Supporting QoS for legacy applications

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.