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Date:  Tue, November 19, 2013
Time:  1:00 pm
Location:  Holmes Hall 389
Speaker:  Professor Ulrich Speidel, Department of Computer Science, University of Auckland

 Abstract:
Real-time applications on the Internet include everyday applications such as Voice over IP telephony, but also more advanced technologies such as remote manipulation, e.g., for remote surgery. These applications work best if their packet trains arrive with minimum latency, low packet loss, constant inter-arrival times and all packets in the order in which they were transmitted. Latency is largely unavoidable due to the physical distance, but not meeting the remaining requirements perfectly requires applications to buffer packets until sufficient data for meaningful processing (e.g., audio playback) has accumulated at the receiver.
Conventional "improvements" to Internet infrastructure, such as the addition of new links and load balancing can be a double-edged sword: While they create extra bandwidth and reduce congestion and sometimes latency, they also create additional router queues and alternative paths, potentially affecting inter-arrival times and in-order delivery. This is in particular a problem if the destination is served by long thin networks. Our project is a longitudinal study that attempts to track the long-term global trend in the arrival quality of real-time long distance packet streams.

Biography:
Ulrich Speidel is a Senior Lecturer in the Department of Computer Science at the University of Auckland. His academic credentials include studies in Germany, and MSc in Physics from the University of Auckland, and a PhD in Computer Science from the University of Auckland in 1998. His interests and experiences are diverse, including signal processing, T-codes, underwater acoustics, technology consulting, information theory, JavaScript, and book translations. A current interest is accurate measurement of packet transit times across the Internet in support of real-time and delay-sensitive applications.