draft-ietf-xrblock-rtcp-xr-synchronization-04.txt   draft-ietf-xrblock-rtcp-xr-synchronization-05.txt 
Network Working Group H. Asaeda Network Working Group H. Asaeda
Internet-Draft NICT Internet-Draft NICT
Intended status: Standards Track R. Huang Intended status: Standards Track R. Huang
Expires: October 5, 2013 Q. Wu Expires: November 25, 2013 Q. Wu
Huawei Huawei
April 3, 2013 May 24, 2013
RTP Control Protocol (RTCP) Extended Report (XR) Blocks for RTP Control Protocol (RTCP) Extended Report (XR) Blocks for
Synchronization Delay and Offset Metrics Reporting Synchronization Delay and Offset Metrics Reporting
draft-ietf-xrblock-rtcp-xr-synchronization-04 draft-ietf-xrblock-rtcp-xr-synchronization-05
Abstract Abstract
This document defines two RTP Control Protocol (RTCP) Extended Report This document defines two RTP Control Protocol (RTCP) Extended Report
(XR) Blocks that allow the reporting of synchronization delay and (XR) Blocks that allow the reporting of synchronization delay and
offset metrics for use in a range of RTP applications. offset metrics 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 5, 2013. This Internet-Draft will expire on November 25, 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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5.1. SDP rtcp-xr-attrib Attribute Extension . . . . . . . . . . 9 5.1. SDP rtcp-xr-attrib Attribute Extension . . . . . . . . . . 9
5.2. Offer/Answer Usage . . . . . . . . . . . . . . . . . . . . 9 5.2. Offer/Answer Usage . . . . . . . . . . . . . . . . . . . . 9
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
7. Security Considerations . . . . . . . . . . . . . . . . . . . 10 7. Security Considerations . . . . . . . . . . . . . . . . . . . 10
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
9.1. Normative References . . . . . . . . . . . . . . . . . . . 11 9.1. Normative References . . . . . . . . . . . . . . . . . . . 11
9.2. Informative References . . . . . . . . . . . . . . . . . . 11 9.2. Informative References . . . . . . . . . . . . . . . . . . 11
Appendix A. Metrics represented using RFC6390 Template . . . . . 12 Appendix A. Metrics represented using RFC6390 Template . . . . . 12
Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 13 Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 13
B.1. draft-ietf-xrblock-rtcp-xr-syncronization-04 . . . . . . . 13 B.1. draft-ietf-xrblock-rtcp-xr-syncronization-05 . . . . . . . 13
B.2. draft-ietf-xrblock-rtcp-xr-syncronization-03 . . . . . . . 13 B.2. draft-ietf-xrblock-rtcp-xr-syncronization-04 . . . . . . . 13
B.3. draft-ietf-xrblock-rtcp-xr-syncronization-02 . . . . . . . 13 B.3. draft-ietf-xrblock-rtcp-xr-syncronization-03 . . . . . . . 13
B.4. draft-ietf-xrblock-rtcp-xr-syncronization-02 . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction 1. Introduction
1.1. Synchronization Delay and Offset Metrics Reporting Blocks 1.1. Synchronization Delay and Offset Metrics Reporting Blocks
This draft defines two new block types to augment those defined in This document defines two new block types to augment those defined in
[RFC3611], for use in a range of RTP applications. [RFC3611], for use in a range of RTP applications.
The first new block type supports reporting of Initial The first new block type supports reporting of Initial
Synchronization Delay to establish multimedia session. Information Synchronization Delay to establish multimedia session. Information
is recorded about time difference between the start of RTP sessions is recorded about time difference between the start of RTP sessions
and the time the RTP receiver acquires all components of RTP sessions and the time the RTP receiver acquires all components of RTP sessions
in the multimedia session [RFC6051]. in the multimedia session [RFC6051].
The second new block type supports reporting of the relative The second new block type supports reporting of the relative
synchronization offset time of two arbitrary streams (e.g., between synchronization offset time of two arbitrary streams (e.g., between
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.2. Definition of Fields in RTP Flow Initial Synchronization Delay 3.2. Definition of Fields in RTP Flow Initial Synchronization Delay
Metrics Block Metrics Block
Block type (BT): 8 bits Block type (BT): 8 bits
The RTP Flows Initial Synchronization Delay Report Block is The RTP Flows Initial Synchronization Delay Report Block is
identified by the constant <RFISD>. identified by the constant <RFISD>.
Reserved: 6 bits Reserved: 8 bits
This field is reserved for future definition. In the absence of 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 such a definition, the bits in this field MUST be set to zero and
MUST be ignored by the receiver. ignored by the receiver.
Block length: 16 bits Block length: 16 bits
The constant 2, in accordance with the definition of this field in The constant 2, in accordance with the definition of this field in
Section 3 of RFC 3611 [RFC3611]. Section 3 of RFC 3611 [RFC3611].
SSRC of source: 32 bits SSRC of source: 32 bits
The SSRC of the media source SHALL be set to the value of the SSRC The SSRC of the media source SHALL be set to the value of the SSRC
identifier carried in any arbitrary component of RTP sessions identifier carried in any arbitrary component of RTP sessions
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recommended that the beginning of multimedia session is chosen as recommended that the beginning of multimedia session is chosen as
the time when the receiver has joined the first RTP session of the the time when the receiver has joined the first RTP session of the
multimedia session. The value of the initial synchronization multimedia session. The value of the initial synchronization
delay is calculated based on received RTCP SR packets or the RTP delay is calculated based on received RTCP SR packets or the RTP
header extension containing in-band mapping of RTP and NTP-format header extension containing in-band mapping of RTP and NTP-format
timestamps [RFC6051]. If there is no packet loss, the initial timestamps [RFC6051]. If there is no packet loss, the initial
synchronization delay is expected to be equal to the average time synchronization delay is expected to be equal to the average time
taken to receive the first RTCP packet in the RTP session with the taken to receive the first RTCP packet in the RTP session with the
longest RTCP reporting interval or the average time taken to longest RTCP reporting interval or the average time taken to
receive the first RTP header extension containing in-band mapping receive the first RTP header extension containing in-band mapping
of RTP and NTP- format timestamps. of RTP and NTP-format timestamps.
If the measurement is unavailable, the value of this field with If the measurement is unavailable, the value of this field with
all bits set to 1 MUST be reported. all bits set to 1 MUST be reported.
4. RTP Flows Synchronization Offset Metrics Block 4. RTP Flows Synchronization Offset Metrics Block
In the RTP multimedia sessions or one RTP session, there can be an In the RTP multimedia sessions or one RTP session, there can be an
arbitrary number of Media streams and each media stream (e.g., audio arbitrary number of Media streams and each media stream (e.g., audio
stream or video stream) is sent in a separate RTP stream. In case of stream or video stream) is sent in a separate RTP stream. In case of
one RTP session, each media stream or each medium uses different one RTP session, each media stream or each medium uses different
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discarded. discarded.
4.1. Metric Block Structure 4.1. Metric Block Structure
The RTP Flow General Synchronization Offset Report Block has the The RTP Flow General Synchronization Offset Report Block has the
following format: following format:
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=RFSO | I | Reserved | Block length=4 | | BT=RFSO | I | Reserved | Block length=3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of source | | SSRC of source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Synchronization Offset, most significant word | | Synchronization Offset, most significant word |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Synchronization Offset, least significant word | | Synchronization Offset, least significant word |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4.2. Definition of Fields in RTP Flow General Synchronization Offset 4.2. Definition of Fields in RTP Flow General Synchronization Offset
Metrics Block Metrics Block
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the value of the synchronization offset D may be expressed as the value of the synchronization offset D may be expressed as
D(i,j) = (Rj - Ri) - (Sj - Si) = (Rj - Sj) - (Ri - Si) D(i,j) = (Rj - Ri) - (Sj - Si) = (Rj - Sj) - (Ri - Si)
If in-band delivery of NTP-format timestamps is supported If in-band delivery of NTP-format timestamps is supported
[RFC6051], Si and Sj should be obtained directly from the RTP [RFC6051], Si and Sj should be obtained directly from the RTP
packets where NTP timestamps are available. If not, Si and Sj packets where NTP timestamps are available. If not, Si and Sj
should be calculated from their corresponding RTP timestamps. The should be calculated from their corresponding RTP timestamps. The
value of the synchronization offset is represented using a 64-bit value of the synchronization offset is represented using a 64-bit
signed NTP-format timestamp as defined in [RFC5905], which is 64- signed NTP-format timestamp as defined in [RFC5905], which is 64-
bit signed fixed-point number with the integer part in the first bit signed fixed-point number with the integer part in the first
32 bits and the fractional part in the last 32 bits. . A positive 32 bits and the fractional part in the last 32 bits. A positive
value of the synchronization offset means that the reporting value of the synchronization offset means that the reporting
stream leads before the reference stream, while a negative one stream leads before the reference stream, while a negative one
means the reporting stream lags behind the reference stream. The means the reporting stream lags behind the reference stream. The
synchronization offset of zero means the stream is the reference synchronization offset of zero means the stream is the reference
stream. stream.
If the measurement is unavailable, the value of this field with If the measurement is unavailable, the value of this field with
all bits set to 1 MUST be reported. all bits set to 1 MUST be reported.
5. SDP Signaling 5. SDP Signaling
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Two new parameters are defined for the two report blocks defined in Two new parameters are defined for the two report blocks defined in
this document to be used with Session Description Protocol (SDP) this document to be used with Session Description Protocol (SDP)
[RFC4566] using the Augmented Backus-Naur Form (ABNF) [RFC5234]. [RFC4566] using the Augmented Backus-Naur Form (ABNF) [RFC5234].
They have the following syntax within the "rtcp-xr" attribute They have the following syntax within the "rtcp-xr" attribute
[RFC3611]: [RFC3611]:
xr-format = xr-rfisd-block xr-format = xr-rfisd-block
/ xr-rfso-block / xr-rfso-block
xr-rfisd-block = " init-syn-delay" xr-rfisd-block = " rtp-flow-init-syn-delay"
xr-rfso-block = " syn-offset" xr-rfso-block = " rtp-flow-syn-offset"
Refer to Section 5.1 of RFC 3611 [RFC3611] for a detailed description Refer to Section 5.1 of RFC 3611 [RFC3611] for a detailed description
and the full syntax of the "rtcp-xr" attribute. and the full syntax of the "rtcp-xr" attribute.
5.2. Offer/Answer Usage 5.2. 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] applies. defined in [RFC3611] applies.
6. IANA Considerations 6. IANA Considerations
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* Reporting model: See RFC3611. * Reporting model: See RFC3611.
b. Synchronization Offset Metric b. Synchronization Offset Metric
* Metric Name: RTP Synchronization Offset Delay * Metric Name: RTP Synchronization Offset Delay
* Metric Description: See Section 2.1, Synchronization Offset * Metric Description: See Section 2.1, Synchronization Offset
term [RFCXXXX]. term [RFCXXXX].
* Method of Measurement or Calculation: See section 4.2, Initial * Method of Measurement or Calculation: See section 4.2, Initial
Synchronization Delay definition definition [RFCXXXX]. Synchronization Delay definition [RFCXXXX].
* Units of Measurement: See section 4.2, Initial Synchronization * Units of Measurement: See section 4.2, Initial Synchronization
Delay definition definition [RFCXXXX]. Delay definition [RFCXXXX].
* Measurement Point(s) with Potential Measurement Domain: See * Measurement Point(s) with Potential Measurement Domain: See
section 4, 2nd paragraph [RFCXXXX]. section 4, 2nd paragraph [RFCXXXX].
* Measurement Timing: See section 4, 3rd paragraph [RFCXXXX] for * Measurement Timing: See section 4, 3rd paragraph [RFCXXXX] for
measurement timing and section 4.2 [RFCXXXX] for Interval measurement timing and section 4.2 [RFCXXXX] for Interval
Metric flag. Metric flag.
* 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-syncronization-04 B.1. draft-ietf-xrblock-rtcp-xr-syncronization-05
The following are the major changes compared to previous version:
Editorial changes and typo fixed.
B.2. draft-ietf-xrblock-rtcp-xr-syncronization-04
The following are the major changes compared to previous version: The following are the major changes compared to previous version:
Additional text to clarify on how to distinguish report stream Additional text to clarify on how to distinguish report stream
from reference stream. from reference stream.
Other Editorial changes. Other Editorial changes.
B.2. draft-ietf-xrblock-rtcp-xr-syncronization-03 B.3. draft-ietf-xrblock-rtcp-xr-syncronization-03
The following are the major changes compared to previous version: The following are the major changes compared to previous version:
Remove the need to signal the reference source in the Remove the need to signal the reference source in the
synchronisation offset metrics RTCP XR report. synchronisation offset metrics RTCP XR report.
Apply RFC6390 template to metrics in the appendix. Apply RFC6390 template to metrics in the appendix.
Other editorial changes to get inline with other XRBLOCK drafts. Other editorial changes to get inline with other XRBLOCK drafts.
B.3. draft-ietf-xrblock-rtcp-xr-syncronization-02 B.4. draft-ietf-xrblock-rtcp-xr-syncronization-02
The following are the major changes compared to previous version: The following are the major changes compared to previous version:
Editorial change based on comments raised on the list and in the Editorial change based on comments raised on the list and in the
IETF85 meeting IETF85 meeting
Authors' Addresses Authors' Addresses
Hitoshi Asaeda Hitoshi Asaeda
National Institute of Information and Communications Technology National Institute of Information and Communications Technology
 End of changes. 17 change blocks. 
20 lines changed or deleted 27 lines changed or added

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