Measurement-Based Admission Control: A Revisit Yuming Jiang, Peder J. Emstad, Victor Nicola * , Anne Nevin Center for Quantifiable Quality of Service in Communication Systems † Department of Telematics Norwegian University of Science and Technology ymjiang@ieee.org, {peder, nicola, anne.nevin}@q2s.ntnu.no Abstract Measurement-based admission control (MBAC) is an important technique for providing statistical service guarantees and many MBAC algorithms have been proposed in the literature. It has also been investigated in a previous work that these algorithms achieve nearly the same utilization for a given packet loss rate or in short the same loss-load curve. Based on this investigation, it has been argued that further research on better MBAC equations will likely be a fruitless endeavor since there is little room to improve existing algorithms in terms of utilization. In this paper, we investigate why the MBAC algorithms investigated in the previous work have the same loss-load curve. We find this not surprising. We hence argue that it should be other issues than the loss-load curve that should be taken into account in designing an MBAC algorithm. Based on this argument, we revisit the assumptions made by these MBAC algorithms and examine the rationales of these assumptions when these MBAC algorithms are used in different network scenarios. Finally, we discuss some remaining challenges for MBAC research. 1 Introduction Real-time multimedia applications are increasingly becoming an indispensable part of Internet traffic. These applications include voice over IP, streaming audio and video, Internet gaming and real-time video conferencing. Such applications, on the one hand, are both delay and loss sensitive and, on the other hand, can tolerate some loss and delay. As a result, statistical service guarantees have attracted a lot of research interest in the past decade. Statistical service guarantees do not provide hard loss rate or delay bound guarantees as deterministic service guarantees do. Nevertheless, for both types of service guarantees, admission control is typically required. Usually, admission control for deterministic service guarantees uses worst-case an- alytical bounds as its basis. Such admission control algorithms typically result in low * On leave from University of Twente, The Netherlands. † “Centre for Quantifiable Quality of Service in Communication Systems, Centre of Excellence”, ap- pointed by The Research Council of Norway, funded by the Research Council, NTNU and UNINETT. http://www.ntnu.no/Q2S/