Quality of service for the user (parameters, models, measurement) and interoperability issues

1. Quality of service for the user (parameters, models, measurement) and interoperability issues Jean-Yves Monfort ITU-T SG 12 Chairman France Telecom, R&D Division

2. General messages on QoS and Interoperability from the CTO's meeting organized by TSB Director (Dec 2003) , applicable to Home networking and Home services http://www.itu.int/ITU-T/tsb-director/cto/index.html - ITU-T should ensure global interoperability (Interoperability for all major services required on a global scale and interoperability for the required core middleware functionalities). - Mechanisms to provide end-to-end QoS are required (including session based QoS, QoS Classes or High quality classes,…) - Simplicity and ease of use for the end users , QoS determined by user choice of service, and high quality for voice (e.g. wideband) 2020-01-05 2

3. Some Preliminary results for the workshop on Wideband speech Quality : Prediction and Assessment. Mainz, 8-9 June 2004 -Even all the elements (coders, protocols, terminals,…) were developped, Wideband speech was not a success for ISDN; VoIP will certainly give the success. -Wideband speech increases the perceived quality and mainly the intelligibility, specially in noisy environment. - E-Model (G.107) and P.862 are now well known and used for narrow-band speech; some substancial progress are expected in the near future to predict and to assess wideband speech quality, and to assess the speech quality whatever the bandwidth. - The possibility to define "category" classes, based on acoustics and signal processing performance. 2020-01-05 3

4. Challenges for QoS Statements/Conclusions of ITU-T Workshop on QoS . Valid for HN/HS http://www.itu.int/ITU-T/worksem/qos/index.html • "Need for interworking standards to achieveend to end QoS" • "Need for a common understanding and implementation of QoS classes" whatever the network (cellular, wireless, wireline access) • "Generic requirements for IP QoS and traffic signalling"being developed in ITU-T SG 11(and on-going activities in Q.EE/11) TRQ.IPQOS.SIG.CS1(Y.1541/Y.1221 specifications are being applied, but work is still needed to enable implementation of QoS control-based networks." • "Need to define thespecific signalling system(s) to be used to implement assured QoS in IP-based networks. • The alternatives are - a broad consensus, or • - many gateways to be needed. • Need for collaborations/cooperations." 2020-01-05 4

5. Challenges for QoS Statements/Conclusions of ITU-T Workshop on QoS – Oct 2003Valid for HN/HS • "More work needed to understand the relationship betweenServiceLevelSpecification, monitoring and application monitoring" • "Ultimately the issue for accelerating deployment of QoS that fully supports the user experience is capital, which these days is only made available when persuasive business cases have been made " • A general remark, but well adapted to QoS • To ensure IP QoS interoperability it is needed to : • - ensure a high level leading role • - have experts from each relevant (standardisation) bodies working together, to understand each other aims, working methods, process and to work with coherent schedules • - ensure that the areas of work in progress are in line with the guidelines in the relevant bodies • - have the relevant support of the experts of a company, working in the different bodies. 2020-01-05 5

6. Rec. G.1000 "Communications quality of service: A framework and definitions" • Provides a framework and definitions for communications quality of service • Establishes a uniform approach to quality of service across the ITU-T

7. SG 12 Questions to be involved in cooperation on Home networking/Home services QUESTION O/12 – QoS and performance coordination The main focus are : - Coordination of QoS-related activities in the ITU-T (ongoing), with the focus on identifying gaps in QoS standardization that present interoperability obstacles to achieving e2e QoS. - Coordination among various standards activities on QoS and collaboration with other standards bodies (ongoing), with an emphasis on interoperability. 2020-01-05 7

8. Mapping of user-centric QoS requirements (G1010) • 8 distinct groupings, covering the range of applications • Distinction between applications which can tolerate some information loss and those that cannot • Main distinction in terms of delay

9. Benefit of end-user QoS category model • QoS Category Model is based on end to end user perception of impairments, therefore not dependent on any specific technology for its validity • Provides an indication of the upper and lower boundaries for applications to be perceived as essentially acceptable to the user • Shows how the underlying impairments of information loss and delay can be grouped appropriately, without implying that one class is “better” than another • Provides basis for realistic network QoS classes (in complementarity with ITU-T Rec. Y.1541)

10. SG 12 Questions to be involved in cooperation on Home networking/Home services • QUESTION M/12 – Multimedia QoE/QoS performance requirements and assessment methods • Main focus related to HN/HS : • Identify examples of multimedia applications and services (interactive, streaming, browsing, e-commerce, file transfer etc) and the underlying media involved (voice, video, still image, text, data etc). • - Development of new Rec. G.MMPERF, providing guidance on end-user performance expectations for multimedia applications • -Identify simple analysis techniques for estimating end to end performance for multimedia applications (“non-voice E-model”), including web-based applications, video conferencing and computer-supported cooperative work (CSCW). • - Development of simplified planning models for estimating end to end IP performance (eg G.E2EIPP) 2020-01-05 10

11. As an exemple for on-going G.MMPERF : On-line games Based on subjective tests with real users it appears that a target value of 70 ms as the maximum delay should be more appropriate than the preliminary value (200ms) the maximum delay variation around the mean value should be +/- 20ms, because the player adapts his playing to the latency, and a greater variation is annoying. (These limits are based on "acceptability testing"). Note : Some games (as FPS -First Person Shooting-) are very sensitive to this delay variation. For other games the maximum value could be limited to 150ms (These values are based on Games-on-line implemented on PC). The minimum data rate should be 40 kbit/s (for the client). This value shall be greater for the server. This is applicable to PC and consoles. It appears that the more popular "games on line" on PCs are IP loss tolerant. 2020-01-05 11

12. Other important topics related to QoS (on –going activities) • Quality assessment for Voice and multimedia Services • Subjective quality assesment (recently approved P.880 Continuous Evaluation of Time Varying Speech Qualityand P.851 Subjective quality evaluation of telephone services based on spoken dialogue systems) • Objective Quality assesment : 3 types of models are developped( Opinion models –E-Model, G.107-, Psychoacoustic models –P.862 and P.563 and models associated to INMD –P.562-). • - Quality assesment methodologies for multimedia services (SG9/SG12) • On-going work under a JRG Multimedia Quality Assessment 2020-01-05 12

13. SG 12 Questions to be involved in cooperation on Home networking/Home services • QUESTION K/12 - IP based multimedia services (e.g. voice, video, data) end to end transmission planning for multiple interconnected networks (e.g. cellular, wireless, wireline networks) • - QoS Interoperability Issues : • - Definition of interworking functions required to support interfacing between cellular/wireless/wireline networks sufficient to enable service providers to comply with end to end performance objectives for the QoS classes and to take into consideration the network performance parameters across network sections • - Analysis of the impacts of interworking functions between different network sections on end to end QoS. • - Apportionment functions and mechanisms • Static and dynamic allocation of performance parameter values across networks (cellular, wireless, wireline access and backbone networks) 2020-01-05 13

14. SG 12 Questions to be involved in cooperation on Home networking/Home services QUESTION B/12 - Speech transmission characteristics and measurement methods for terminals and gateways interfacing packet-switched (IP) networks - Enhancement of Recommendation P.1010 on Fundamental Voice Transmission Objectives for IP Terminals and Gatewaysregarding wideband telephony - Production of a new Recommendation P.VOIP-MM on Measurement Methodologies for IP Terminals and Gateways QUESTION C/12 – Speech transmission characteristics of speech terminals for fixed circuit-switched, mobile and packet-switched (IP) networks Speech transmission characteristics and measurement methods are needed for voice terminals using new access techniques (e.g., power line access, WLAN, etc.) 2020-01-05 14

15. Other important topics related to QoS (on –going activities) • Handbook on QoS will be available soon (prepared by WP2/2) • - On-going work on network performance : • - Ethernet (Y.ethperf) • - Hybrid networks (Y.hybperf) • Note that other relevant recommendations have been approved recently : • - Y.1561: Performance and availability parameters for MPLS networks (may 2004) • - Y.1560: TCP performance parameters and objectives (september 2003) 2020-01-05 15

16. Important topics on QoS in ITU-T (other than those presented by SG 9 and 12) SG 13 has initiated works under JRG-NGN Recommendation Y.1291 (ex-Y.qosar) "An architectural framework for support of Quality of Service (QoS) in Packet networks has been approved in early may. Still under development (meeting this week inGeneva) Draft Recommendation Y. 123.qos "A QoS Architecture for Ethernet-Based IP Access Network" It is a basis tospecifiy a layered reference model and methods for support of QoS in Ethernet-based IP access network and associated protocol requirements. SG 11, on-going work on QoS signalling. Progress also expected in the new NGN Focus Group 2020-01-05 16

17. Thanks Questions? Jeanyves.monfort@francetelecom.com 2020-01-05 17