parameter, refer to section 5.2 of [RFC3611]. parameter, refer to section 5.2 of [RFC3611].
5. IANA Considerations 5. IANA Considerations
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September 2012. September 2012.
[RFC6776] Hunt, G., "Measurement Identity and information Reporting [RFC6776] Hunt, G., "Measurement Identity and information Reporting
using SDES item and XR Block", RFC 6776, October 2012. using SDES item and XR Block", RFC 6776, October 2012.
9.2. Informative References 9.2. Informative References
[BGDISCARD] [BGDISCARD]
Hunt, G., "RTCP XR Report Block for Burst Gap Discard Hunt, G., "RTCP XR Report Block for Burst Gap Discard
metric Reporting", metric Reporting",
ID draft-ietf-xrblock-rtcp-xr-burst-gap-discard-11, ID draft-ietf-xrblock-rtcp-xr-burst-gap-discard-14,
April 2013. April 2013.
[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
metric Reporting", RFC 5725, February 2010. metric Reporting", RFC 5725, February 2010.
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* Use and applications: See section 1.4 [RFCXXXX]. * Use and applications: See section 1.4 [RFCXXXX].
* Reporting model: See RFC3611. * Reporting model: See RFC3611.
Appendix B. Change Log Appendix B. Change Log
Note to the RFC-Editor: please remove this section prior to Note to the RFC-Editor: please remove this section prior to
publication as an RFC. publication as an RFC.
B.1. draft-ietf-xrblock-rtcp-xr-discard-12 B.1. draft-ietf-xrblock-rtcp-xr-discard-13
The following are the major changes compared to previous version:
o Some editorial changes to get in line with burst gap drafts.
B.2. draft-ietf-xrblock-rtcp-xr-discard-12
The following are the major changes compared to previous version: The following are the major changes compared to previous version:
o Incorporate some changes to burst gap draft that applies to this o Incorporate some changes to burst gap draft that applies to this
document. document.
o Use RFC6390 template to the metrics in the appendix. o Use RFC6390 template to the metrics in the appendix.
B.2. draft-ietf-xrblock-rtcp-xr-discard-11 B.3. draft-ietf-xrblock-rtcp-xr-discard-11
The following are the major changes compared to previous version: The following are the major changes compared to previous version:
o Editorial change t based on SDP Directorate and Colin's Review. o Editorial change t based on SDP Directorate and Colin's Review.
B.3. draft-ietf-xrblock-rtcp-xr-discard-10 B.4. draft-ietf-xrblock-rtcp-xr-discard-10
The following are the major changes compared to previous version: The following are the major changes compared to previous version:
o Editorial change to get in line with recently discussed drafts. o Editorial change to get in line with recently discussed drafts.
o Remove DT=3 based on the discussion to summary statistics draft. o Remove DT=3 based on the discussion to summary statistics draft.
B.4. draft-ietf-xrblock-rtcp-xr-discard-09 B.5. draft-ietf-xrblock-rtcp-xr-discard-09
The following are the major changes compared to previous version: The following are the major changes compared to previous version:
o SDP Duplicated Parameter Deleting. o SDP Duplicated Parameter Deleting.
B.5. draft-ietf-xrblock-rtcp-xr-discard-08 B.6. draft-ietf-xrblock-rtcp-xr-discard-08
The following are the major changes compared to previous version: The following are the major changes compared to previous version:
o Outdated reference update. o Outdated reference update.
o Editorial changes based on comments that applied to PDV and Delay o Editorial changes based on comments that applied to PDV and Delay
drafts. drafts.
Authors' Addresses Authors' Addresses
 End of changes. 20 change blocks. 
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