Abstract.Internet is widely known for lacking any kind of mechanism for the provisioning of Quality of Service (QoS) guarantees. The Internet community currently concentrates its efforts on mechanisms that support QoS in various layers of the OSI model. Apart from that, the Internet community is trying also to define the protocols, through which applications and users will signal their QoS requirements to the lower network layer mechanisms. The latter task, however, is not trivial, especially for legacy applications that cannot be modified and recompiled. This paper presents a framework for a middleware component that supports QoS for legacy applications. It mainly focuses on the support of a proxy-based framework for the identification of flows, the measurement of basic QoS parameters and the definition of an API that can be used by middleware components or even applications. The position of this proxy architecture in a reference network topology and the communication with other middleware entities is also discussed.

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SUMMARYThe support of quality of service (QoS) in the Internet has become one of the most important topics within the Internet community. The introduction of the Integrated Services (IntServ) and the Differentiated Services (DiffServ) architectures was a major breakthrough in this direction. Enhanced by the Bandwidth Broker concept, DiffServ aims to provide QoS in the Internet through the prioritization of some IP flows over others. However, up to now the DiffServ architecture lacks a standard mechanism for the interaction between users/applications and the Bandwidth Brokers (BB), so that end-to-end QoS can be achieved.In this paper we present a distributed middleware architecture for the transparent support of QoS in the Internet. The paper focuses on bridging the gap that currently exists between applications and the network and presents the end-user application toolkit (EAT). The EAT middleware provides a framework for the presentation of network services to users, the description and selection of QoS parameters, the forwarding of reservation requests and the verification of the accredited QoS level. Through the concept of application profiles, it aims to support QoS for legacy applications, that is, commercial applications that cannot be modified to support QoS.