ISO/IEC 13236:1998

This QOS Framework is a structured collection of concepts and their relationships which describes QOS (Quality of

Service) and enables the partitioning of, and relationships between, the topics relevant to QOS in Information

Technology (IT) to be expressed by a common means of description. In particular, this QOS Framework is directed at IT

systems and their use in providing Open Distributed Processing services.

This QOS Framework is intended to assist those designing and specifying IT systems, and those defining

communications services and protocols, by providing guidance on QOS applicable to systems, services and resources of

various kinds. It describes how QOS can be characterized, how QOS requirements can be specified, and how QOS can

be managed.

This QOS Framework defines terminology and concepts for QOS in IT. It introduces the concept of QOS characteristics,

which represent the fundamental aspects of QOS that are to be managed in various ways; and it defines a number of

QOS characteristics of particular importance. These definitions are independent of how QOS is represented or controlled

in a real system.

This Framework describes how QOS requirements can be expressed, and identifies a number of QOS mechanisms (such

as three-party negotiation) that can be used as components of QOS management functions to meet QOS requirements of

various kinds. It also describes the circumstances in which various combinations of mechanisms may be appropriate.

This QOS Framework provides a basis for the specification of extensions and enhancements to existing or planned

standards, as a result of the need for, and application of, the QOS concepts defined in this Recommendation |

International Standard. It is not the intent of this Recommendation | International Standard to destabilise any existing

Recommendations | International Standards; rather, it is intended that this QOS Framework may be used by:

· developers of new or revised IT-related standards which define or use QOS mechanisms; and

· IT users expressing requirements for QOS.

This QOS Framework does not attempt to provide a basis for the specification of performance objectives or network

signalling of QOS in public communications networks. The QOS aspects of these communications services are

addressed by other ITU-T Recommendations.

The intent of this Recommendation | International Standard is to provide a common vocabulary to both service providers

and service users. Nothing in this Recommendation | International Standard should be construed as placing requirements

on either service providers or service users. It is hoped that a common approach and vocabulary for QOS will assist

multiple service providers to deliver end-to-end QOS to end-systems.

This QOS Framework specifically excludes the detailed specification of QOS mechanisms. It is not the intent of this

Recommendation | International Standard to serve as an implementation specification, to be a basis for appraising the

conformance of implementations, or to define particular services and protocols. Rather, it provides a conceptual and

functional framework for QOS which allows independent teams of experts to work productively on the development of

Recommendations | International Standards.

As applied to OSI, this QOS Framework is consistent with the OSI Basic Reference Model in that it describes operations

and mechanisms which are assignable to layers as specified in the OSI Basic Reference Model. It is consistent with the

OSI Management Framework (see ITU-T Rec. X.700 | ISO/IEC 7498-4) and the Systems Management Overview (see

ITU-T Rec. X.701 | ISO/IEC 10040) in its assignment of functions to management entities. In Annex A, this QOS

Framework presents a model of QOS for OSI which identifies the entities that participate in the management of QOS,

defines the flow of QOS-related information between them and describes how this information is used.