draft-ietf-xrblock-rtcp-xr-discard-14.txt   draft-ietf-xrblock-rtcp-xr-discard-15.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: November 21, 2013 Network Zen Expires: December 30, 2013 Network Zen
Q. Wu Q. Wu
Huawei Huawei
May 20, 2013 June 28, 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-14.txt draft-ietf-xrblock-rtcp-xr-discard-15.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 November 21, 2013. This Internet-Draft will expire on December 30, 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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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 de-jitter buffer [RFC5481].
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
receivers to the need to adjust their transmission or reception receivers to the need to adjust their transmission or reception
strategies. The reports allow network managers to diagnose these strategies. The reports allow network managers to diagnose these
user experience problems. user experience problems.
The ability to detect duplicate packets can be used by managers to The ability to detect duplicate packets can be used by managers to
detect network layer or sender behavior which may indicate network or detect network layer or sender behavior which may indicate network or
device issues. Based on the reports, these issues may be addressed device issues. Based on the reports, these issues may be addressed
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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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| number of packets discarded | | discard count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Report Block Structure Figure 1: Report Block Structure
3.2. Definition of Fields in Discard Count Metric Report Block 3.2. Definition of Fields in Discard Count Metric Report Block
Block type (BT): 8 bits Block type (BT): 8 bits
A Discard Count Metric Report Block is identified by the constant A Discard Count Metric Report Block is identified by the constant
PDC. PDC.
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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 discard count
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.
The measured value is unsigned value. If the measured value The measured value is unsigned value. If the measured value
exceeds 0xFFFFFFFD, the value 0xFFFFFFFE MUST be reported to exceeds 0xFFFFFFFD, the value 0xFFFFFFFE MUST be reported to
indicate an over-range measurement. If the measurement is indicate an over-range measurement. If the measurement is
unavailable, the value 0xFFFFFFFF MUST be reported. unavailable, the value 0xFFFFFFFF MUST be reported.
Note that the number of packets expected in the period associated Note that the number of packets expected in the period associated
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XR 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-discard-count" in This document also registers a new parameter "pkt-discard-count" in
the " RTP Control Protocol Extended Reports (RTCP XR) Session the " RTP Control Protocol Extended Reports (RTCP XR) Session
Description Protocol (SDP) Parameters Registry ". Description Protocol (SDP) Parameters Registry ".
5.3. Contact information for registrations 5.3. Contact information for registrations
The following contact information is provided for all The following contact information is provided for all registrations
registrations in this document: in this document:
Qin Wu (sunseawq@huawei.com) Qin Wu (sunseawq@huawei.com)
101 Software Avenue, Yuhua District 101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012 Nanjing, Jiangsu 210012
China China
6. Security Considerations 6. Security Considerations
It is believed that this proposed RTCP XR report block introduces no In some situations, returning very detailed error information
new security considerations beyond those described in [RFC3611]. (e.g.,over-range measurement or measurement unavailable) using this
This block does not provide per-packet statistics so the risk to report block can provide an attacker with insight into the security
confidentiality documented in Section 7, paragraph 3 of [RFC3611] processing. Where this is a concern, the implementation should apply
does not apply. authentication to this report block. This can be achieved by using
the AVPF profile together with the Secure RTP profile as defined in
[RFC3711]; as a prerequisite, an appropriate combination of those two
profiles (an "SAVPF") is being specified [RFC5124].
Besides this, it is believed that this proposed RTCP XR report block
introduces no new security considerations beyond those described in
[RFC3611]. This block does not provide per-packet statistics so the
risk to confidentiality documented in Section 7, paragraph 3 of
[RFC3611] does not apply.
7. Contributors 7. Contributors
Geoff Hunt wrote the initial draft of this document. Geoff Hunt wrote the initial draft of this document.
8. Acknowledgments 8. Acknowledgments
The authors gratefully acknowledge reviews and feedback provided by The authors gratefully acknowledge reviews and feedback provided by
Bruce Adams, Philip Arden, Amit Arora, Bob Biskner, Kevin Connor, Bruce Adams, Philip Arden, Amit Arora, Bob Biskner, Kevin Connor,
Claus Dahm, Randy Ethier, Roni Even, Jim Frauenthal, Albert Higashi, Claus Dahm, Randy Ethier, Roni Even, Jim Frauenthal, Albert Higashi,
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