Analysis and Rating of QoS Approaches for E-Service Infrastructures

Implementing e-services successfully requires an adequate service infrastructure which delivers a solid base for reliable services. A major part of this service infrastructure is the transport infrastructure which e.g. constitutes the Internet. This transport infrastructure is responsible for delivering a reliable end to end transport service with different service levels which is a prerequisite for any e-service built on top of it. Current approaches concerning the provision of QoS for end to end services in the Internet concentrate on the network layer. QoS characteristics, resulting from a top down analysis, which are needed by current and future e-services were not the primary design goal of these approaches. The ATM technology was designed with the top down analysis in mind. Therefore it is a solid base for building a QoS infrastructure. However ATM is currently only used for some parts of the Internet and therefore it is not able to provide an end to end service in common. Hence end to end QoS provision must be solved by the network layer. The criteria to analyse the capabilities can be derived from a combination of general QoS parameters defined by ITU-T and the concrete QoS concepts of ATM. The evaluation of two state of the art QoS provision technologies of the network layer, Differentiated Services and Integrated Services, is carried out by the application of the developed criteria catalog. As the main result we present the comparison of the scenario independent ratings of Differentiated Services and Integrated Services.