We have worked on "best possible" and "practical" traffic characterizations for deterministic quality-of-service. We have studied a lot of MPEG video traces and looked at fast and accurate characterization methods for MPEG.

D.E. Wrege, E.W. Knightly, H. Zhang, and J. Liebeherr, "Deterministic Delay Bounds for VBR Video in Packet-Switching Networks: Fundamental Limits and Practical Tradeoffs", IEEE/ACM Transactions on Networking, Vol. 4, No. 3, pp. 352 - 362, June 1996. (postscript).
D.E. Wrege and J. Liebeherr, "Video Traffic Characterization for Multimedia Networks with a Deterministic Service", Proc. IEEE Infocom '96,, pp. 537-544, March 1996, San Francisco. (postscript).

Packet Scheduling

We have developed and proved exact admission control tests for Earliest- Deadline-First (EDF) and Static Priority (SP). These results were the first exact admission control tests available for general traffic characterizations.

We have proposed a new packet scheduler, called Rotating Priority Queues (RPQ). RPQ schedulers are built with FIFO queues, which are rotated after fixed time periods. We have showed that, at 155 Mbps, an RPQ video multiplexer with only 10 FIFO queues can support as many MPEG video streams as an EDF multiplexer. Recently, we proposed RPQ+, which overcomes some pathologies of RPQ.

J. Liebeherr, D.E. Wrege, and D. Ferrari, Exact Admission Control in Networks with Bounded Delay Sevices, to appear: IEEE/ACM Transactions on Networking, October 1996. (postscript).
D.E. Wrege and J. Liebeherr, "A Near-Optimal Packet Scheduler for QoS Networks", June 1996, submitted. (postscript).
J. Liebeherr and D. E. Wrege. "An Efficient Solution to Traffic Characterization of VBR Video in Quality-of-Service Networks", submitted. (postscript).

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