1、 International Telecommunication Union ITU-T E.800TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (09/2008) SERIES E: OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS Quality of telecommunication services: concepts, models, objectives and dependability planning Terms
2、 and definitions related to the quality of telecommunication services Definitions of terms related to quality of service Recommendation ITU-T E.800 ITU-T E-SERIES RECOMMENDATIONS OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS INTERNATIONAL OPERATION Definitions E.1
3、00E.103 General provisions concerning Administrations E.104E.119 General provisions concerning users E.120E.139 Operation of international telephone services E.140E.159 Numbering plan of the international telephone service E.160E.169 International routing plan E.170E.179 Tones in national signalling
4、 systems E.180E.189 Numbering plan of the international telephone service E.190E.199 Maritime mobile service and public land mobile service E.200E.229 OPERATIONAL PROVISIONS RELATING TO CHARGING AND ACCOUNTING IN THE INTERNATIONAL TELEPHONE SERVICE Charging in the international telephone service E.2
5、30E.249 Measuring and recording call durations for accounting purposes E.260E.269 UTILIZATION OF THE INTERNATIONAL TELEPHONE NETWORK FOR NON-TELEPHONY APPLICATIONS General E.300E.319 Phototelegraphy E.320E.329 ISDN PROVISIONS CONCERNING USERS E.330E.349 INTERNATIONAL ROUTING PLAN E.350E.399 NETWORK
6、MANAGEMENT International service statistics E.400E.404 International network management E.405E.419 Checking the quality of the international telephone service E.420E.489 TRAFFIC ENGINEERING Measurement and recording of traffic E.490E.505 Forecasting of traffic E.506E.509 Determination of the number
7、of circuits in manual operation E.510E.519 Determination of the number of circuits in automatic and semi-automatic operation E.520E.539 Grade of service E.540E.599 Definitions E.600E.649 Traffic engineering for IP-networks E.650E.699 ISDN traffic engineering E.700E.749 Mobile network traffic enginee
8、ring E.750E.799 QUALITY OF TELECOMMUNICATION SERVICES: CONCEPTS, MODELS, OBJECTIVES AND DEPENDABILITY PLANNING Terms and definitions related to the quality of telecommunication services E.800E.809 Models for telecommunication services E.810E.844 Objectives for quality of service and related concepts
9、 of telecommunication services E.845E.859 Use of quality of service objectives for planning of telecommunication networks E.860E.879 Field data collection and evaluation on the performance of equipment, networks and services E.880E.899 OTHER E.900E.999 For further details, please refer to the list o
10、f ITU-T Recommendations. Rec. ITU-T E.800 (09/2008) i Recommendation ITU-T E.800 Definitions of terms related to quality of service Summary Recommendation ITU-T E.800 provides a set of commonly used terms in the study and management of quality of service (QoS). The technical and non-technical terms
11、related to the QoS listed in this Recommendation are intended to represent the interests of all parties of telecommunications service market, i.e., user, service provider, manufacturer and regulator. The definition of terms is in the context of QoS. Some terms may be defined differently in other doc
12、uments in another context. Therefore, care should be taken in the use of such terms in their appropriate context. For a comprehensive set of QoS terms, one is referred to Recommendations related to specific services or performance characteristics. Source Recommendation ITU-T E.800 was approved on 23
13、 September 2008 by ITU-T Study Group 2 (2005-2008) under the WTSA Resolution 1 procedure. ii Rec. ITU-T E.800 (09/2008) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (IC
14、Ts). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication
15、 Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of infor
16、mation technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agen
17、cy. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some
18、other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or im
19、plementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development proc
20、ess. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongl
21、y urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2009 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T E.800 (09/2008) iii CONTENTS Page 1 Introduction 1 1.1 Overview 1
22、1.2 General guide to concepts 1 2 General terms 2 3 Quality-of service terms . 5 3.1 Service related terms 5 3.2 Network-related terms 12 3.3 Management-related terms . 14 Annex A Related QoS/NP Handbooks and E-Series Recommendations . 17 Annex B List of recommended abbreviations. 20 Index Alphabeti
23、cal list of definitions contained in this Recommendation . 21 Rec. ITU-T E.800 (09/2008) 1 Recommendation ITU-T E.800 Definitions of terms related to quality of service 1 Introduction 1.1 Overview Terminology standardization is necessary for two main reasons: to avoid confusion to standards users by
24、 introducing conflicting terms and definitions; to assist alignment between the various groups involved in telecommunication standards development. A consistent set of terms and definitions is required, therefore, to develop the important areas of quality of service (QoS) and network performance (NP
25、). The technical and non-technical terms related to the QoS listed in this Recommendation are intended to represent the interests of all parties of telecommunications service market, i.e., user, service provider, manufacturer and regulator. The definition of terms is in the context of QoS. Some term
26、s may be defined differently in other documents in another context. Therefore, care should be taken in the use of such terms in their appropriate context. The intention of this Recommendation is to set out a comprehensive set of terms and definitions relating to these concepts. These collective term
27、s and definitions can be universally applied to all telecommunication services and the network arrangements used to provide these. This Recommendation is intended to cover the commonly used terms in the study and management of QoS. For a comprehensive set of QoS terms, one is referred to Recommendat
28、ion(s) related to specific services or performance characteristics. 1.2 General guide to concepts The end-to-end QoS depends on the contributions made by the components as illustrated in Figure 1. Figure 1 Schematic contributions to end-to-end QoS NOTE 1 The configuration illustrated above is for th
29、e conventional service with users at each end of a connection. However, the principle of this configuration may be applied to services offered by a service provider at one end and user/s at the other end. NOTE 2 Terminal equipment: Contribution to the end-to-end QoS could depend on the variability o
30、f the performance of the terminal equipment. NOTE 3 Access network: The contributions of access network to the end-to-end QoS depend on the combination of access medium and technology used for a particular service (e.g., wireless, cable, ADSL etc.). NOTE 4 Core network: The core network may be a sin
31、gle provider or a concatenation of different providers networks. QoS contribution to end-to-end performance from core network will be governed by the contributions from individual network components (whether single provider or multi providers); technology used (digital multiplexing, IP, etc.) transm
32、ission media (air, cable optical or metal) and other factors. 2 Rec. ITU-T E.800 (09/2008) To specify the end-to-end QoS, it is necessary to state the specified operating conditions in which a service is supported over a connection (connectionless or connection oriented) that takes place. The QoS co
33、uld also be altered for a given set of specified operating conditions by environmental conditions, such as traffic and routing. Figure 2 illustrates the relationship between QoS and network performance (NP). QoS comprises both network performance and non-network related performance. Examples of NP a
34、re bit error rate, latency, etc., and for non-network performance provision time, repair time, range of tariffs and complaints resolution time, etc. The list of QoS criteria for a particular service would be dependent upon the service and their relevance could vary among the segments of the customer
35、 population. Figure 2 Quality of service comprises network and non-network criteria At a more detailed level, QoS can be divided into four viewpoints as illustrated in Figure 3. This concept is described further in ITU-T G.1000. A generic definition of QoS is derived from a definition of quality and
36、 is given in clause 2. Of particular interest is QoS experienced by the user (expressed by QoSE or QoSP QoS perceived). QoSE is influenced by the delivered QoS and the psychological factors influencing the perception of the user. Understanding of the QoSE is of primary importance to help optimize re
37、venue and resources of the service provider. Figure 3 Four viewpoints of quality of service Various issues related to QoS are brought together in ITU-T E.802. It also shows the inter-relationship between various QoS aspects. 2 General terms 2.1 Quality The totality of characteristics of an entity th
38、at bear on its ability to satisfy stated and implied needs. NOTE The characteristics should be observable and/or measurable. When the characteristics are defined, they become parameters and are expressed by metrics (see clauses 2.7 to 2.13). Rec. ITU-T E.800 (09/2008) 3 2.2 Quality of service (QoS)
39、Totality of characteristics of a telecommunications service that bear on its ability to satisfy stated and implied needs of the user of the service. 2.3 QoS requirements of user/customer (QoSR) A statement of QoS requirements by a customer/user or segment/s of customer/user population with unique pe
40、rformance requirements or needs. NOTE The customer/user needs may be expressed in descriptive terms (criteria) listed in the order of priority, with preferred performance value for each criterion. The service provider then translates these into parameters and metrics pertinent to the service (see IT
41、U-T E.802). 2.4 QoS offered/planned by service provider (QoSO) A statement of the level of quality planned and therefore offered to the customer by the service provider. NOTE Level of QoS the service provider plans to achieve (and therefore offers) to the customer/user is expressed by target values
42、(or range) for measures of parameters pertinent to a specified service. 2.5 QoS delivered/achieved by service provider (QoSD) A statement of the level of QoS achieved or delivered to the customer. NOTE Achieved or delivered QoS is expressed by metrics for the pertinent parameters for a service. 2.6
43、QoS experienced/perceived by customer/user (QoSE) A statement expressing the level of quality that customers/users believe they have experienced. NOTE 1 The level of QoS experienced and/or perceived by the customer/user may be expressed by an opinion rating. NOTE 2 QoSE has two main man components:
44、quantitative and qualitative. The quantitative component can be influenced by the complete end-to-end system effects (network infrastructure). NOTE 3 The qualitative component can be influenced by user expectations, ambient conditions, psychological factors, application context, etc. NOTE 4 QoSE may
45、 also be considered as QoSD received and interpreted by a user with the pertinent qualitative factors influencing his/her perception of the service. 2.7 Characteristic A property which helps to differentiate between the individuals of a given population. NOTE The differentiation may be either quanti
46、tative (by variables) or qualitative (by attributes). 2.8 Criterion Collections of characteristics or a single characteristic, as appropriate, to describe benefit to user of a product or a service. 2.9 Parameter A quantifiable characteristic of a service with specified scope and boundaries. Example:
47、 The parameter for estimating the misdialling probability would be expressed as: The number of misdialled calls per 100 call attempts. NOTE Parameters may be objective or subjective. 2.10 Objective (Quantitative) parameters Parameters that are measurable (with instruments or observations) and a perf
48、ormance value assigned quantitatively may be classified as objective parameters. NOTE Examples: error rate of a channel, repair time. 4 Rec. ITU-T E.800 (09/2008) 2.11 Subjective (Qualitative) parameters Parameters that can be expressed using human judgment and understanding may be classified as sub
49、jective or qualitative parameters. NOTE 1 Qualitative parameters are expressed by opinion ratings. NOTE 2 Example: The ergonomic quality of a mobile handset (feel good factor) may be expressed by ratings on a given scale. 2.12 Measure A unit by which a parameter may be expressed. Example: Waiting time for provision of a service may be expressed as calendar or working days. 2.13 Metric (also called Indicator) Value calculated from observed attribute/s of a measure. NOTE 1 When the tempera
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