POSTER 04 – EVALUATION OF BUILDING BLOCKS FOR PASSIVE ONE-WAY-DELAY MEASUREMENTS Abstract — Service Level Agreements (SLAs) specify the Quality of Services (QoS) negotiated between provider and

customer. QoS Measurements provide a suitable way to proof the fulfillment of the given guarantees. During service usage the traffic of interest is already present in the network. This traffic can be utilized for passive (non-intrusive) measurement methods avoiding the disadvantages of sending test traffic for active (intrusive) measurements. Some applications (e.g. interactive applications like IP telephony) rely on guarantees for one-way metrics like one-way delay. One-way metrics usually cannot be derived from round trip measurements. Therefore specific methods are required to measure one-way metrics. In this paper we evaluate the necessary building blocks for passive one-way-delay measurement. In particular we discuss different functions for the generation of packet identifiers needed to correlate packet arrivals at the ingress and egress measurement point. We have implemented a flexible and modular meter, which allows us to use and compare different functions for the packet ID generation. In experiments we have measured the performance of the different methods investigated in this paper. We conclude with the experiment results and identify the applicability and efficiency of the different methods. Index terms-- Passive one-way-delay measurements, IP metering, SLA validatio