Network Working Group A. Clark
Internet-Draft Telchemy
Intended status: Standards Track Q. Wu
Expires: October 13, 2013 Huawei
R. Schott
Deutsche Telekom
G. Zorn
Network Zen
April 11, 2013

RTP Control Protocol (RTCP) Extended Report (XR) Blocks for QoE Metric Reporting
draft-ietf-xrblock-rtcp-xr-qoe-06

Abstract

This document defines an RTP Control Protocol (RTCP) Extended Report (XR) Block including two new segment types and associated SDP parameters that allow the reporting of QoE metrics for use in a range of RTP applications.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at http://datatracker.ietf.org/drafts/current/.

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This Internet-Draft will expire on October 13, 2013.

Copyright Notice

Copyright (c) 2013 IETF Trust and the persons identified as the document authors. All rights reserved.

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Table of Contents

1. Introduction

1.1. QoE Metrics Report Block

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 provides information on multimedia quality using one of several standard metrics.

The metrics belong to the class of application level metrics defined in [RFC6792].

1.2. RTCP and RTCP XR Reports

The use of RTCP for reporting is defined in [RFC3550]. [RFC3611] defined an extensible structure for reporting using an RTCP Extended Report (XR). This draft defines a new Extended Report block for use with [RFC3550] and [RFC3611].

1.3. Performance Metrics Framework

The Performance Metrics Framework [RFC6390] provides guidance on the definition and specification of performance metrics. The RTP Monitoring Architectures [RFC6792] provides guideline for reporting block format using RTCP XR. The XR Block described in this document are in accordance with the guidelines in [RFC6390] and [RFC6792].

1.4. Applicability

The QoE Metrics Report Block can be used in any application of RTP for which QoE measurement algorithms are defined.

The factors that affect real-time AV application quality can be split into two categories. The first category consists of transport- dependent factors such as packet loss, delay and jitter (which also translates into losses in the playback buffer). The factors in the second category are application-specific factors that affect real time application (e.g., video) quality and are sensitivity to network errors. These factors can be but not limited to video codec and loss recovery technique, coding bit rate, packetization scheme, and content characteristics.

Compared with application-specific factors, the transport-dependent factors sometimes are not sufficient to measure real time data quality, since the ability to analyze the real time data in the application layer provides quantifiable measurements for subscriber Quality of Experience (QoE) that may not be captured in the transmission layers or from the RTP layer down. In a typical scenario, monitoring of the transmission layers can produce statistics suggesting that quality is not an issue, such as the fact that network jitter is not excessive. However, problems may occur in the service layers leading to poor subscriber QoE. Therefore monitoring using only network-level measurements may be insufficient when application layer content quality is required.

In order to provide accurate measures of real time application quality when transporting real time contents across a network, the synthentical multimedia quality Metrics is highly required which can be conveyed in the RTCP XR packets[RFC3611] and may have the following three benefits:

2. Terminology

2.1. Standards Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].

The terminology used is

3. QoE Metrics Block

This block reports the multimedia application performance or quality beyond the information carried in the standard RTCP packet format. Information is recorded about multimedia application QoE metric which provides a measure that is indicative of the user's view of a service. Multimedia application QoE metric is commonly expressed as a MOS ("Mean Opinion Score"), MOS is on a scale from 1 to 5, in which 5 represents excellent and 1 represents unacceptable. MOS scores are usually obtained using subjective testing or using objective algorithm. However Subjective testing to estimate the multimedia quality may be not suitable for measuring the multimedia quality since the results may vary from test to test. Therefore using objective algorithm to calculate MOS scores is recommended. ITU-T recommendations define the methodologies for assessment of the performance of multimedia stream [G.107][P.564][G.1082][P.1201.1][P.1201.2][P.1202.1][P.NBAMS-HR] and provides a method to evaluate QoE estimation algorithms and objective model for video and audio. Hence this document recommends vendors and implementers to use these International Telecommunication Union (ITU)-specified methodologies to measure parameters when possible.

3.1. Metric Block Structure

The report block contents are dependent upon a series of flag bits carried in the first part of the header. Not all parameters need to be reported in each block. Flags indicate which are and which are not reported. The fields corresponding to unreported parameters MUST be present, but are set to zero. The receiver MUST ignore any QoE Metrics Block with a non-zero value in any field flagged as unreported. The encoding of QoE metrics block payload consists of a series of 32 bit units called segments that describe MOS Type, MoS algorithm and MoS value.

   
    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     BT=QMB    | I |  Reserved |       Block Length            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        SSRC of source                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Segment  1                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Segment 2                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   ..................
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Segment n                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   

The QoE Metrics Block has the following format:

3.2. Definition of Fields in QoE Metrics Block

Block type (BT): 8 bits


The QoE Metrics Block is identified by the constant <QMB>.

Interval Metric flag (I): 2 bits


This field is used to indicate whether the QoE metrics are Interval or Cumulative metrics, that is, whether the reported values applies to the most recent measurement interval duration between successive metrics reports (I=10) (the Interval Duration) or to the accumulation period characteristic of cumulative measurements (I=11) (the Cumulative Duration) or is a sampled instantaneous value (I=01) (Sampled Value).

Reserved.: 6 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


The length of this report block in 32-bit words, minus one. For the QoE Metrics Block, the block length is variable length.

SSRC of source: 32 bits


As defined in Section 4.1 of [RFC3611].

Segment i: 32 bits


There are two segment types defined in this document: single stream per SSRC segment, multi-channel audio per SSRC segment. Multi-channel audio per SSRC segment is used to deal with the case where Multi-channel audios are carried in one RTP stream while single stream per SSRC segment is used to deal with the case where each media stream is identified by SSRC and sent in separate RTP stream. The leftmost bit of the segment determines its type. If the leftmost bit of the segment is zero, then it is single stream segment. If the leftmost bit is one, then it is multi-channel audio segment. Note that two segment types can not be present in the same metric block.

3.2.1. Single Stream per SSRC Segment

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |S|     CAID      |    PT       |           MOS Value           |     
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Segment Type (S): 1 bit


This field is used to identify the segment type used in this report block. A zero identifies this as a single stream segment. Single stream means there is only one media stream carried in one RTP stream. The single stream segment can be used to report the MoS value associated with the media stream identified by SSRC. If there are multiple media streams and they want to use the single stream per SSRC segment to report the MOS value, they should be carried in the separate RTP streams with each identified by different SSRC. In this case, multiple QoE Metrics Blocks are required to report the MOS value corresponding to each media stream using single stream segment in the same RTCP XR packet.

Calg Algorithm ID (CAID) : 8bits


The 8-bit CAID is the local identifier of calculation algorithm associated with this segment in the range 1-255 inclusive.

Payload Type (PT): 7 bits


QoE metrics reporting depends on the payload format in use. This field identifies the format of the RTP payload. For RTP sessions where multiple payload formats can be negotiated or the payload format changes during the mid-session), the value of this field will be used to indicate what payload format was in use for the reporting interval.

MOS Value: 16 bits


The estimated mean opinion score for multimedia application quality is defined as including the effects of delay,loss, discard,jitter and other effects that would affect multimedia quality . It is expressed in numeric format 8:8 with the value in the range 0.0 to 255.996. The valid the measured value ranges from 0.0 to 50.0, corresponding to MoS x 10 as for MoS. If the measured value is over ranged, the value 0xFFFE MUST be reported to indicate an over-range measurement. If the measurement is unavailable, the value 0xFFFF MUST be reported. Values other than 0xFFFE,0xFFFF and the valid range defined above MUST NOT be sent and MUST be ignored by the receiving system.

3.2.2. Multi-Channel audio per SSRC Segment

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |S|     CAID      |    PT       |CHID |        MOS Value        |     
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Segement Type (S): 1 bit


This field is used to identify the segment type used in this report block. A one identifies this as a multi-channel audio segment.

CAlg Algorithm ID (CAID) : 8bits


The 8-bit ID is the local identifier of this segment in the range 1-255 inclusive.

Payload Type (PT): 7 bits


As defined in Section 3.2.1 of this document.

Channel Identifier (CHID): 3 bits


If multiple channels of audio are carried in one RTP stream, each channel of audio will be viewed as a independent channel(e.g., left channel audio, right channel audio). This field is used to identify each channel carried in the same media stream. The default Channel mapping follows static ordering rule described in the section 4.1 of [RFC3551]. However there are some payload formats that use different channel mappings, e.g., AC-3 audio over RTP [RFC4184] only follow AC-3 channel order scheme defined in [ATSC]. Enhanced AC-3 Audio over RTP [RFC4598] uses dynamic channel transform mechanism. In order that the appropriate channel mapping can be determined, QoE reports need to be tied to an RTP payload format, i.e., including the payload type of the reported media according to [RFC6792] and using Payload Type to determine the appropriate channel mapping.

MOS Value: 13 bits


The estimated mean opinion score for multimedia application quality is defined as including the effects of delay,loss, discard,jitter and other effects that would affect multimedia quality . It is expressed in numeric format 6:7 with the value in the range 0.0 to 63.992. The valid the measured value ranges from 0.0 to 50.0, corresponding to MoS x 10 as for MoS. If the measured value is over ranged, the value 0x1FFE MUST be reported to indicate an over-range measurement. If the measurement is unavailable, the value 0x1FFF MUST be reported. Values other than 0x1FFE,0x1FFF and the valid range defined above MUST NOT be sent and MUST be ignored by the receiving system.

4. SDP Signaling

[RFC3611] defines the use of SDP (Session Description Protocol) [RFC4566] for signaling the use of XR blocks. However XR blocks MAY be used without prior signaling (see section 5 of RFC3611).

4.1. SDP rtcp-xr-attrib Attribute Extension

This section augments the SDP [RFC4566] attribute "rtcp-xr" defined in [RFC3611] by providing an additional value of "xr-format" to signal the use of the report block defined in this document. Within the "xr-format", the syntax element "extmap" is an attribute as defined in [RFC4566] and used to signal the mapping of the local identifier (CAID) in the segment extension defined in section 3.2 to the calculation algorithm. Specific extensionattributes are defined by the specification that defines a specific extension name; there may be several.

xr-format =/ xr-qoe-block
xr-qoe-block = "qoe-metrics" ["=" extmap *("," extmap)]
extmap =  mapentry "=" extensionname [SP extentionattributes]
direction = "sendonly" / "recvonly" / "sendrecv" / "inactive"
mapentry =  "calg:" 1*5 DIGIT ["/" direction]
extensionname = "P564";ITU-T P.564 Compliant Algorithm [P.564]
              / "G107";ITU-T G.107 [G.107]
              / "TS101_329";ETSI TS 101 329-5 Annex E [ ETSI]
              /"JJ201_01 ";TTC JJ201.01 [TTC]
              /"P1201_01";ITU-T P.1201.2 [P.1201.1]
              /"P1201_02";ITU-T P.1201.2 [P.1201.2]
              /"P1202_01";ITU-T P.1202.1 [P.1202.1]
              /"P1202_02";ITU-T P. NBAMS-HR [P.NBAMS-HR]
              / non-ws-string
extentionattributes = mediatype 
                    /mosreference
                    /attributes-ext
mediatype = "a" ;voice
          / "v" ;video
          /"m" ;multimedia
mosreference =  "mosref=" ("0"; lower resolution
                          / "1";higher resolution
                          / 1*2DIGIT ) ;Value 2~15 are valid and
                                       ;reserved for future use
attributes-ext = non-ws-string
SP = <Define in RFC5234>
DIGIT = <as defined in Section 3.4 of [RFC5234]>
non-ws-string  = 1*(%x21-FF)

a=extmap:<value> ["/"<direction>] <name> <extensionattributes>

Each local identifier (CAID)of calculation algorithm used in the segment defined in the section 3.2 is mapped to a string using an attribute of the form:

Example:
a = calg:1=G107,calg:2=P1202.1

where <name> is a calculation algorithm name, as above, <value> is the local identifier (CAID)of the calculation algorithm associated with the segment defined in this document and is an integer in the valid range inclusive.

A usable mapping MUST use IDs in the valid range, and each ID in this range MUST be unique and used only once for each stream or each channel in the stream.

The mapping MUST be provided per media stream (in the media-level section(s) of SDP, i.e., after an "m=" line).

Note that the syntax element "mosreference" is referred to the media resolution(e.g., Narrowband (3.4kHz) Speech and Standard Definition (SD) Resolution Video with lower resolution, Wideband (7kHz) Speech and High Definition (HD) Resolution Video with higher resolution). MOS scores reported in the QoE block may vary with the Mos reference; For example MOS values for narrowband, wideband codecs occupy the same range but should be reported in different value. For video application,MoS scores for SD resolution, HD resolution video also occupy the same ranges and should be reported in different value.

4.2. Offer/Answer Usage

When SDP is used in offer-answer context, the SDP Offer/Answer usage defined in [RFC3611] applies. In the offer answer context, the signaling described above may be used in three ways:

A direction attribute MAY be included in an extmap; without it, the direction implicitly inherits, of course, from the stream direction.

Segment extension, with their directions, may be signaled for an "inactive" stream. It is an error to use an extension direction incompatible with the stream direction (e.g., a "sendonly" attribute for a "recvonly" stream).

If an segment extension map is offered as "sendrecv", explicitly or implicitly, and asymmetric behavior is desired, the SDP may be modified to modify or add direction qualifiers for that segment extension.

Local identifiers in the valid range inclusive in an offer or answer must not be used more than once per media section. A session update MAY change the direction qualifiers of segment extensions under use. A session update MAY add or remove segment extension(s). Identifiers values in the valid range MUST NOT be altered (remapped).

If a party wishes to offer mutually exclusive alternatives, then multiple segment extensions with the same identifier in the (unusable) range 4096-4351 may be offered; the answerer should select at most one of the offered extensions with the same identifier, and remap it to a free identifier in the valid range, for that extension to be usable. Note that two segment types defined in section 3 are also two exclusive alternatives.

If more segment extensions are offered in the valid range, the answerer should choose those that are desired, and place the offered identifier value "as is" in the SDP answer.

Similarly, if more segment extensions are offered than can be fit in the valid range, identifiers in the range 4096-4351 may be offered; the answerer should choose those that are desired, and remap them to a free identifier in the valid range.

Example (port numbers, RTP profiles, payload IDs and rtpmaps, etc.
all omitted for brevity):

The offer:

Note that the range 4096-4351 for these negotiation identifiers is deliberately restricted to allow expansion of the range of valid identifiers in future. segment extensions with an identifier outside the valid range cannot, of course, be used.

The answerer is interested in transmission P.1202.1 only on video, but doesn't understand P.1202.1 at all. It is interested in transmission G.107 on audio. It therefore adjusts the declarations:

a=rtcp-xr:qoe-metrics=calg:1=P1202.1v, calg:2=G107a

5. IANA Considerations

New block types for RTCP XR are subject to IANA registration. For general guidelines on IANA considerations for RTCP XR, refer to [RFC3611].

5.1. New RTCP XR Block Type value

This document assigns the block type value MMQ in the IANA "RTCP XR Block Type Registry" to the "QoE Metrics Block".

[Note to RFC Editor: please replace MMQ with the IANA provided RTCP XR block type for this block.]

5.2. New RTCP XR SDP Parameter

This document also registers a new parameter "qoe-metrics" in the "RTCP XR SDP Parameters Registry".

5.3. Contact information for registrations

Qin Wu
sunseawq@huawei.com
101 Software Avenue, Yuhua District 
Nanjing, JiangSu 210012 China

The contact information for the registrations is:

5.4. New registry of calculation algorithms

Name             Name Description                  Reference    Type
=========   ===================================   ==========    ====
P564       ITU-T P.564 Compliant Algorithm        [P.564]        Voice
G107       ITU-T G.107                            [G.107]        Voice
TS101_329  ETSI TS 101 329-5 Annex E              [ETSI]         Voice
JJ201_01   TTC JJ201.01                           [TTC]          Voice
P1201_01   ITU-T P.1201.01                    [P.1201.1]      Multimedia
P1201_02   ITU-T P.1201.02                    [P.1201.2]      Multimedia
P1202_01   ITU-T P.1202.01                   [P.1202.01]         Video
P1202_02   ITU-T P. NBAMS-HR               [P. NBAMS-HR]         Video

This document creates a new registry to be called "RTCP XR QoE metric block - multimedia application Calculation Algorithm" as a sub- registry of the "RTP Control Protocol Extended Reports (RTCP XR) Block Type Registry". This registry applies to the multimedia session where each type of media are sent in a separate RTP stream and also applies to the session where Multi-channel audios are carried in one RTP stream. Policies for this new registry are as follows:

6. Security Considerations

The new RTCP XR report blocks proposed in this document introduces no new security considerations beyond those described in [RFC3611].

7. Authors

This draft merges ideas from two drafts addressing the QoE metric Reporting issue. The authors of these drafts are listed below (in alphabetical order):

8. Acknowledgements

The authors gratefully acknowledge the comments and contributions made by Bruce Adams, Philip Arden, Amit Arora, Bob Biskner, Kevin Connor, Claus Dahm, Randy Ethier, Roni Even, Jim Frauenthal, Albert Higashi, Tom Hock, Shane Holthaus, Paul Jones, Rajesh Kumar, Keith Lantz, Mohamed Mostafa, Amy Pendleton, Colin Perkins, Mike Ramalho, Ravi Raviraj, Albrecht Schwarz, Tom Taylor, Bill Ver Steeg, David R Oran, Ali Begen and Hideaki Yamada.

9. References

9.1. Normative References

[RFC3611] Friedman, T., Caceres, R. and A. Clark, "RTP Control Protocol Extended Reports (RTCP XR)", RFC 3611, November 2003.
[RFC3550] Schulzrinne, H., "RTP: A Transport Protocol for Real-Time Applications", RFC 3550, July 2003.
[RFC3551] Schulzrinne, H. and S. Casner, "RTP Profile for Audio and Video Conferences with Minimal Control", RFC 3551, July 2003.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4566] Handley, M., Jacobson, V. and C. Perkins, "SDP: Session Description Protocol", RFC 4566, July 2006.
[RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", STD 68, RFC 5234, January 2008.
[RFC5226] Narten, T., "Guidelines for Writing an IANA Considerations Section in RFCs", RFC 5226, May 2008.
[ATSC] U.S. Advanced Television Systems Committee (ATSC), "ATSC Standard: Digital Audio Compression (AC-3), Revision B", ATSC Doc A/52B, June 2005.

9.2. Informative References

[G.1082] ITU-T, "Measurement-based methods for improving the robustness of IPTV performance", ITU-T Recommendation G.1082, April 2009.
[P.564] ITU-T, "Conformance testing for narrowband Voice over IP transmission quality assessment models", ITU-T Recommendation P.564, July 2006.
[G.107] ITU-T, "The E Model, a computational model for use in transmission planning", ITU-T Recommendation G.107, April 2009.
[ETSI] ETSI, "Quality of Service (QoS) measurement methodologies", ETSI TS 101 329-5 V1.1.1, November 2000.
[P.1201.1] ITU-T, "Parametric non-intrusive assessment of audiovisual media streaming quality - lower resolution application area", ITU-T Recommendation P.1201.1, October 2012.
[P.1201.2] ITU-T, "Parametric non-intrusive assessment of audiovisual media streaming quality - higher resolution application area", ITU-T Recommendation P.1201.2, October 2012.
[P.1202.1] ITU-T, "Parametric non-intrusive bitstream assessment of video media streaming quality - lower resolution application area", ITU-T Recommendation P.1202.1, October 2012.
[P.NBAMS-HR] ITU-T, "Parametric non-intrusive bitstream assessment of video media streaming quality - higher resolution application area", ITU-T Recommendation P.NBAMS-HR, October 2012.
[RFC6792] Wu, Q., "Monitoring Architectures for RTP", RFC 6792, November 2012.
[TTC] TTC 201.01 (Japan), "A method for speech quality assessment for Voice over IP", .
[RFC6390] Clark, A. and B. Claise, "Framework for Performance Metric Development", RFC 6390, October 2011.
[RFC4598] Link, B., "Real-time Transport Protocol (RTP) Payload Format for Enhanced AC-3 (E-AC-3) Audio", RFC 4598, July 2006.
[RFC4184] Link, B., Hager, T. and J. Flaks, "RTP Payload Format for AC-3 Audio", RFC 4184, October 2005.

Appendix A. Evaluation Example of User Quality of Experience for video stream

To evaluate user quality of experience levels using objective test data. MoS Scores provide a familiar, easily understood numeric representation of video, audio, and overall audiovisual quality. Unlike audio, video is even more sensitive to transport impairments than voice, and even low rates of packet loss can cause severe degradation in perceived quality. However, all occurrences of packet loss do not have an equal impact on perceptual quality, in part because of the way video frames are structured during the encoding process – such as frame properties including frame type and quantization parameter (QP), frame structure, and in part due to subjective factors – such as the degree to which perception is affected by the levels of motion and detail in the video sequence, demux/decoder statistics characteristic parameters including packet loss concealment metrics,jitter buffer metrics and/or Frame loss rate parameter. Note that Frame loss rate can be derived When a video stream is sent from the media source to RTP receiving end and get monitored, in order to provide accurate evaluation of video quality, One possible evaluation method of QoE is the network nodes that implement network management tools may get frame properties,perception degree as MoS calculation input parameters from media source, and demux/decoder statistics characteristic parameters and transport impairment as other MoS calculation input parameters from the RTP receiving end and use appropriate MoS calculation algorithm to calculate MoS scores. Such MoS Scores value can be useful for troubleshooting or comparing video quality across different service types.

Appendix B. Change Log

B.1. draft-ietf-xrblock-rtcp-xr-qoe-06

The following are the major changes compared to previous two versions:

B.2. draft-ietf-xrblock-rtcp-xr-qoe-04

The following are the major changes compared to previous version:

B.3. draft-ietf-xrblock-rtcp-xr-qoe-03

The following are the major changes compared to previous version:

B.4. draft-ietf-xrblock-rtcp-xr-qoe-02

The following are the major changes compared to previous version:

B.5. draft-ietf-xrblock-rtcp-xr-qoe-01

The following are the major changes compared to previous version:

B.6. draft-ietf-xrblock-rtcp-xr-qoe-00

The following are the major changes compared to previous version:

Authors' Addresses

Alan Clark Telchemy Incorporated 2905 Premiere Parkway, Suite 280 Duluth, GA 30097 USA EMail: alan.d.clark@telchemy.com
Qin Wu Huawei 101 Software Avenue, Yuhua District Nanjing, Jiangsu 210012 China EMail: sunseawq@huawei.com
Roland Schott Deutsche Telekom Heinrich-Hertz-Straße 3-7 Darmstadt, 64295 Germany EMail: Roland.Schott@telekom.de
Glen Zorn Network Zen 77/440 Soi Phoomjit, Rama IV Road Phra Khanong, Khlong Toie Bangkok, 10110 Thailand Phone: +66 (0) 87 502 4274 EMail: gwz@net-zen.net