SIST-V ETSI/EG 202 009-1 V1.3.1:2016

ETSI GUIDE
User Group;
Quality of telecom services;
Part 1: Methodology for identification of indicators
relevant to the Users
2 ETSI EG 202 009-1 V1.3.1 (2014-12)

Reference
REG/USER-00042-1
Keywords
QoS, quality, service, SLA, user
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3 ETSI EG 202 009-1 V1.3.1 (2014-12)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Introduction . 5
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 7
3 Definitions and abbreviations . 9
3.1 Definitions . 9
3.2 Abbreviations . 17
4 About telecommunication service QoS . 17
4.1 About telecommunication services . 17
4.2 Services versus offers . 17
4.3 About Quality of Services . 18
4.4 SLO (Service Level Objective) . 18
5 Scope of telecommunications offers . 19
6 Methodology to identify the customer's QoS requirements . 20
6.1 Matrix for the determination of communications QoS criteria . 22
6.1.1 Matrix line Y1 - Sales . 24
6.1.1.1 Matrix line Y1.1 - Preliminary information/Advertisement . 24
6.1.1.2 Matrix line Y1.2 - Establishment of the contract (Terms and conditions) . 26
6.1.2 Matrix line Y2 - Service provisioning . 27
6.1.3 Matrix line Y3 - Service alteration/Technical upgrade . 28
6.1.3.1 Matrix line Y-3.1 - Service alteration . 28
6.1.3.2 Matrix line Y-3.2 - Technical upgrade . 30
6.1.4 Matrix line Y4 - Service support . 31
6.1.4.1 Matrix line Y4.1 - Documentation . 31
6.1.4.2 Matrix line Y4.2 and Y4.3 - Technical and commercial support . 32
6.1.4.3 Matrix line Y4.4 - Complaint management . 33
6.1.5 Matrix line Y5 - Repair-Troubleshooting . 34
6.1.6 Matrix line Y6 - Metering/Charging/Billing . 35
6.1.7 Matrix line Y7 - Cessation . 37
6.1.8 Matrix line Y8 - Network/service management by the customer . 38
6.1.9 Matrix line Y9 - Service utilization . 39
6.2 Recommendations to fulfil the table cells . 44
6.2.1 Service specific assessable metrics . 44
6.2.2 Prioritization . 45
6.2.3 Selection of the user sample . 45
6.2.4 Practical means to define the SLO . 45
6.3 QoS requirements review . 45
7 Measurements . 46
7.1 Objective measurements . 46
7.1.1 Intrusive measurements . 46
7.1.2 Non-intrusive measurements . 46
7.2 Subjective measurements . 46
7.3 Measurement by a third party . 47
7.4 Who should perform the measurements . 47
7.5 Result presentation . 47
8 Conclusion . 47
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4 ETSI EG 202 009-1 V1.3.1 (2014-12)
Annex A: Bibliography . 48
History . 49

ETSI
5 ETSI EG 202 009-1 V1.3.1 (2014-12)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://ipr.etsi.org).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This ETSI Guide (EG) has been produced by ETSI User Group (USER).
The present document is part 1 of a multi-part deliverable covering the quality of telecom services, as identified below:
Part 1: "Methodology for identification of indicators relevant to the Users";
Part 2: "User related indicators on a service specific basis";
Part 3: "Template for Service Level Agreements (SLA)".
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "may not", "need", "need not", "will",
"will not", "can" and "cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms
for the expression of provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Introduction
Quality in the service area can be evaluated from different perspectives and therefore using different measurement
methods:
a) the first is related to the reliability of the equipment and can be measured accurately via technical means,
although these measurements might be expensive because of both the dispersion of the test results and the size
of the sample to be tested;
b) the second is related to the service provision and is closely linked to the kind of use of the service. Therefore
appropriate indicators have to be defined according to use;
c) the last is intended to measure the subjective satisfaction of the customer and there is often no other means
than a survey to get it.
In the two first categories, technical means can be used to perform the measurements and in such cases, standards are
often useful to achieve a common approach; such standards are given as references where appropriate. They include a
precise definition of what is meant as a failure: total failure, poor performance, backup situation, etc.
Assessing these different aspects is of paramount importance to the provider who endeavours to improve the offered
QoS. From a user viewpoint, the end-to-end QoS is the most relevant. Hence objective and subjective measurements
may be usefully combined for a better assessment of the QoS.
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6 ETSI EG 202 009-1 V1.3.1 (2014-12)
Measurements of every potentially interesting indicator all the time might be very expensive and could even jeopardize
service performances. It is often cheaper to get them via a poll. In addition, it may be convenient to rely on a third party
and also audit to carry out these measurements in order to avoid any criticism from one of the involved parties.
The present document is dedicated to the methodology to analyse the user's needs which is the first step in a Total
Quality Management (TQM) process.
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7 ETSI EG 202 009-1 V1.3.1 (2014-12)
1 Scope
In the current competitive world, Quality of Service (QoS) is becoming, jointly with cost, a key indicator in selling and
buying telecommunications services. At the same time, technology and liberalization trends are raising new types of
concerns unknown with the Plain Old Telephony Services (POTS) using switched connections provided by a single
monopoly supplier.
Nowadays, there are several standards describing QoS measurements but the questions of which indicators are to be
monitored and which values they should meet are still open. The present document proposes a methodology for the
identification of indicators relevant to the users that can be used either to monitor the QoS of Telecom services used by
the private customers or for a Service Level Agreement (SLA) between a business customer and a supplier of
Telecommunications services such as that proposed in ETSI EG 202 009-3 [i.22]. This part 3 gives guidelines on how
to express explicit user's QoS requirements, prioritize the indicators, establish a preferred value for each of these
indicators, while ETSI EG 202 009-2 [i.21] proposes QoS indicators for each service and each step of the Customer
Relationship Course.
The present document was written to make available to the providers and users of any kind of telecom services (legacy
network based or IP network based services) a common basis for mutual understanding about quality of service. It aims
to assist users in identifying rationally their QoS requirements in terms of Service Level Objectives (SLO), helping the
providers to better meet them for their mutual benefit.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are necessary for the application of the present document.
Not applicable.
2.2 Informative references
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] Recommendation ITU-T E.721: "Network grade of service parameters and target values for
circuit-switched services in the evolving ISDN".
[i.2] Recommendation ITU-T E.800: "Telephone network and ISDN quality of service, network
management and traffic engineering: Terms and definitions related to quality of service and
network performance including dependability".
[i.3] Recommendation ITU-T G.107: "The E-Model, a computational model for use in transmission
planning".
[i.4] Recommendation ITU-T G.109: "Definition of categories of speech transmission quality".
[i.5] Recommendation ITU-T G.111: "Loudness ratings (LRs) in an international connection".
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8 ETSI EG 202 009-1 V1.3.1 (2014-12)
[i.6] Recommendation ITU-T G.1000: "Communications Quality of Service: A framework and
definitions".
[i.7] Recommendation ITU-T I.112-417: "Vocabulary of terms for ISDNs".
[i.8] Recommendation ITU-T I.113: "Vocabulary of terms for broadband aspects of ISDN".
[i.9] Recommendation ITU-T I.350: "General aspects of quality of service and network performance in
digital networks, including ISDNs".
[i.10] Recommendation ITU-T I.430: "Basic user-network interface - Layer 1 specification".
[i.11] Recommendation ITU-T I.431: "Primary rate user-network interface - Layer 1 specification".
[i.12] Recommendation ITU-T M 60: "Maintenance terminology and definitions".
[i.13] Recommendation ITU-T O.172: "Jitter and wander measuring equipment for digital systems which
are based on the synchronous digital hierarchy (SDH)".
[i.14] Recommendation ITU-T P.10/G.100: "Vocabulary for performance and quality of service".
[i.15] Recommendation ITU-T P.800.1: "Mean Opinion Score (MOS) terminology".
[i.16] ETSI ETR 003: "Network Aspects (NA); General aspects of Quality of Service (QoS) and
Network Performance (NP)".
[i.17] ETSI ETR 138: "Network Aspects (NA);Quality of service indicators for Open Network Provision
(ONP) of voice telephony and Integrated Services Digital Network (ISDN)".
[i.18] ETSI EG 201 013: "Human Factors (HF); Definitions, abbreviations and symbols".
[i.19] ETSI EG 201 219: "User requirements; Guidelines on the consideration of user requirements when
managing the standardization process".
[i.20] ETSI EG 201 940: "Human Factors (HF); User identification solutions in converging networks".
[i.21] ETSI EG 202 009-2: "User Group; Quality of telecom services; Part 2: User related parameters on
a service specific basis".
[i.22] ETSI EG 202 009-3: "User Group; Quality of telecom services; Part 3: Template for Service Level
Agreements (SLA)".
[i.23] ETSI EG 202 843: "User Group; Quality of ICT services; Definitions and methods for assessing
the QoS parameters of the customer relationship stages other than utilization".
[i.24] ETSI ES 202 057-1: "Speech Processing, Transmission and Quality Aspects (STQ); User related
QoS parameter definitions and measurements; Part 1: General".
[i.25] ETSI GS ISI 003: "Information Security Indicators (ISI); Key Performance Security Indicators
(KPSI) to evaluate the maturity of security event detection".
[i.26] ETSI TR 101 287: "Services and Protocols for Advanced Networks (SPAN); Terms and
definitions".
[i.27] ETSI TR 101 329-1: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; End-to-end Quality of Service in TIPHON systems; Part 1: General aspects
of Quality of Service (QoS)".
[i.28] ETSI TR 101 830-1: "Transmission and Multiplexing (TM); Access networks; Spectral
management on metallic access networks; Part 1: Definitions and signal library".
[i.29] ETSI TR 102 008: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; Terms and Definitions".
[i.30] ETSI TR 102 276: "User Group; Users' Quality of Service Criteria for Internet Access in Europe".
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9 ETSI EG 202 009-1 V1.3.1 (2014-12)
[i.31] ETSI TR 121 905: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); LTE; Vocabulary for 3GPP Specifications".
[i.32] ETSI TS 101 329-5: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; End-to-end Quality of Service in TIPHON systems; Part 5: Quality of
Service (QoS) measurement methodologies".
[i.33] ETSI TS 102 728: "Digital Video Broadcasting (DVB); Globally Executable MHP (GEM)
Specification 1.3 (including OTT and hybrid broadcast/broadband)".
[i.34] ETSI TS 102 844: "User Group; Quality of Telecom Services; Conformity assessment;
Requirements for bodies providing QoS assessments and surveys".
[i.35] ETSI TS 102 845: "User Group; Quality of ICT Services; Requirements for Check-up on Metering
and Billing Processes".
[i.36] ETSI TS 102 846: "User Group; Quality of ICT Services; Requirements for Bodies Providing
Conformity Assessment of Checking-up on Metering and Billing Processes".
[i.37] ETSI TS 102 852: "User Group; Quality of ICT Services; Assessment process of the QoS
parameters of the customer relationship stages".
[i.38] ETSI EN 300 462-1-1: "Transmission and Multiplexing (TM); Generic requirements for
synchronization networks; Part 1-1: Definitions and terminology for synchronization networks".
[i.39] ISO/IEC 7498-2:"Information processing systems -- Open Systems Interconnection -- Basic
Reference Model -- Part 2: Security Architecture".
[i.40] ISO/IEC 9797-1: "Information technology -- Security techniques -- Message Authentication Codes
(MACs) -- Part 1: Mechanisms using a block cipher".
[i.41] ISO/IEC 11770-3: 1999: "Information technology -- Security techniques -- Key management --
Part 3: Mechanisms using asymmetric techniques".
[i.42] ISO/IEC 13888-1: "Information technology -- Security techniques -- Non-repudiation -- Part 1:
General".
[i.43] ISO/IEC 15408: "Information technology - Security techniques - Evaluation criteria for IT
security".
[i.44] ISO/IEC 15945: "Information technology -- Security techniques -- Specification of TTP services
to support the application of digital signatures".
[i.45] ISO/IEC 17021: "Conformity assessment - Requirements for bodies providing audit and
certification of management systems".
[i.46] ISO/IEC 18028-4:2005: "Information technology -- Security techniques -- IT network security --
Part 4: Securing remote access".
[i.47] ISO/IEC 20000: "Information technology -- Service management -- Part 2: Guidance on the
application of service management systems".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
(service) accessibility: ability of a component or service to perform its required function at a stated instant or over a
stated period of time, within specified tolerances and other given conditions, when requested by the user
NOTE: For readability accessibility is used alone in the current document but stands for "service accessibility"
and not "accessibility for all".
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10 ETSI EG 202 009-1 V1.3.1 (2014-12)
assurance (in the supplier-customer interface): knowledge and courtesy of employees and their ability to convey
trust and confidence
audit: control carried out by a third party on the compliance of a provider organization to a code of practice or a
regulation
authentication: provision of assurance of the claimed identity of an entity
NOTE: See ISO/IEC 18028-4 [i.46].
authorization: granting of permission based on authenticated identification (see ISO/IEC 7498-2 [i.39])
availability: likelihood with which the relevant components of the service function can be accessed, at the instant of
request, as required by the specified conditions, in particular those related to open hours, geographic coverage and
resource size aspects if any
NOTE: See ETSI ETR 003 [i.16] modified.
call: any connection (fixed or temporary) capable of transferring information between two or more users of a
telecommunications system. In this context a user may be a person or a machine
call set-up time: period starting when the address information required for setting up a call is received by the network
(e.g. recognized on the calling user's access line) and finishing when the called party busy tone or ringing tone or
answer signal is received by the calling party (e.g. recognized on the calling user's access line)
NOTE 1: See ETSI ETR 138 [i.17].
NOTE 2: In some standards, Post Dialling Delay (PDD) is used instead of call set-up time. (See the definition
below (ETSI TS 101 329-5 [i.32])).
capacity: ability of an item to meet a demand of a given size under given internal conditions
NOTE: In the present set of documents, the reader should have in mind that, if SLO are expected with regard to
this criterion, these SLO are the expression of a trade off between a user and the provider i.e. a
contractual commitment. If a measurement is done in this domain, it is not a QoS assessment per se but
rather a check up of the conformance to the SLO of both the use by the customer(s) and the means made
available by the provider.
certificate: certificate issued by a certification body in accordance with the conditions of its accreditation and bearing
an accreditation symbol or statement
cessation: all activities associated with the cessation of a telecommunication service from the time it was requested by a
customer, to the time it was completed to the satisfaction of the customer
charging/billing: all relevant activities associated with the charging and billing for a telecommunication service to a
customer
Charging Data Record (CDR): formatted collection of information about a chargeable event (e.g. time of call set-up,
duration of the call, amount of data transferred, etc.) for use in billing and accounting
NOTE: For each party to be charged for parts of or all charges of a chargeable event a separate CDR should be
generated, i.e. more than one CDR may be generated for a single chargeable event, e.g. because of its
long duration, or because more than one charged party is to be charged (see ETSI TR 121 905 [i.31]).
Circuit Loudness Rating (CLR): loudness loss between two electrical interfaces in a connection or circuit, each
interface terminated by its nominal impedance which may be complex
NOTE: See ETSI TR 102 008 [i.29].
connection: connection provides for transfer of information between endpoints
NOTE: See Recommendation ITU-T I.113-504 modified [i.8].
connection set up time: time between end of dialling and start of display of the first screen of a web page
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11 ETSI EG 202 009-1 V1.3.1 (2014-12)
defect: limited interruption of the ability of an item to perform a required function
NOTE 1: It may or may not lead to maintenance actions depending on the results of additional analysis.
NOTE 2: See Recommendation ITU-T I.113- 601 [i.8].
dependability (in the supplier-customer interface): the ability to provide what was promised, dependably and
accurately
digital signature: data appended to, or a cryptographic transformation of, a data unit that allows a recipient of the data
unit to prove the origin and integrity of the data unit and protect the sender and the recipient of the data unit against
forgery by third parties and sender against forgery by the recipient
NOTE: See ISO/IEC 11770-3 [i.41].
directory enquiry service: operator or machine based service intended to provide information on phone number,
addresses or e-mail addresses of people or organizations on user request
empathy (in the supplier-customer interface): degree of caring and individual attention provided to customers
encryption: (reversible) transformation of data by a cryptographic algorithm to produce ciphertext, i.e. to hide the
information content of the data
NOTE: See ISO/IEC 9797-1 [i.40].
fault: inability of an item to perform a required function, excluding that inability due to preventive maintenance, lack of
external resources, or planned actions
NOTE: See Recommendation ITU-T I.113-603 [i.8].
flexibility: ability of a service to be customized with elasticity and scalability features
NOTE: Flexibility embraces:
- Customization: options required by the customer and offered by the provider in order to
accommodate special requirements, i.e. the ability for the customer to adjust some specific features
of the subscribed service, e.g. additional features or some configuration parameters.
- Elasticity: variable resource allocation.
- Scalability: ability to size the system configuration.
function: process which conveys or transforms data in a predictable way, it may be affected by hardware, software or a
combination of the two
NOTE: See ETSI TS 102 728 [i.33].
identification: process of establishing the identity of an object or person
NOTE: See ETSI EG 201 940 [i.20].
indicator: when a metric is defined with boundaries and scope unambiguously and clearly stated this then becomes an
indicator
integrity: property of a system such that information offered at an input is delivered unchanged at an output
NOTE: See ETSI TR 101 287 [i.26].
jitter: functional description for measuring output jitter at a digital interface can be found in Recommendation
ITU-T O.172 [i.13]
KPI: metric capturing some aspects of the performance of one or more resources (including supplier resources or
services) which is measured either directly, or could be defined in hierarchies
NOTE 1: A KPI is meaningful to the SP, but not necessarily to the Customer.
NOTE 2: See TMF SLA Management Handbook.
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KQI: metric capturing some aspects of the performance of a Service or a Product, meaningful to the Customer
NOTE 1: A KQI is typically expressed as a percentage of customers, resources or telecom entities (like a call or a
session) meeting a certain level of quality.
NOTE 2: A KQI possibly aggregates a mix of KPIs, intermediate computed components (usually from KPIs), other
KQIs (from one or even several SPs) and direct measurements, using appropriate mathematical formulas
(which are the KQI Estimators).
NOTE 3: See TMF SLA Management Handbook.
Loudness Rating (LR): objective measure of the loudness loss, i.e. a weighted, electro-acoustic loss between certain
interfaces in the telephone network
NOTE 1: If the circuit between the interfaces is subdivided into sections, the sum of the individual section LRs is
equal to the total LR. In loudness rating contexts, the subscribers are represented from a measuring point
of view by an artificial mouth and an artificial ear respectively, both being accurately specified
(Recommendation ITU-T G.111 [i.5], ETSI TR 101 329-1 [i.27]).
NOTE 2: As used in the G-Series Recommendations for planning.
Mean Opinion Score (MOS): mean of opinion scores, i.e. of the values on a predefined scale that subjects assign to
their opinion of the performance of the telephone transmission system used either for conversation or for listening to
spoken material (according to Recommendations ITU-T. P.10/G.100 [i.14] and P.800.1 [i.15])
NOTE 1: Apart from subjective opinion, the abbreviation MOS is also used for scores that originate from objective
models or network planning models. The following identifiers are recommended to be used together with
the abbreviation MOS in order to distinguish the area of application, where N refers to narrow-band,
W refers to wideband, LQ refers to Listening Quality, CQ refers to Conversational Quality, S refers to
Subjective, O refers to Objective, and E refers to Estimated.
Listening-only Conversational Talking

Subjective MOS-LQSy MOS-CQSy MOS-TQSy
Objective MOS-LQOy MOS-CQOy MOS-TQOy
Estimated MOS-LQEy MOS-CQEy MOS-TQEy

NOTE 2: The letter "y" at the end of above acronyms is a placeholder for the descriptor of the respective audio
bandwidth, see the following provisional instructions:
- N for MOS scores obtained for narrow-band (300-3 400 Hz) speech relative to a narrow-band
high quality reference. This is applicable for instance to narrow-band only subjective tests or to
P.862.1 scores.
- W for MOS scores obtained for wideband (50-7 000 Hz) speech relative to a wideband high
quality reference. This is applicable for instance to wideband only subjective tests or to P.862.2
scores.
- M for MOS scores obtained for narrow-band or wideband speech relative to a wideband high
quality reference in a mixed bandwidths context. This is applicable for instance to mixed
bandwidths subjective tests.
The effects of audio bandwidth on MOS scores are currently under investigation in ITU-T Study
Group 12. In cases where the bandwidth denominators N, W or M do not properly reflect the
actual situation, it is suggested that provisionally the placeholder "y" be replaced by a proper
notation.
NOTE 3: The MOS ranges from 1 (lowest quality) to 5 (highest quality).
metric: QoS measurement related to a particular QoS criterion
NOTE 1: Several metrics may be needed for an extensive assessment of the quality of a service with respect to a
single criterion.
NOTE 2: Several indicators may be needed to assess a single metric.
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13 ETSI EG 202 009-1 V1.3.1 (2014-12)
monitoring: use of any available technical tool to assess permanently or for a given period of time a particular QoS
indicator, e.g. a server load or the response time for a directory enquiry service
network/service management by the user/customer: all activities associated with the customer's control of predefined
changes to telecommunication services or network configurations
NOTE: See ETSI ETR 003 [i.16].
non-repudiation: ability to prove an action or event has taken place, so that this event or action cannot be repudiated
later
NOTE: See ISO/IEC 13888-1 [i.42] and ISO/IEC 7498-2 [i.39].
offer: all the service components needed for the relationship between the customer and the provider along the whole
customer relationship course
Opinion Rating (OR): quantitative value (a number) assigned to a qualitative performance criterion on a predefined
rating scale to reflect the merit of that criterion to a user/customer
NOTE: More details are available in clause 4.1 of ETSI EG 202 843 [i.23].
overall transmission quality rating (R): full acoustic-to-acoustic (mouth to ear) quality, experienced by an average
user, for a typical situation using a "standard" telephony handset
NOTE 1: The overall transmission quality rating is calculated using the E-Model (see Recommendation
ITU-T G.107 [i.3]). The relation between overall transmission quality rating (R) and user perception of
quality is defined in Recommendation ITU-T G.109 [i.4].
NOTE 2: See ETSI TR 102 276 [i.30].
performance: measure of how well a transmission system fulfils defined criteria under specified conditions
NOTE: Adapted from ETSI TR 101 830-1 [i.28].
poll: panel of a sufficient number of users or observers are asked to assess a particular QoS parameter, e.g. "Delay to
provide a draft contract"
Post Dialling Delay (PDD): time in milliseconds between dialling the last digit and an audible tone being heard at the
originating end
NOTE 1: The audible tone is typically ring-back or the engaged tone (Recommendation ITU-T E.721 [i.1],
ETSI TS 101 329-5 [i.32]).
NOTE 2: Some systems have shown to present the user with a ring-back tone before a connection has been
established, this gives the impression that the PDD is low. If the connection fails this is later switched to
an engaged tone. This is an unacceptable operation and should be tested.
provision: all activities associated with the provision of a telecommunication service, from the time of effective
contract to the time the customer is able to use the service
QoS criterion: element of a set of characteristics of a service needed for an extensive assessment of the quality of this
service
Quality of Service (QoS): collective effect of service performance which determines the degree of satisfaction of a user
of the service
NOTE 1: The quality of service is characterized by the combined aspects of service support performance, service
operability performance, serve ability performance, service security performance and other factors
specific to each service.
NOTE 2: The term "quality of service" is not used to express a degree of excellence in a comparative sense nor is it
used in a quantitative sense for technical evaluations. In these cases a qualifying adjective (modifier)
should be used.
NOTE 3: See Recommendations ITU-T E.800 [i.2] and G.1000 [i.6].
ETSI
14 ETSI EG 202 009-1 V1.3.1 (2014-12)
NOTE 4: Complementary definition on QoS requirements of the user/customer, QoS offered by service provider,
QoS achieved by service provider, QoS perceived by the user/customer are given in ETSI ETR 003 [i.16].
Quality of Service Assessment Party (QoSAP): SP internal department or an independent third party expected to
manage the QoS assessment process, to analyse the data stored by the SP, to convene an expert panel, to launch a
customer survey and to gather the results
NOTE: A QoSAP can usefully be certified by a recognized certification body.
QoS achieved by service provider: statement of the level of quality achieved by the service provider
NOTE 1: See ETSI ETR 003 [i.16] and Recommendation ITU-T G.1000 [i.6] modified.
NOTE 2: This is expressed by values assigned to indicators, which are, as far as possible, same as those for the QoS
offered. These performance figures are summarized for specified periods of time, e.g. for the previous
3 months.
EXAMPLE: The service provider may state that the achieved accessibility for a given duration (e.g. one year)
was 99,95 % or unavailable for not more than 262,8 minutes over a 365 days year.
QoS offered by service provider: statement of the level of quality expected to be offered to the user/customer by the
service provider
NOTE 1: See ETSI ETR 003 [i.16] and Recommendation ITU-T G.1000 [i.6] modified.
NOTE 2: The level of quality is expressed by values assigned to QoS indicators. These parameters are usually
designed to be understandable to the user/customer. Each service would have its own set of QoS
parameters (see ETSI ETR 003 [i.16]).
EXAMPLE: A service provider may state that the accessibility of basic telephony service is 99,9 % in a year
with not more than a 15 minutes break on any one occasion.
QoS perceived by the user/customer: statement expressing the level of quality experienced by user/customers
NOTE 1: See ETSI ETR 003 [i.16] and Recommendation ITU-T G.1000 [i.6] modified.
NOTE 2: The QoS perceived is expressed, usually in terms of degrees of satisfaction and not in technical terms.
Technical terms may be expressed where the user/customer is able to understand and use these. QoS
perceived is assessed by customer surveys and from user's/customer's own comments on levels of service.
EXAMPLE: An user/customer may state that on unacceptable number of occasions there was difficulty in
getting through the network to make a call; a satisfaction rating of 2 may be given on a 4 point
scale.
QoS requirements of the user/customer: statement of the level of quality required by the applications of
customers/users of a service, which may be expressed non-technically
NOTE 1: See Recommendation ITU-T G.1000 [i.6].
NOTE 2: These requirements may be gathered for representative groupings of users/customers. For their own use,
the service provider may translate these into technical indicators easier to manage, if needed to better
fulfil the requirements.
reliability: ability of an item to perform a required function under stated conditions for a given time period
NOTE 1: See Recommendations ITU-T E.800 [i.2] and M.60 [i.12].
NOTE 2: It is generally assumed that the item is in a state to perform this required function at the beginning of the
time interval.
NOTE 3: In French, the term fiabilité is also used to denote the performance quantified by this probability.
reliability in the supplier-customer interface: ability to provide what was promised, dependably and accurately
repair: See trouble-shooting.
ETSI
15 ETSI EG 202 009-1 V1.3.1 (2014-12)
response time for directory enquiry services: duration from the instant when the address information required for
setting up a call is received by the network (e.g. recognized on the calling user's access line) to the instant the human
operator or an equivalent voice-activated response system answers the calling user to provide the number information
requested
NOTE: See ETSI ES 202 057-1 [i.24].
response time for operator services: duration from the instant when the address information required for setting up a
call is received by the network (e.g. recognized on the calling user's access line) to the instant the human operator
answers the calling user to provide the service requested
NOTE 1: See ETSI ES 202 057-1 [i.24].
NOTE 2: Services provided wholly automatically, e.g. by voice response systems are excluded
(ETSI ETR 138 [i.17]). The services covered are the services for operator controlled and assisted calls
that are accessed with special access codes. Access to emergency services is excluded.
NOTE 3: The period in this definition includes waiting times because operators are busy, and times for going
through voice response systems to reach the operator. However it excludes the handling of the call by the
operator, e.g. conversation with the operator. The reasons are that the variety of calls to operators is too
wide and that it is too difficult/costly in practice to measure the operator's performance precisely.
responsiveness (in the supplier-customer interface): willingness to help customers and provide prompt services
sales: all relevant activities from the time communications are established between the provider and the customer to the
time the contract is signed for the provision of a service by the provider
security: ability of a service to ensure the confidentiality of the pieces of information worked out, exchanged or stored,
the communication privacy, the authenticity and integrity of the information exchanged or stored as well as the
protection of the user and his communication means against any type of threat (virus, spam, etc.)
NOTE: Traceability (ability to verify the history, location, or application of an item by means of documented
recorded identification) is an additional important security element.
service: means of delivering value for the customer by facilitating results the customer wants to achieve
NOTE 1: Service is generally intangible.
NOTE 2: A service can also be delivered to the service provider by a supplier, an internal group or a customer
acting as a supplier.
NOTE 3: See ISO/IEC 20000 [i.47].
service alteration: all activities associated with the alteration of a telecommunication service, from the time alteration
to a service is requested by the customer to the time these alterations are carried to the satisfaction of the customer,
ETSI ETR 003 [i.16]
Service Level Objective (SLO): specific user requirement expressed as an assessable characteristic of the Service
Level (KQI)
NOTE: To fulfil a SLO, the provider may need to manage one or more QoS assessments (KPI) for each usage
context.
Service Provider (SP): organization that provides electronic communications services to users and customers
NOTE: From Recommendation ITU-T E.800 [i.2].
service support: all activities associated with the su
...

SLOVENSKI STANDARD
01-februar-2016
Uporabniška skupina - Kakovost telekomunikacijskih storitev - 1. del: Metodologija
za opredelitev kazalnikov, pomembnih za uporabnike
User Group- Quality of telecom services - Part 1: Methodology for identification of
indicators relevant to the Users
Ta slovenski standard je istoveten z: EG 202 009-1 V1.3.1
ICS:
03.120.99 Drugi standardi v zvezi s Other standards related to
kakovostjo quality
33.030 Telekomunikacijske Telecommunication services.
uporabniške rešitve Applications
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

ETSI GUIDE
User Group;
Quality of telecom services;
Part 1: Methodology for identification of indicators
relevant to the Users
2 ETSI EG 202 009-1 V1.3.1 (2014-12)

Reference
REG/USER-00042-1
Keywords
QoS, quality, service, SLA, user
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The content of the PDF version shall not be modified without the written authorization of ETSI.
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© European Telecommunications Standards Institute 2014.
All rights reserved.
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DECT , PLUGTESTS , UMTS and the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members.
TM
3GPP and LTE™ are Trade Marks of ETSI registered for the benefit of its Members and
of the 3GPP Organizational Partners.
GSM® and the GSM logo are Trade Marks registered and owned by the GSM Association.
ETSI
3 ETSI EG 202 009-1 V1.3.1 (2014-12)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Introduction . 5
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 7
3 Definitions and abbreviations . 9
3.1 Definitions . 9
3.2 Abbreviations . 17
4 About telecommunication service QoS . 17
4.1 About telecommunication services . 17
4.2 Services versus offers . 17
4.3 About Quality of Services . 18
4.4 SLO (Service Level Objective) . 18
5 Scope of telecommunications offers . 19
6 Methodology to identify the customer's QoS requirements . 20
6.1 Matrix for the determination of communications QoS criteria . 22
6.1.1 Matrix line Y1 - Sales . 24
6.1.1.1 Matrix line Y1.1 - Preliminary information/Advertisement . 24
6.1.1.2 Matrix line Y1.2 - Establishment of the contract (Terms and conditions) . 26
6.1.2 Matrix line Y2 - Service provisioning . 27
6.1.3 Matrix line Y3 - Service alteration/Technical upgrade . 28
6.1.3.1 Matrix line Y-3.1 - Service alteration . 28
6.1.3.2 Matrix line Y-3.2 - Technical upgrade . 30
6.1.4 Matrix line Y4 - Service support . 31
6.1.4.1 Matrix line Y4.1 - Documentation . 31
6.1.4.2 Matrix line Y4.2 and Y4.3 - Technical and commercial support . 32
6.1.4.3 Matrix line Y4.4 - Complaint management . 33
6.1.5 Matrix line Y5 - Repair-Troubleshooting . 34
6.1.6 Matrix line Y6 - Metering/Charging/Billing . 35
6.1.7 Matrix line Y7 - Cessation . 37
6.1.8 Matrix line Y8 - Network/service management by the customer . 38
6.1.9 Matrix line Y9 - Service utilization . 39
6.2 Recommendations to fulfil the table cells . 44
6.2.1 Service specific assessable metrics . 44
6.2.2 Prioritization . 45
6.2.3 Selection of the user sample . 45
6.2.4 Practical means to define the SLO . 45
6.3 QoS requirements review . 45
7 Measurements . 46
7.1 Objective measurements . 46
7.1.1 Intrusive measurements . 46
7.1.2 Non-intrusive measurements . 46
7.2 Subjective measurements . 46
7.3 Measurement by a third party . 47
7.4 Who should perform the measurements . 47
7.5 Result presentation . 47
8 Conclusion . 47
ETSI
4 ETSI EG 202 009-1 V1.3.1 (2014-12)
Annex A: Bibliography . 48
History . 49

ETSI
5 ETSI EG 202 009-1 V1.3.1 (2014-12)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://ipr.etsi.org).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This ETSI Guide (EG) has been produced by ETSI User Group (USER).
The present document is part 1 of a multi-part deliverable covering the quality of telecom services, as identified below:
Part 1: "Methodology for identification of indicators relevant to the Users";
Part 2: "User related indicators on a service specific basis";
Part 3: "Template for Service Level Agreements (SLA)".
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "may not", "need", "need not", "will",
"will not", "can" and "cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms
for the expression of provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Introduction
Quality in the service area can be evaluated from different perspectives and therefore using different measurement
methods:
a) the first is related to the reliability of the equipment and can be measured accurately via technical means,
although these measurements might be expensive because of both the dispersion of the test results and the size
of the sample to be tested;
b) the second is related to the service provision and is closely linked to the kind of use of the service. Therefore
appropriate indicators have to be defined according to use;
c) the last is intended to measure the subjective satisfaction of the customer and there is often no other means
than a survey to get it.
In the two first categories, technical means can be used to perform the measurements and in such cases, standards are
often useful to achieve a common approach; such standards are given as references where appropriate. They include a
precise definition of what is meant as a failure: total failure, poor performance, backup situation, etc.
Assessing these different aspects is of paramount importance to the provider who endeavours to improve the offered
QoS. From a user viewpoint, the end-to-end QoS is the most relevant. Hence objective and subjective measurements
may be usefully combined for a better assessment of the QoS.
ETSI
6 ETSI EG 202 009-1 V1.3.1 (2014-12)
Measurements of every potentially interesting indicator all the time might be very expensive and could even jeopardize
service performances. It is often cheaper to get them via a poll. In addition, it may be convenient to rely on a third party
and also audit to carry out these measurements in order to avoid any criticism from one of the involved parties.
The present document is dedicated to the methodology to analyse the user's needs which is the first step in a Total
Quality Management (TQM) process.
ETSI
7 ETSI EG 202 009-1 V1.3.1 (2014-12)
1 Scope
In the current competitive world, Quality of Service (QoS) is becoming, jointly with cost, a key indicator in selling and
buying telecommunications services. At the same time, technology and liberalization trends are raising new types of
concerns unknown with the Plain Old Telephony Services (POTS) using switched connections provided by a single
monopoly supplier.
Nowadays, there are several standards describing QoS measurements but the questions of which indicators are to be
monitored and which values they should meet are still open. The present document proposes a methodology for the
identification of indicators relevant to the users that can be used either to monitor the QoS of Telecom services used by
the private customers or for a Service Level Agreement (SLA) between a business customer and a supplier of
Telecommunications services such as that proposed in ETSI EG 202 009-3 [i.22]. This part 3 gives guidelines on how
to express explicit user's QoS requirements, prioritize the indicators, establish a preferred value for each of these
indicators, while ETSI EG 202 009-2 [i.21] proposes QoS indicators for each service and each step of the Customer
Relationship Course.
The present document was written to make available to the providers and users of any kind of telecom services (legacy
network based or IP network based services) a common basis for mutual understanding about quality of service. It aims
to assist users in identifying rationally their QoS requirements in terms of Service Level Objectives (SLO), helping the
providers to better meet them for their mutual benefit.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are necessary for the application of the present document.
Not applicable.
2.2 Informative references
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] Recommendation ITU-T E.721: "Network grade of service parameters and target values for
circuit-switched services in the evolving ISDN".
[i.2] Recommendation ITU-T E.800: "Telephone network and ISDN quality of service, network
management and traffic engineering: Terms and definitions related to quality of service and
network performance including dependability".
[i.3] Recommendation ITU-T G.107: "The E-Model, a computational model for use in transmission
planning".
[i.4] Recommendation ITU-T G.109: "Definition of categories of speech transmission quality".
[i.5] Recommendation ITU-T G.111: "Loudness ratings (LRs) in an international connection".
ETSI
8 ETSI EG 202 009-1 V1.3.1 (2014-12)
[i.6] Recommendation ITU-T G.1000: "Communications Quality of Service: A framework and
definitions".
[i.7] Recommendation ITU-T I.112-417: "Vocabulary of terms for ISDNs".
[i.8] Recommendation ITU-T I.113: "Vocabulary of terms for broadband aspects of ISDN".
[i.9] Recommendation ITU-T I.350: "General aspects of quality of service and network performance in
digital networks, including ISDNs".
[i.10] Recommendation ITU-T I.430: "Basic user-network interface - Layer 1 specification".
[i.11] Recommendation ITU-T I.431: "Primary rate user-network interface - Layer 1 specification".
[i.12] Recommendation ITU-T M 60: "Maintenance terminology and definitions".
[i.13] Recommendation ITU-T O.172: "Jitter and wander measuring equipment for digital systems which
are based on the synchronous digital hierarchy (SDH)".
[i.14] Recommendation ITU-T P.10/G.100: "Vocabulary for performance and quality of service".
[i.15] Recommendation ITU-T P.800.1: "Mean Opinion Score (MOS) terminology".
[i.16] ETSI ETR 003: "Network Aspects (NA); General aspects of Quality of Service (QoS) and
Network Performance (NP)".
[i.17] ETSI ETR 138: "Network Aspects (NA);Quality of service indicators for Open Network Provision
(ONP) of voice telephony and Integrated Services Digital Network (ISDN)".
[i.18] ETSI EG 201 013: "Human Factors (HF); Definitions, abbreviations and symbols".
[i.19] ETSI EG 201 219: "User requirements; Guidelines on the consideration of user requirements when
managing the standardization process".
[i.20] ETSI EG 201 940: "Human Factors (HF); User identification solutions in converging networks".
[i.21] ETSI EG 202 009-2: "User Group; Quality of telecom services; Part 2: User related parameters on
a service specific basis".
[i.22] ETSI EG 202 009-3: "User Group; Quality of telecom services; Part 3: Template for Service Level
Agreements (SLA)".
[i.23] ETSI EG 202 843: "User Group; Quality of ICT services; Definitions and methods for assessing
the QoS parameters of the customer relationship stages other than utilization".
[i.24] ETSI ES 202 057-1: "Speech Processing, Transmission and Quality Aspects (STQ); User related
QoS parameter definitions and measurements; Part 1: General".
[i.25] ETSI GS ISI 003: "Information Security Indicators (ISI); Key Performance Security Indicators
(KPSI) to evaluate the maturity of security event detection".
[i.26] ETSI TR 101 287: "Services and Protocols for Advanced Networks (SPAN); Terms and
definitions".
[i.27] ETSI TR 101 329-1: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; End-to-end Quality of Service in TIPHON systems; Part 1: General aspects
of Quality of Service (QoS)".
[i.28] ETSI TR 101 830-1: "Transmission and Multiplexing (TM); Access networks; Spectral
management on metallic access networks; Part 1: Definitions and signal library".
[i.29] ETSI TR 102 008: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; Terms and Definitions".
[i.30] ETSI TR 102 276: "User Group; Users' Quality of Service Criteria for Internet Access in Europe".
ETSI
9 ETSI EG 202 009-1 V1.3.1 (2014-12)
[i.31] ETSI TR 121 905: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); LTE; Vocabulary for 3GPP Specifications".
[i.32] ETSI TS 101 329-5: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; End-to-end Quality of Service in TIPHON systems; Part 5: Quality of
Service (QoS) measurement methodologies".
[i.33] ETSI TS 102 728: "Digital Video Broadcasting (DVB); Globally Executable MHP (GEM)
Specification 1.3 (including OTT and hybrid broadcast/broadband)".
[i.34] ETSI TS 102 844: "User Group; Quality of Telecom Services; Conformity assessment;
Requirements for bodies providing QoS assessments and surveys".
[i.35] ETSI TS 102 845: "User Group; Quality of ICT Services; Requirements for Check-up on Metering
and Billing Processes".
[i.36] ETSI TS 102 846: "User Group; Quality of ICT Services; Requirements for Bodies Providing
Conformity Assessment of Checking-up on Metering and Billing Processes".
[i.37] ETSI TS 102 852: "User Group; Quality of ICT Services; Assessment process of the QoS
parameters of the customer relationship stages".
[i.38] ETSI EN 300 462-1-1: "Transmission and Multiplexing (TM); Generic requirements for
synchronization networks; Part 1-1: Definitions and terminology for synchronization networks".
[i.39] ISO/IEC 7498-2:"Information processing systems -- Open Systems Interconnection -- Basic
Reference Model -- Part 2: Security Architecture".
[i.40] ISO/IEC 9797-1: "Information technology -- Security techniques -- Message Authentication Codes
(MACs) -- Part 1: Mechanisms using a block cipher".
[i.41] ISO/IEC 11770-3: 1999: "Information technology -- Security techniques -- Key management --
Part 3: Mechanisms using asymmetric techniques".
[i.42] ISO/IEC 13888-1: "Information technology -- Security techniques -- Non-repudiation -- Part 1:
General".
[i.43] ISO/IEC 15408: "Information technology - Security techniques - Evaluation criteria for IT
security".
[i.44] ISO/IEC 15945: "Information technology -- Security techniques -- Specification of TTP services
to support the application of digital signatures".
[i.45] ISO/IEC 17021: "Conformity assessment - Requirements for bodies providing audit and
certification of management systems".
[i.46] ISO/IEC 18028-4:2005: "Information technology -- Security techniques -- IT network security --
Part 4: Securing remote access".
[i.47] ISO/IEC 20000: "Information technology -- Service management -- Part 2: Guidance on the
application of service management systems".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
(service) accessibility: ability of a component or service to perform its required function at a stated instant or over a
stated period of time, within specified tolerances and other given conditions, when requested by the user
NOTE: For readability accessibility is used alone in the current document but stands for "service accessibility"
and not "accessibility for all".
ETSI
10 ETSI EG 202 009-1 V1.3.1 (2014-12)
assurance (in the supplier-customer interface): knowledge and courtesy of employees and their ability to convey
trust and confidence
audit: control carried out by a third party on the compliance of a provider organization to a code of practice or a
regulation
authentication: provision of assurance of the claimed identity of an entity
NOTE: See ISO/IEC 18028-4 [i.46].
authorization: granting of permission based on authenticated identification (see ISO/IEC 7498-2 [i.39])
availability: likelihood with which the relevant components of the service function can be accessed, at the instant of
request, as required by the specified conditions, in particular those related to open hours, geographic coverage and
resource size aspects if any
NOTE: See ETSI ETR 003 [i.16] modified.
call: any connection (fixed or temporary) capable of transferring information between two or more users of a
telecommunications system. In this context a user may be a person or a machine
call set-up time: period starting when the address information required for setting up a call is received by the network
(e.g. recognized on the calling user's access line) and finishing when the called party busy tone or ringing tone or
answer signal is received by the calling party (e.g. recognized on the calling user's access line)
NOTE 1: See ETSI ETR 138 [i.17].
NOTE 2: In some standards, Post Dialling Delay (PDD) is used instead of call set-up time. (See the definition
below (ETSI TS 101 329-5 [i.32])).
capacity: ability of an item to meet a demand of a given size under given internal conditions
NOTE: In the present set of documents, the reader should have in mind that, if SLO are expected with regard to
this criterion, these SLO are the expression of a trade off between a user and the provider i.e. a
contractual commitment. If a measurement is done in this domain, it is not a QoS assessment per se but
rather a check up of the conformance to the SLO of both the use by the customer(s) and the means made
available by the provider.
certificate: certificate issued by a certification body in accordance with the conditions of its accreditation and bearing
an accreditation symbol or statement
cessation: all activities associated with the cessation of a telecommunication service from the time it was requested by a
customer, to the time it was completed to the satisfaction of the customer
charging/billing: all relevant activities associated with the charging and billing for a telecommunication service to a
customer
Charging Data Record (CDR): formatted collection of information about a chargeable event (e.g. time of call set-up,
duration of the call, amount of data transferred, etc.) for use in billing and accounting
NOTE: For each party to be charged for parts of or all charges of a chargeable event a separate CDR should be
generated, i.e. more than one CDR may be generated for a single chargeable event, e.g. because of its
long duration, or because more than one charged party is to be charged (see ETSI TR 121 905 [i.31]).
Circuit Loudness Rating (CLR): loudness loss between two electrical interfaces in a connection or circuit, each
interface terminated by its nominal impedance which may be complex
NOTE: See ETSI TR 102 008 [i.29].
connection: connection provides for transfer of information between endpoints
NOTE: See Recommendation ITU-T I.113-504 modified [i.8].
connection set up time: time between end of dialling and start of display of the first screen of a web page
ETSI
11 ETSI EG 202 009-1 V1.3.1 (2014-12)
defect: limited interruption of the ability of an item to perform a required function
NOTE 1: It may or may not lead to maintenance actions depending on the results of additional analysis.
NOTE 2: See Recommendation ITU-T I.113- 601 [i.8].
dependability (in the supplier-customer interface): the ability to provide what was promised, dependably and
accurately
digital signature: data appended to, or a cryptographic transformation of, a data unit that allows a recipient of the data
unit to prove the origin and integrity of the data unit and protect the sender and the recipient of the data unit against
forgery by third parties and sender against forgery by the recipient
NOTE: See ISO/IEC 11770-3 [i.41].
directory enquiry service: operator or machine based service intended to provide information on phone number,
addresses or e-mail addresses of people or organizations on user request
empathy (in the supplier-customer interface): degree of caring and individual attention provided to customers
encryption: (reversible) transformation of data by a cryptographic algorithm to produce ciphertext, i.e. to hide the
information content of the data
NOTE: See ISO/IEC 9797-1 [i.40].
fault: inability of an item to perform a required function, excluding that inability due to preventive maintenance, lack of
external resources, or planned actions
NOTE: See Recommendation ITU-T I.113-603 [i.8].
flexibility: ability of a service to be customized with elasticity and scalability features
NOTE: Flexibility embraces:
- Customization: options required by the customer and offered by the provider in order to
accommodate special requirements, i.e. the ability for the customer to adjust some specific features
of the subscribed service, e.g. additional features or some configuration parameters.
- Elasticity: variable resource allocation.
- Scalability: ability to size the system configuration.
function: process which conveys or transforms data in a predictable way, it may be affected by hardware, software or a
combination of the two
NOTE: See ETSI TS 102 728 [i.33].
identification: process of establishing the identity of an object or person
NOTE: See ETSI EG 201 940 [i.20].
indicator: when a metric is defined with boundaries and scope unambiguously and clearly stated this then becomes an
indicator
integrity: property of a system such that information offered at an input is delivered unchanged at an output
NOTE: See ETSI TR 101 287 [i.26].
jitter: functional description for measuring output jitter at a digital interface can be found in Recommendation
ITU-T O.172 [i.13]
KPI: metric capturing some aspects of the performance of one or more resources (including supplier resources or
services) which is measured either directly, or could be defined in hierarchies
NOTE 1: A KPI is meaningful to the SP, but not necessarily to the Customer.
NOTE 2: See TMF SLA Management Handbook.
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12 ETSI EG 202 009-1 V1.3.1 (2014-12)
KQI: metric capturing some aspects of the performance of a Service or a Product, meaningful to the Customer
NOTE 1: A KQI is typically expressed as a percentage of customers, resources or telecom entities (like a call or a
session) meeting a certain level of quality.
NOTE 2: A KQI possibly aggregates a mix of KPIs, intermediate computed components (usually from KPIs), other
KQIs (from one or even several SPs) and direct measurements, using appropriate mathematical formulas
(which are the KQI Estimators).
NOTE 3: See TMF SLA Management Handbook.
Loudness Rating (LR): objective measure of the loudness loss, i.e. a weighted, electro-acoustic loss between certain
interfaces in the telephone network
NOTE 1: If the circuit between the interfaces is subdivided into sections, the sum of the individual section LRs is
equal to the total LR. In loudness rating contexts, the subscribers are represented from a measuring point
of view by an artificial mouth and an artificial ear respectively, both being accurately specified
(Recommendation ITU-T G.111 [i.5], ETSI TR 101 329-1 [i.27]).
NOTE 2: As used in the G-Series Recommendations for planning.
Mean Opinion Score (MOS): mean of opinion scores, i.e. of the values on a predefined scale that subjects assign to
their opinion of the performance of the telephone transmission system used either for conversation or for listening to
spoken material (according to Recommendations ITU-T. P.10/G.100 [i.14] and P.800.1 [i.15])
NOTE 1: Apart from subjective opinion, the abbreviation MOS is also used for scores that originate from objective
models or network planning models. The following identifiers are recommended to be used together with
the abbreviation MOS in order to distinguish the area of application, where N refers to narrow-band,
W refers to wideband, LQ refers to Listening Quality, CQ refers to Conversational Quality, S refers to
Subjective, O refers to Objective, and E refers to Estimated.
Listening-only Conversational Talking

Subjective MOS-LQSy MOS-CQSy MOS-TQSy
Objective MOS-LQOy MOS-CQOy MOS-TQOy
Estimated MOS-LQEy MOS-CQEy MOS-TQEy

NOTE 2: The letter "y" at the end of above acronyms is a placeholder for the descriptor of the respective audio
bandwidth, see the following provisional instructions:
- N for MOS scores obtained for narrow-band (300-3 400 Hz) speech relative to a narrow-band
high quality reference. This is applicable for instance to narrow-band only subjective tests or to
P.862.1 scores.
- W for MOS scores obtained for wideband (50-7 000 Hz) speech relative to a wideband high
quality reference. This is applicable for instance to wideband only subjective tests or to P.862.2
scores.
- M for MOS scores obtained for narrow-band or wideband speech relative to a wideband high
quality reference in a mixed bandwidths context. This is applicable for instance to mixed
bandwidths subjective tests.
The effects of audio bandwidth on MOS scores are currently under investigation in ITU-T Study
Group 12. In cases where the bandwidth denominators N, W or M do not properly reflect the
actual situation, it is suggested that provisionally the placeholder "y" be replaced by a proper
notation.
NOTE 3: The MOS ranges from 1 (lowest quality) to 5 (highest quality).
metric: QoS measurement related to a particular QoS criterion
NOTE 1: Several metrics may be needed for an extensive assessment of the quality of a service with respect to a
single criterion.
NOTE 2: Several indicators may be needed to assess a single metric.
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13 ETSI EG 202 009-1 V1.3.1 (2014-12)
monitoring: use of any available technical tool to assess permanently or for a given period of time a particular QoS
indicator, e.g. a server load or the response time for a directory enquiry service
network/service management by the user/customer: all activities associated with the customer's control of predefined
changes to telecommunication services or network configurations
NOTE: See ETSI ETR 003 [i.16].
non-repudiation: ability to prove an action or event has taken place, so that this event or action cannot be repudiated
later
NOTE: See ISO/IEC 13888-1 [i.42] and ISO/IEC 7498-2 [i.39].
offer: all the service components needed for the relationship between the customer and the provider along the whole
customer relationship course
Opinion Rating (OR): quantitative value (a number) assigned to a qualitative performance criterion on a predefined
rating scale to reflect the merit of that criterion to a user/customer
NOTE: More details are available in clause 4.1 of ETSI EG 202 843 [i.23].
overall transmission quality rating (R): full acoustic-to-acoustic (mouth to ear) quality, experienced by an average
user, for a typical situation using a "standard" telephony handset
NOTE 1: The overall transmission quality rating is calculated using the E-Model (see Recommendation
ITU-T G.107 [i.3]). The relation between overall transmission quality rating (R) and user perception of
quality is defined in Recommendation ITU-T G.109 [i.4].
NOTE 2: See ETSI TR 102 276 [i.30].
performance: measure of how well a transmission system fulfils defined criteria under specified conditions
NOTE: Adapted from ETSI TR 101 830-1 [i.28].
poll: panel of a sufficient number of users or observers are asked to assess a particular QoS parameter, e.g. "Delay to
provide a draft contract"
Post Dialling Delay (PDD): time in milliseconds between dialling the last digit and an audible tone being heard at the
originating end
NOTE 1: The audible tone is typically ring-back or the engaged tone (Recommendation ITU-T E.721 [i.1],
ETSI TS 101 329-5 [i.32]).
NOTE 2: Some systems have shown to present the user with a ring-back tone before a connection has been
established, this gives the impression that the PDD is low. If the connection fails this is later switched to
an engaged tone. This is an unacceptable operation and should be tested.
provision: all activities associated with the provision of a telecommunication service, from the time of effective
contract to the time the customer is able to use the service
QoS criterion: element of a set of characteristics of a service needed for an extensive assessment of the quality of this
service
Quality of Service (QoS): collective effect of service performance which determines the degree of satisfaction of a user
of the service
NOTE 1: The quality of service is characterized by the combined aspects of service support performance, service
operability performance, serve ability performance, service security performance and other factors
specific to each service.
NOTE 2: The term "quality of service" is not used to express a degree of excellence in a comparative sense nor is it
used in a quantitative sense for technical evaluations. In these cases a qualifying adjective (modifier)
should be used.
NOTE 3: See Recommendations ITU-T E.800 [i.2] and G.1000 [i.6].
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14 ETSI EG 202 009-1 V1.3.1 (2014-12)
NOTE 4: Complementary definition on QoS requirements of the user/customer, QoS offered by service provider,
QoS achieved by service provider, QoS perceived by the user/customer are given in ETSI ETR 003 [i.16].
Quality of Service Assessment Party (QoSAP): SP internal department or an independent third party expected to
manage the QoS assessment process, to analyse the data stored by the SP, to convene an expert panel, to launch a
customer survey and to gather the results
NOTE: A QoSAP can usefully be certified by a recognized certification body.
QoS achieved by service provider: statement of the level of quality achieved by the service provider
NOTE 1: See ETSI ETR 003 [i.16] and Recommendation ITU-T G.1000 [i.6] modified.
NOTE 2: This is expressed by values assigned to indicators, which are, as far as possible, same as those for the QoS
offered. These performance figures are summarized for specified periods of time, e.g. for the previous
3 months.
EXAMPLE: The service provider may state that the achieved accessibility for a given duration (e.g. one year)
was 99,95 % or unavailable for not more than 262,8 minutes over a 365 days year.
QoS offered by service provider: statement of the level of quality expected to be offered to the user/customer by the
service provider
NOTE 1: See ETSI ETR 003 [i.16] and Recommendation ITU-T G.1000 [i.6] modified.
NOTE 2: The level of quality is expressed by values assigned to QoS indicators. These parameters are usually
designed to be understandable to the user/customer. Each service would have its own set of QoS
parameters (see ETSI ETR 003 [i.16]).
EXAMPLE: A service provider may state that the accessibility of basic telephony service is 99,9 % in a year
with not more than a 15 minutes break on any one occasion.
QoS perceived by the user/customer: statement expressing the level of quality experienced by user/customers
NOTE 1: See ETSI ETR 003 [i.16] and Recommendation ITU-T G.1000 [i.6] modified.
NOTE 2: The QoS perceived is expressed, usually in terms of degrees of satisfaction and not in technical terms.
Technical terms may be expressed where the user/customer is able to understand and use these. QoS
perceived is assessed by customer surveys and from user's/customer's own comments on levels of service.
EXAMPLE: An user/customer may state that on unacceptable number of occasions there was difficulty in
getting through the network to make a call; a satisfaction rating of 2 may be given on a 4 point
scale.
QoS requirements of the user/customer: statement of the level of quality required by the applications of
customers/users of a service, which may be expressed non-technically
NOTE 1: See Recommendation ITU-T G.1000 [i.6].
NOTE 2: These requirements may be gathered for representative groupings of users/customers. For their own use,
the service provider may translate these into technical indicators easier to manage, if needed to better
fulfil the requirements.
reliability: ability of an item to perform a required function under stated conditions for a given time period
NOTE 1: See Recommendations ITU-T E.800 [i.2] and M.60 [i.12].
NOTE 2: It is generally assumed that the item is in a state to perform this required function at the beginning of the
time interval.
NOTE 3: In French, the term fiabilité is also used to denote the performance quantified by this probability.
reliability in the supplier-customer interface: ability to provide what was promised, dependably and accurately
repair: See trouble-shooting.
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15 ETSI EG 202 009-1 V1.3.1 (2014-12)
response time for directory enquiry services: duration from the instant when the address information required for
setting up a call is received by the network (e.g. recognized on the calling user's access line) to the instant the human
operator or an equivalent voice-activated response system answers the calling user to provide the number information
requested
NOTE: See ETSI ES 202 057-1 [i.24].
response time for operator services: duration from the instant when the address information required for setting up a
call is received by the network (e.g. recognized on the calling user's access line) to the instant the human operator
answers the calling user to provide the service requested
NOTE 1: See ETSI ES 202 057-1 [i.24].
NOTE 2: Services provided wholly automatically, e.g. by voice response systems are excluded
(ETSI ETR 138 [i.17]). The services covered are the services for operator controlled and assisted calls
that are accessed with special access codes. Access to emergency services is excluded.
NOTE 3: The period in this definition includes waiting times because operators are busy, and times for going
through voice response systems to reach the operator. However it excludes the handling of the call by the
operator, e.g. conversation with the operator. The reasons are that the variety of calls to operators is too
wide and that it is too difficult/costly in practice to measure the operator's performance precisely.
responsiveness (in the supplier-customer interface): willingness to help customers and provide prompt services
sales: all relevant activities from the time communications are established between the provider and the customer to the
time the contract is signed for the provision of a service by the provider
security: ability of a service to ensure the confidentiality of the pieces
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