draft-ietf-xrblock-rtcp-xr-synchronization-00.txt   draft-ietf-xrblock-rtcp-xr-synchronization-01.txt 
Network Working Group H. Asaeda Network Working Group H. Asaeda
Internet-Draft Keio University Internet-Draft NICT
Intended status: Standards Track R. Huang Intended status: Standards Track R. Huang
Expires: January 31, 2013 Q. Wu Expires: April 21, 2013 Q. Wu
Huawei Huawei
July 30, 2012 October 18, 2012
RTCP XR Blocks for Synchronization Delay and Offset Metrics Reporting RTP Control Protocol (RTCP) Extended Report (XR) Blocks for
draft-ietf-xrblock-rtcp-xr-synchronization-00 Synchronization Delay and Offset Metrics Reporting
draft-ietf-xrblock-rtcp-xr-synchronization-01
Abstract Abstract
This document defines two RTCP XR Report Blocks and associated with This document defines two RTP Control Protocol (RTCP) Extended Report
SDP parameters that allow the reporting of synchronization delay and (XR) Blocks and associated with SDP parameters that allow the
offset metrics for use in a range of RTP applications. reporting of synchronization delay and 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
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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 January 31, 2013. This Internet-Draft will expire on April 21, 2013.
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.
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
skipping to change at page 2, line 18 skipping to change at page 2, line 20
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Standards Language . . . . . . . . . . . . . . . . . . . . 3 2.1. Standards Language . . . . . . . . . . . . . . . . . . . . 3
3. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 4
4. RTP Flows Initial Synchronization Delay Report Block . . . . . 4 4. RTP Flows Initial Synchronization Delay Report Block . . . . . 4
4.1. Metric Block Structure . . . . . . . . . . . . . . . . . . 5 4.1. Metric Block Structure . . . . . . . . . . . . . . . . . . 5
4.2. Definition of Fields in RTP Flow Initial 4.2. Definition of Fields in RTP Flow Initial
Synchronization Delay Metrics Block . . . . . . . . . . . 5 Synchronization Delay Metrics Block . . . . . . . . . . . 5
5. RTP Flows Synchronization Offset Metrics Block . . . . . . . . 6 5. RTP Flows Synchronization Offset Metrics Block . . . . . . . . 6
5.1. Metric Block Structure . . . . . . . . . . . . . . . . . . 6 5.1. Metric Block Structure . . . . . . . . . . . . . . . . . . 6
5.2. Definition of Fields in RTP Flow General 5.2. Definition of Fields in RTP Flow General
Synchronization Offset Metrics Block . . . . . . . . . . . 6 Synchronization Offset Metrics Block . . . . . . . . . . . 7
6. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 7 6. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 8
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 6.1. SDP rtcp-xr-attrib Attribute Extension . . . . . . . . . . 8
8. Security Considerations . . . . . . . . . . . . . . . . . . . 8 6.2. Offer/Answer Usage . . . . . . . . . . . . . . . . . . . . 8
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
8. Security Considerations . . . . . . . . . . . . . . . . . . . 9
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9
10.1. Normative References . . . . . . . . . . . . . . . . . . . 9 10.1. Normative References . . . . . . . . . . . . . . . . . . . 9
10.2. Informative References . . . . . . . . . . . . . . . . . . 9 10.2. Informative References . . . . . . . . . . . . . . . . . . 10
Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 9 Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 10
A.1. draft-asaeda-xrblock-rtcp-xr-syncronization-07 . . . . . . 9 A.1. draft-ietf-xrblock-rtcp-xr-syncronization-01 . . . . . . . 10
A.2. draft-asaeda-xrblock-rtcp-xr-syncronization-06 . . . . . . 10
A.3. draft-asaeda-xrblock-rtcp-xr-syncronization-05 . . . . . . 10
A.4. draft-asaeda-xrblock-rtcp-xr-syncronization-04 . . . . . . 10
A.5. draft-asaeda-xrblock-rtcp-xr-syncronization-03 . . . . . . 10
A.6. draft-asaeda-xrblock-rtcp-xr-syncronization-02 . . . . . . 10
A.7. draft-asaeda-xrblock-rtcp-xr-syncronization-01 . . . . . . 10
A.8. draft-asaeda-xrblock-rtcp-xr-syncronization-00 . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction 1. Introduction
This draft defines two new block types to augment those defined in This draft 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
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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
audio and video streams), with the same RTCP CNAME included in RTCP audio and video streams), with the same RTCP CNAME included in RTCP
SDES packets [RFC3550]. Information is recorded about the SDES packets [RFC3550]. Information is recorded about the
synchronization offset time of each RTP stream relative to the synchronization offset time of each RTP stream relative to the
reference RTP stream with the same CNAME and General Synchronization reference RTP stream with the same CNAME and General Synchronization
Offset of zero. Offset of zero.
These metrics belong to the class of terminal related transport level These metrics belong to the class of transport level metrics defined
metrics defined in [MONARCH]. in [MONARCH].
2. Terminology 2. Terminology
2.1. Standards Language 2.1. Standards Language
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:
Initial Synchronization Delay: Initial Synchronization Delay:
A multimedia session comprises a set of concurrent RTP sessions A multimedia session comprises a set of concurrent RTP sessions
among a common group of participants, using one RTP session for among a common group of participants, using one RTP session for
each media type. Initial synchronization Delay is the average each media type. The initial synchronization Delay is the average
time for receiver to synchronize the components of a multimedia time for receiver to synchronize all components of a multimedia
session [RFC6051]. session [RFC6051].
Synchronization Offset: Synchronization Offset:
The absolute delay variance of the measured RTP stream relative to Synchronization between two media streams must be maintained to
the reference RTP stream in the multimedia session. ensure satisfactory QoE. Two media streams can be of the same
media type belonging to one RTP session or in different media
types belonging to one multimedia session. The Synchronization
Offset is the relative time difference of the two media streams
that need to be synchronized.
3. Applicability 3. Applicability
The report blocks defined in this document could be used by dedicated The report blocks defined in this document could be used by dedicated
network monitoring applications. network monitoring applications.
When joining each session in layered video sessions [RFC6190] or the When joining each session in layered video sessions [RFC6190] or the
multimedia session, a receiver may not synchronize playout across the multimedia session, a receiver may not synchronize playout across the
multimedia session or layered video session until RTCP SR packets multimedia session or layered video session until RTCP SR packets
have been received on all of the component RTP sessions. The have been received on all components of RTP sessions. The component
component RTP session are referred to as each RTP session for each RTP session are referred to as each RTP session for each media type
media type in multimedia session or separate RTP session for each in multimedia session or separate RTP session for each layer in the
layer in the layered video session. For unicast session, the delay layered video session. For unicast session, the delay due to
due to negotiation of NAT pinholes, firewall holes, quality-of- negotiation of NAT pinholes, firewall holes, quality-of-service, and
service, and media security keys is contributed to such initial media security keys is contributed to such initial synchronization
synchronization playout. For multicast session, such initial playout. For multicast session, such initial synchronization delay
synchronization delay varies with the session bandwidth, the number varies with the session bandwidth, the number of members, and the
of members, and the number of senders in the session. The RTP flow number of senders in the session. The RTP flow Initial
Initial synchronization delay block can be used to report the initial synchronization delay block can be used to report the initial
synchronization delay to receive all the RTP streams belonging to the synchronization delay to receive all the RTP streams belonging to the
same multimedia session or layered video session. In the absence of same multimedia session or layered video session. In the absence of
packet loss, the initial synchronization delay equals to the average packet loss, the initial synchronization delay equals to the average
time taken to receive the first RTCP packet in the RTP session with time taken to receive the first RTCP packet in the RTP session with
the longest RTCP reporting interval. In the presence of packet loss, the longest RTCP reporting interval. In the presence of packet loss,
the media synchronization needs to based on the in-band mapping of the media synchronization needs to based on the in-band mapping of
RTP and NTP-format timestamps [RFC6051] or wait until the reporting RTP and NTP-format timestamps [RFC6051] or wait until the reporting
interval has passed, and the next RTCP SR packet is sent. interval has passed, and the next RTCP SR packet is sent.
In an RTP multimedia session, there can be an arbitrary number of In an RTP multimedia session, there can be an arbitrary number of
streams carried in different RTP sessions, with the same RTCP CNAME. streams carried in different RTP sessions, with the same RTCP CNAME.
These streams may be not synchronized with each other. For example, These streams may be not synchronized with each other. For example,
one audio stream and one video stream belong to the same session and one audio stream and one video stream belong to the same session and
audio stream are transmitted lag behind video stream for multiple audio stream are transmitted lag behind video stream for multiple
tens of milliseconds. The RTP Flows Synchronization Offset block can tens of milliseconds [TR-126]. The RTP Flows Synchronization Offset
be used to report such synchronization offset between video stream block can be used to report such synchronization offset between video
and audio stream. stream and audio stream.
4. RTP Flows Initial Synchronization Delay Report Block 4. RTP Flows Initial Synchronization Delay Report Block
This block is sent by RTP receivers and reports Initial This block is sent by RTP receivers and reports Initial
synchronization delay beyond the information carried in the standard synchronization delay beyond the information carried in the standard
RTCP packet format. Information is recorded about time difference RTCP packet format. Information is recorded about time difference
between the start of RTP sessions and the time the RTP receiver between the start of RTP sessions and the time the RTP receiver
acquires all components of RTP sessions [RFC6051]. acquires all components of RTP sessions [RFC6051].
4.1. Metric Block Structure 4.1. Metric Block Structure
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| SSRC of Source | | SSRC of Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Initial Synchronization Delay | | Initial Synchronization Delay |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4.2. Definition of Fields in RTP Flow Initial Synchronization Delay 4.2. Definition of Fields in RTP Flow Initial Synchronization Delay
Metrics Block Metrics Block
Block type (BT): 8 bits Block type (BT): 8 bits
The Statistics Summary Report Block is identified by the constant The RTP Flows Initial Synchronization Delay Report Block is
<RFISD>. identified by the constant <RFISD>.
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 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 an arbitrary RTP stream belonging to the identifier carried in any arbitrary component of RTP sessions
same multimedia session. belonging to the same multimedia session.
Initial Synchronization Delay: 32 bits Initial Synchronization Delay: 32 bits
The average delay, expressed in units of 1/65536 seconds, from the The average delay, expressed in units of 1/65536 seconds, from the
RTCP packets received on all of the components RTP sessions to the RTCP packets received on all of the components RTP sessions to the
beginning of session [RFC6051]. The value is calculated based on beginning of session [RFC6051]. The value is calculated based on
the information contained in RTCP SR packets or the in-band received RTCP SR packets or the RTP header extension containing
mapping of RTP and NTP-format timestamps [RFC6051]. If there is in-band mapping of RTP and NTP-format timestamps [RFC6051]. If
no packet loss, the initial synchronization delay is expected to there is no packet loss, the initial synchronization delay is
be equal to the average time taken to receive the first RTCP expected to be equal to the average time taken to receive the
packet in the RTP session with the longest RTCP reporting first RTCP packet in the RTP session with the longest RTCP
interval. reporting interval or the average time taken to receive the first
RTP header extension containing in-band mapping 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 SHOULD be reported. all bits set to 1 SHOULD be reported.
5. RTP Flows Synchronization Offset Metrics Block 5. RTP Flows Synchronization Offset Metrics Block
In the RTP multimedia sessions, there can be an arbitrary number of In the RTP multimedia sessions, there can be an arbitrary number of
streams and each stream (e.g., audio stream or video stream) is sent Media streams and each media stream (e.g., audio stream or video
in a separate RTP stream. The receiver associates RTP streams to be stream) is sent in a separate RTP stream. The receiver associates
synchronized by means of RTCP CNAME contained in the RTCP Source RTP streams to be synchronized by means of RTCP CNAME contained in
Description (SDES) packets [RFC3550]. the RTCP Source Description (SDES) packets [RFC3550].
This block is sent by RTP receivers and reports synchronization This block is sent by RTP receivers and reports synchronization
offset of the arbitrary two RTP streams that needs to be synchronized offset of the arbitrary two RTP streams that needs to be synchronized
in the RTP multimedia session. Information is recorded about the in the RTP multimedia session. Information is recorded about the
actual delay variance of the measured RTP stream relative to he relative time difference between two media streams with the same
reference RTP stream with the same CNAME. The reference RTP stream CNAME. In two media streams, one media stream is the reference
can be chosen as the arbitrary stream with minimum delay according to stream, which can be chosen as the arbitrary stream with minimum
the common criterion defined in section 6.2.2.1 of [Y.1540]. delay according to the common criterion defined in section 6.2.2.1 of
[Y.1540].
5.1. Metric Block Structure 5.1. 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 | Reserved | Block length=3 | | BT=RFSO |L| Reserved | Block length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of source | | SSRC of source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of reference |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Synchronization Offset, most significant word | | Synchronization Offset, most significant word |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Synchronization Offset, least significant word | | Synchronization Offset, least significant word |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
5.2. Definition of Fields in RTP Flow General Synchronization Offset 5.2. Definition of Fields in RTP Flow General Synchronization Offset
Metrics Block Metrics Block
Block type (BT): 8 bits Block type (BT): 8 bits
The RTP Flow General Synchronization Offset Report Block is The RTP Flow General Synchronization Offset Report Block is
identified by the constant <RFSO>. identified by the constant <RFSO>.
Lag and Lead Indication (L): 1 bit
This field is used to indicate whether the reporting stream lead
before the reference stream or lag behind the reference stream.
The value of this field is set to 1, if the reporting stream lead
before the reference stream, 0 otherwise.
Reserved: 7 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 Block length: 16 bits
The constant 3, in accordance with the definition of this field in The constant 4, 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 of the reference RTP stream to which the XR relates. identifier of the reporting RTP stream to which the XR relates.
SSRC of Reference: 32 bits
The SSRC of the reference stream SHALL be set to the value of the
SSRC identifier of the reference RTP stream to which the XR
relates.
Synchronization Offset: 64 bits Synchronization Offset: 64 bits
The synchronization offset of one RTP stream relative to the The synchronization offset of the reporting RTP stream relative to
reference RTP stream with the same CNAME. The Synchronization the reference RTP stream with the same CNAME. The calculation of
Offset of the reference stream should be zero. This value is Synchronization Offset is similar to Difference D calculation in
calculated based on the interarrival time between an arbitrary RTP the RFC3550. That is to say,if Si is the RTP timestamp from the
packet and the reference RTP packet with the same CNAME, and reporting RTP packet i, and Ri is the time of arrival in RTP
timestamps of this arbitrary RTP packet and the reference RTP timestamp units for reporting RTP packet i, Sj is the RTP
packet with the same CNAME. The value of this field is timestamp from the reference RTP packet j, and Rj is the time of
represented using a 64-bit NTP-format timestamp as defined in arrival in RTP timestamp units for reference RTP packet j, then
[RFC5905], which is 64-bit unsigned fixed-point number with the the value of the synchronization offset D may be expressed as
integer part in the first 32 bits and the fractional part in the D(i,j) = (Rj - Ri) - (Sj - Si) = (Rj - Sj) - (Ri - Si)
last 32 bits. The value of the synchronization offset is represented using a 64-
bit NTP-format timestamp as defined in [RFC5905], which is 64-bit
unsigned fixed-point number with the integer part in the first 32
bits and the fractional part in the last 32 bits.
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 SHOULD be reported. all bits set to 1 SHOULD be reported.
6. SDP Signaling 6. SDP Signaling
[RFC3611] defines the use of SDP (Session Description Protocol)
[RFC4566] for signaling the use of XR blocks. XR blocks MAY be used
without prior signaling.
6.1. SDP rtcp-xr-attrib Attribute Extension
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]:
rtcp-xr-attrib = "a=rtcp-xr:" rtcp-xr-attrib = "a=rtcp-xr:"
[xr-format *(SP xr-format)] CRLF [xr-format *(SP xr-format)] CRLF
xr-format = RTP-flows-init-syn-delay
/ RTP-flows-syn-offset xr-format = RTP-flows-init-syn-delay
RTP-flows-init-syn-delay = "RTP-flows-init-syn-delay" / RTP-flows-syn-offset
["=" max-size]
RTP-flow-syn-offset = "RTP-flows-syn-offset" RTP-flows-init-syn-delay = "RTP-flows-init-syn-delay"
["=" max-size] RTP-flow-syn-offset = "RTP-flows-syn-offset"
max-size = 1*DIGIT ; maximum block size in octets
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.
6.2. Offer/Answer Usage
When SDP is used in offer-answer context, the SDP Offer/Answer usage
defined in [RFC3611] applies.
7. IANA Considerations 7. IANA Considerations
New report block types for RTCP XR are subject to IANA registration. New report block types for RTCP XR are subject to IANA registration.
For general guidelines on IANA allocations for RTCP XR, refer to For general guidelines on IANA allocations for RTCP XR, refer to
Section 6.2 of [RFC3611]. Section 6.2 of [RFC3611].
This document assigns two new block type values in the RTCP XR Block This document assigns two new block type values in the RTCP XR Block
Type Registry: Type Registry:
Name: RFISD Name: RFISD
Long Name: RTP Flows Initial Synchronization Delay Long Name: RTP Flows Initial Synchronization Delay
Value <RFISD> Value <RFISD>
Reference: Section 4 Reference: Section 4
skipping to change at page 9, line 34 skipping to change at page 10, line 30
Time Protocol Version 4: Protocol and Algorithms Time Protocol Version 4: Protocol and Algorithms
Specification", RFC 5905, June 2010. Specification", RFC 5905, June 2010.
[RFC6051] Perkins, C. and T. Schierl, "Rapid Synchronisation of RTP [RFC6051] Perkins, C. and T. Schierl, "Rapid Synchronisation of RTP
Flows", RFC 6051, November 2010. Flows", RFC 6051, November 2010.
[RFC6190] Wenger, S., Wang, Y., Schierl, T., and A. Eleftheriadis, [RFC6190] Wenger, S., Wang, Y., Schierl, T., and A. Eleftheriadis,
"RTP Payload Format for Scalable Video Coding", RFC 6190, "RTP Payload Format for Scalable Video Coding", RFC 6190,
May 2011. May 2011.
[TR-126] BBF Forum, "Triple-play Services Quality of Experience
(QoE) Requirements", December 2006.
10.2. Informative References 10.2. Informative References
[MONARCH] Wu, Q., "Monitoring Architectures for RTP", [MONARCH] Wu, Q., "Monitoring Architectures for RTP",
ID draft-ietf-avtcore-monarch-13, May 2012. ID draft-ietf-avtcore-monarch-22, September 2012.
[Y.1540] ITU-T, "ITU-T Rec. Y.1540, IP packet transfer and [Y.1540] ITU-T, "ITU-T Rec. Y.1540, IP packet transfer and
availability performance parameters", November 2007. availability performance parameters", November 2007.
Appendix A. Change Log Appendix A. 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.
A.1. draft-asaeda-xrblock-rtcp-xr-syncronization-07 A.1. draft-ietf-xrblock-rtcp-xr-syncronization-01
Editorial changes are made from the previous version 06.
A.2. draft-asaeda-xrblock-rtcp-xr-syncronization-06
The following are the major changes compared to previous version 05:
o Define synchronization offset as 64 bit NTP-format timestamp to
meet synchronization resolution requirements for some RTP
applications.
o Add the definition of Initial Synchronization Delay in section 2.
o Other editorial changes.
A.3. draft-asaeda-xrblock-rtcp-xr-syncronization-05
The following are the major changes compared to previous version 04:
o Remove per packet reporting and only report a single value of
general synchronization offset.
A.4. draft-asaeda-xrblock-rtcp-xr-syncronization-04
The following are the major changes compared to previous version 03:
o Add a definition for synchronization offset.
o Use additional text in applicability section to clarify the
difference between synchronization delay and offset.
o Add a reference to tell how to select the reference stream.
o Other Editorial Changes.
A.5. draft-asaeda-xrblock-rtcp-xr-syncronization-03
The following are the major changes compared to previous version 02:
o Support multiple general synchronization offset reporting.
o Other Editorial Changes.
A.6. draft-asaeda-xrblock-rtcp-xr-syncronization-02
The following are the major changes compared to previous version 01:
o Clarify which synchronization is reported in section 4 and 5.
o Allow calculating the synchronization delay based on RTP header
extension defined in RFC6051
o Explain what the components of RTP session are in section 3.
A.7. draft-asaeda-xrblock-rtcp-xr-syncronization-01
The following are the major changes compared to previous version:
o Separate Synchronization Delay and Offset Metrics Block into two
independent block based on comments on the list.
A.8. draft-asaeda-xrblock-rtcp-xr-syncronization-00
The following are the major changes compared to previous version: The following are the major changes compared to previous version:
This document is separated from Editorial change based on comments raised on the list.
draft-wu-xrblock-rtcp-xr-quality-monitoring-01 with some editorial
changes and focuses on RTP Flow Initial Synchronization Delay and
RTP Flows General Synchronization Offset.
Authors' Addresses Authors' Addresses
Hitoshi Asaeda Hitoshi Asaeda
Keio University National Institute of Information and Communications Technology
Graduate School of Media and Governance 4-2-1 Nukui-Kitamachi
5322 Endo Koganei, Tokyo 184-8795
Fujisawa, Kanagawa 252-0882
Japan Japan
Email: asaeda@wide.ad.jp Email: asaeda@nict.go.jp
Rachel Huang Rachel Huang
Huawei Technologies Co., Ltd. Huawei Technologies Co., Ltd.
101 Software Avenue, Yuhua District 101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012 Nanjing, Jiangsu 210012
China China
Email: Rachel@huawei.com Email: Rachel@huawei.com
Qin Wu Qin Wu
 End of changes. 35 change blocks. 
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