Architectures for the modelling of QoS functionality

摘要

The operational part of the OSI and ISDN QoS frameworks comprises: 1. A static structure of entities performing traffic handling functions; 2. QoS-related parameters, and 3. QoS-services. With this as a basis, some modifications as well as new aspects have been proposed. Within this paper, the QoS parameters have been classified as QoS requirement parameters (Q-parameters) and traffic flow parameters (F-parame-ters). The proposed solution is based on an application-oriented QoS-service formally defined by layered traffic contracts, consisting of a negotiated set of Q-and F-parameters. Time-regions are made visible as a dimension in the characterisation of Q-parameters, F-parameters and traffic handling functionality. A telecommunication service providing system shall satisfy the requirements of the applications. A QoS architecture based on an application-oriented flow classification of the total layered functionality seems therefore to be the appropriate choice. This will conserve knowledge about the application Q- and F-parameters. By avoiding multiplexing above the link layer, QoS-related co-operation between the layers is made possible. Such a solution gives a flexible and flow-harmonised architecture.