ISO/IEC TS 25052-1:2022

Systems and software engineering - Systems and software Quality Requirements and Evaluation (SQuaRE): cloud services - Part 1: Quality model

This document defines the quality model of cloud services. The quality model of cloud services is composed of nine characteristics (some of which are further subdivided into subcharacteristics), which provide consistent terminology for specifying, measuring and evaluating cloud services so that the stakeholders, cloud service customer (CSC), cloud service provider (CSP) and cloud service partner (CSN) have a common understanding. Since the quality model in this document is the extension to the existing quality models defined in ISO/IEC 2501n, it can be used with the product quality model, IT service quality model, data quality model, and quality-in-use model according to evaluation purposes. As there are several cloud service categories, this document focuses on the quality model of SaaS (Software as a Service). NOTE Future documents are intended to address PaaS (Platform as a Service) and IaaS (Infrastructure as a Service).

Ingénierie des systèmes et du logiciel — Exigences de qualité et évaluation des systèmes et du logiciel (SQuaRE): services en nuage — Partie 1: Modèles de qualité

General Information

• Status: Published
• Publication Date: 10-Jul-2022
• ICS: 35.080 - Software
• Technical Committee: ISO/IEC JTC 1/SC 7 - Software and systems engineering
• Drafting Committee: ISO/IEC JTC 1/SC 7 - Software and systems engineering
• Current Stage: 9060 - Close of review
• Completion Date: 04-Mar-2029

Overview

ISO/IEC TS 25052-1:2022 specifies a quality model for cloud services as part of the SQuaRE (Systems and software Quality Requirements and Evaluation) family. The technical specification defines a consistent terminology and structure for specifying, measuring and evaluating non‑functional aspects of cloud services - with a current focus on SaaS (Software as a Service). It is intended to be used by cloud service customers (CSC), cloud service providers (CSP) and cloud service partners (CSN) to align expectations, requirements and evaluations, and to support SLA definition and compliance.

Key topics and technical requirements

• Quality model framework: Extension to the ISO/IEC 2501n quality models so cloud-specific characteristics can be combined with product, IT service, data and quality‑in‑use models.
• Nine cloud quality characteristics: The document defines nine high‑level characteristics (some with subcharacteristics). Examples included in the text:
  • Service performance efficiency (subcharacteristics: time‑behaviour, aggregated resource utilization, capacity, scalability, elasticity)
  • Service compatibility (including cloud interoperability)
  • Service usability (including accessibility for diverse client devices)
  • Service reliability (including availability, resilience, recoverability)
  • Service security (including confidentiality)
• Cloud-specific considerations: Addresses cloud traits such as broad network access, measured service, multi‑tenancy, on‑demand self‑service, rapid elasticity and resource pooling - and their impact on quality measurement.
• SLA linkage: Emphasizes parameters and measures that feed into Service Level Agreements (SLA), e.g., capacity limits, response times, availability targets.
• Terminology and measurement readiness: Provides consistent definitions to enable specification of measurable quality requirements and evaluation modules.

Applications and users

This standard is practical for:

• Cloud service customers and procurers: Defining selection criteria, acceptance tests and SLAs for SaaS.
• Cloud service providers: Designing, testing and reporting service quality; aligning offerings to measurable quality characteristics.
• Architects and developers: Translating non‑functional requirements (scalability, elasticity, interoperability) into design and test goals.
• QA teams and auditors: Establishing evaluation metrics, quality control criteria and audit evidence for cloud services.
• Partners and integrators: Assessing compatibility and interoperability when integrating multiple cloud services.

Common use cases: cloud service selection, requirements analysis, SLA drafting, development/test objective setting, operational monitoring, and audit/evaluation.

Related standards

• ISO/IEC 25000 (SQuaRE guide and quality models)
• ISO/IEC 22123-1 (cloud computing vocabulary)
• ISO/IEC 17788 (cloud computing concepts)
• ISO/IEC 19086 (SLA framework)

Keywords: ISO/IEC TS 25052-1:2022, SQuaRE, cloud services quality model, SaaS quality model, cloud service evaluation, cloud SLA, cloud interoperability, service performance, service reliability, service security.

Standards Content (Sample)

TECHNICAL ISO/IEC TS
SPECIFICATION 25052-1
First edition
2022-07
Systems and software engineering —
Systems and software Quality
Requirements and Evaluation
(SQuaRE): cloud services —
Part 1:
Quality model
Ingénierie des systèmes et du logiciel — Exigences de qualité et
évaluation des systèmes et du logiciel (SQuaRE): services en nuage —
Partie 1: Modèles de qualité
Reference number
© ISO/IEC 2022
© ISO/IEC 2022
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
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ISO copyright office
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Published in Switzerland
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© ISO/IEC 2022 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 S c op e . 1
2 Nor m at i ve r ef er enc e s . 1
3 Terms and definitions . 1
3.1 Q uality model of cloud services . . 1
3.2 T erms relating to software quality . 6
3.3 T erms relating to cloud computing . 7
4 Abbr ev i at ed t er m s . 9
5 Quality model framework .9
5 .1 O ver v iew . 9
5.2 R elationships between quality model of cloud services and other quality models . 10
5.3 Q uality model of cloud services . . 11
Annex A (informative) Original source of characteristics of quality model .13
Bibliography .15
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© ISO/IEC 2022 – All rights reserved

Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are
members of ISO or IEC participate in the development of International Standards through technical
committees established by the respective organization to deal with particular fields of technical
activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international
organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the
work.
The procedures used to develop this document and those intended for its further maintenance
are described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria
needed for the different types of document should be noted. This document was drafted in
accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives or
www.iec.ch/members_experts/refdocs).
Attention is drawn to the possibility that some of the elements of this document may be the subject
of patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent
rights. Details of any patent rights identified during the development of the document will be in the
Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents) or the IEC
list of patent declarations received (see https://patents.iec.ch).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see
www.iso.org/iso/foreword.html. In the IEC, see www.iec.ch/understanding-standards.
This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 7, Software and systems engineering.
A list of all parts in the ISO/IEC TS 25052 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards
body. A complete listing of these bodies can be found at www.iso.org/members.html and
www.iec.ch/national-committees.
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© ISO/IEC 2022 – All rights reserved

Introduction
In the SQuaRE series, there are well-defined quality models for measuring and evaluating system and
software products, IT services, data, etc. Although the SQuaRE series provides practical quality models,
it does not fit new technologies well. To support the evaluation of new technologies, this document
provides the quality model of cloud services, which is the extension to the quality models defined in
ISO/IEC 2501n. In order to provide a practical guideline for quality evaluation of cloud services, this
document has reflected special considerations on cloud computing, which are key characteristics,
and cross-cutting aspects described in ISO/IEC 17788, and service level agreement (SLA) framework
described in ISO/IEC 19086 (all parts).
Compared to the information and communication technology (ICT) systems, cloud computing has
different characteristics. The followings are the key characteristics of cloud computing described in
ISO/IEC 17788.
— Broad network access: physical or virtual resources are available when needed through the network
using a variety of client devices.
— Measured service: resources are measured and paid for on a usage basis.
— Multi-tenancy: physical and virtual resources are allocated to multiple tenants, and their
computations and data are isolated, therefore inaccessible from one another.
— On-demand self-service: cloud services are provisioned by cloud service customers automatically or
with minimal interaction with cloud service providers.
— Rapid elasticity and scalability: resources are increased or decreased rapidly and elastically, and
scalable horizontally and vertically.
— Resource pooling: physical or virtual resources are aggregated to provide services to one or more
cloud service customers.
The quality model in this document is to support the non-functional specification and evaluation of cloud
services from different perspectives by those associated with cloud service selection, requirements
analysis, development, use, evaluation, support, maintenance, quality assurance and control, and audit.
For example, activities during cloud service selection that can benefit from the use of the quality model
include:
— identifying cloud services requirements;
— establishing cloud service selection criteria;
— defining service coverage and service objectives;
— establishing service level agreements;
— establishing measures of quality characteristics in support of these activities.
Activities during cloud service development that can benefit from the use of the quality model include:
— identifying cloud service requirements;
— validating comprehensiveness of requirement definitions;
— identifying cloud service design objectives;
— identifying cloud service testing objectives;
— identifying quality control criteria as part of quality assurance;
— identifying acceptance criteria for a cloud service;
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© ISO/IEC 2022 – All rights reserved

— establishing measures of quality characteristics in support of these activities.
Figure 1 (adapted from ISO/IEC 25000) illustrates the organization of the SQuaRE series representing
families of standards, further called divisions. This document belongs to extension division 25050 to
25099.
Figure 1 — Organization of the SQuaRE series of International Standards
The divisions within the SQuaRE series are:
— ISO/IEC 2500n - Quality management division. The International Standards that form this division
define all common models, terms and definitions further referred to by all other International
Standards from the SQuaRE series. The division also provides requirements and guidance for a
supporting function that is responsible for the management of the requirements, specification and
evaluation of software product quality.
— ISO/IEC 2501n - Quality model division. The International Standards that form this division
present detailed quality models for computer systems and software products, quality in use, and
data. Practical guidance on the use of the quality models is also provided.
— ISO/IEC 2502n - Quality measurement division. The International Standards that form this
division include a quality model framework, mathematical definitions of quality measures, and
practical guidance for their application. Examples are given of quality measures for software
quality, and measures for quality in use. Quality measure elements (QME) forming foundations for
these measures are defined and presented.
— ISO/IEC 2503n - Quality requirements division. The International Standards that form this
division help specify quality requirements, based on quality models and quality measures. These
quality requirements can be used in the process of quality requirements elicitation for a software
product to be developed or as input for an evaluation process.
— ISO/IEC 2504n - Quality evaluation division. The International Standards that form this division
provide requirements, recommendations and guidelines for software product evaluation, which are
performed by evaluators, acquirers or developers. The support for documenting a measure as an
evaluation module is also presented.
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— ISO/IEC 25050 to ISO/IEC 25099 - SQuaRE extension division. This division includes International
Standards specifying requirements for quality of ready to use software product and common
industry formats for usability reports, as well as this document.
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© ISO/IEC 2022 – All rights reserved

TECHNICAL SPECIFICATION ISO/IEC TS 25052-1:2022(E)
Systems and software engineering — Systems and software
Quality Requirements and Evaluation (SQuaRE): cloud
services —
Part 1:
Quality model
1 S cope
This document defines the quality model of cloud services.
The quality model of cloud services is composed of nine characteristics (some of which are further
subdivided into subcharacteristics), which provide consistent terminology for specifying, measuring
and evaluating cloud services so that the stakeholders, cloud service customer (CSC), cloud service
provider (CSP) and cloud service partner (CSN) have a common understanding.
Since the quality model in this document is the extension to the existing quality models defined in
ISO/IEC 2501n, it can be used with the product quality model, IT service quality model, data quality
model, and quality-in-use model according to evaluation purposes. As there are several cloud service
categories, this document focuses on the quality model of SaaS (Software as a Service).
NOTE Future documents are intended to address PaaS (Platform as a Service) and IaaS (Infrastructure as a
Service).
2 Normat ive references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 25000, Systems and software engineering — Systems and software Quality Requirements and
Evaluation (SQuaRE) — Guide to SQuaRE
ISO/IEC 22123-1, Information technology — Cloud computing — Part 1: Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 25000, ISO/IEC 22123-1,
and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1 Quality model of cl oud services
3.1.1
service performance efficiency
degree to which a cloud service meets performance requirements under stated conditions
© ISO/IEC 2022 – All rights reserved

3.1.1.1
time-behaviour
degree to which a cloud service meets the requirements of the response times and throughput rates of
a cloud service, when concurrent users take advantage of the cloud service
[SOURCE: ISO/IEC 25010:2011, 4.2.2.1, modified — “a cloud service meets the requirements of” has
been added, “a product or system” has been replaced by “a cloud service” and “when performing its
functions, meet requirements” by “when concurrent users take advantage of the cloud service”]
3.1.1.2
aggregated resource utilization
degree to which a cloud service utilizes efficiently aggregated resources from resource pooling in order
to support multi-tenancy
Note 1 to entry: Resource pooling is the feature where physical or virtual resources can be aggregated to provide
a cloud service to one or more cloud service customers.
Note 2 to entry: Resources include CPU, memory, disk and network.
3.1.1.3
capacity
degree to which the maximum limits of a cloud service’s parameters meet requirements in SLA (Service
Level Agreement)
Note 1 to entry: Parameters can include the limit of simultaneous cloud service connections, the limit of available
cloud service resources, cloud service throughput and cloud service bandwidth.
[SOURCE: ISO/IEC 25010:2011, 4.2.2.3, modified — “a product or system parameter” has been replaced
by “a cloud service's parameters” and “in SLA (Service Level Agreement)” has been added]
3.1.1.4
scalability
degree to which physical and virtual resources are available automatically and immediately, when they
are needed, subject to constraints of service agreements
3.1.1.5
elasticity
degree to which a cloud service adjusts rapidly and elastically the amount of resources that are allocated
to an instance of the service
3.1.2
service compatibility
degree to which a cloud service can exchange information with CSC’s systems or other cloud services
and/or perform its required functions
[SOURCE: ISO/IEC 25010:2011, 4.2.3, modified- “a product, system or component” has been replaced
by “a cloud service” and “other products, systems or components” by “CSC’s systems or other cloud
services”, and “while sharing the same hardware or software environment” has been deleted.]
3.1.2.1
cloud interoperability
degree to which a cloud service interacts with CSC's systems, or interacts with other cloud services, by
exchanging information according to a prescribed method to obtain predictable results
[SOURCE: ISO/IEC 22123-1: 2021, 3.7.2, modified — “ability of a CSC’s system to interact with a cloud
service, or the ability for one cloud service to interact” has been replaced by “degree to which a cloud
service interacts with CSC's systems, or interacts”]
© ISO/IEC 2022 – All rights reserved

3.1.3
service usability
degree to which a cloud service can be used by specified users to achieve specified goals with
effectiveness, efficiency and satisfaction in a specified context of use
[SOURCE: ISO/IEC 25010:2011, 4.2.4, modified — “a product or system” has been replaced by “a cloud
service”]
3.1.3.1
accessibility
degree to which a cloud service can be accessed by a variety of client devices over a network through
standard mechanisms
3.1.4
service reliability
degree to which a cloud service performs specified functions under specified conditions for a specified
period of time
[SOURCE: ISO/IEC 25010:2011, 4.2.5, modified — “a system, product or component” has been replaced
by “a cloud service”]
3.1.4.1
availability
degree to which a cloud service is accessible and usable upon demand by an authorized entity
[SOURCE: ISO/IEC 22123-1: 2021, 3.14.7, modified — “property of being” has been replaced by “degree
to which a cloud service is”]
3.1.4.2
resilience
degree to which a cloud service recovers operational condition quickly after a fault occurs
[SOURCE: ISO/IEC 19086-1:2016, 3.19, modified — “ability of” has been replaced by “degree to which”]
3.1.4.3
recoverability
degree to which a cloud service supports its critical business functions to an acceptable level within a
predetermined period of time following a disaster
[SOURCE: ISO/IEC 19086-1:2016, 3.7, modified — “ability of the ICT elements of an organization to
support” has been replaced by “degree to which a cloud service supports”]
3.1.5
service security
degree to which a cloud service protects information and data so that persons or other products or
systems have the degree of data access appropriate to their types and levels of authorization
[SOURCE: ISO/IEC 25010:2011, 4.2.6, modified — “a product or system” has been replaced by “a cloud
service”]
3.1.5.1
confidentiality
degree to which a cloud service ensures that data are accessible only to those authorized to have access
[SOURCE: ISO/IEC 25010:2011, 4.2.6.1, modified — “a product or system” has been replaced by “a cloud
service”]
3.1.5.2
accountability
degree to which the actions of an entity can be traced back uniquely to the entity
[SOURCE: ISO/IEC 25010:2011, 4.2.6.4 — “back” has been added]
© ISO/IEC 2022 – All rights reserved

3.1.5.3
isolation
degree to which computations and data of a cloud service are isolated from and inaccessible to one
another in the situation that physical and virtual resources are shared by multi-tenants
3.1.5.4
PII protection conformance
personally identifiable information protection conformance
degree to which a cloud service conforms to the standards, laws, or regulations applied to collection,
processing and disposal of PII (personally identifiable informat
...