A framework for testing IP QoS over ATM networks: implementation and practical experiences

Driven by increasing competition, service providers target customers to deliver value added IP services like "voice over IP" (VoIP) or "virtual private networks" (VPN) over their networks. Thus, IP has become the de facto convergence layer which integrates all types of traffic within a heterogeneous network infrastructure. On the one hand IP was originally designed for best effort networks. On the other hand many new applications rely on a pre-specified end-to-end quality of service (QoS) with statistical guarantees on delay and loss. In this context the question arises, how will the quality of IP flows be evaluated? It is shown that a modular approach is highly efficient to test QoS parameters and mechanisms. This paper describes the principles of a modular testing system implemented at GMD FOKUS and presents the results of practical experiments. The first part of the paper introduces the architecture of a modular testing system and details current research activities to set up a framework for testing IP QoS over ATM networks. The second part discusses different methods to measure QoS parameters in an ATM network environment. The third part presents results of current experiments concerning developments for IP QoS testing. Thus the paper gives an overview on the entire cycle of QoS measurements: from test configurations via necessary test functionalities to the presentation of test results.