Providing Internet Quality of Service based on Differentiated Services Traffic Engineering

The convergence of telecommunication systems and data networks requires services beyond what is provided as Best-Effort Service by the current Internet. For example, real-time audio and video applications have more demanding service requirements and generate traffic with significantly different properties than common web browsing or file transfer. A variety of emerging applications can be supported efficiently by the provision of certain Quality of Service parameters, like packet drop rates and delay bounds, which are critical for their performance. Thus, mechanisms have to be added to current networks that support certain service guarantees, while scaling to the size of the Internet. The most recent approach to Quality of Service of the Internet Engineering Task Force is the Differentiated Services architecture that allows for scalability by aggregating individual data flows to a small number of traffic classes for which service differentiation is provided. Nevertheless, doing so comes at a price: The multiplexing of flows to traffic aggregates creates interference that is hard to quantify, thus making the derivation of deterministic performance guarantees difficult. Services can be based on the building blocks that are defined within the Differentiated Services framework, but at the end, it is the composition of the traffic aggregates that is essential for the achieved performance. Any flow that is added to a traffic aggregate can deteriorate the offered service. Therefore, a careful admission control that provides access to services is of major importance…