Dominik Kaspar successfully defended his PhD
On Wednesday 11
January, Dominik Kaspar defended his PhD thesis Multipath Aggregation of Heterogeneous Access Networks. The defense took place in the Storstua auditorium at Simula Research
Laboratory.
In his thesis, Dominik Kaspar explores different ways to increase the speed and reliability of Internet connections by transmitting data over several networks simultaneously. One of the proposed solutions, which can be used by Web browsers and other HTTP-based applications, resulted in a U.S. patent. This method uses logical file segmentation and request pipelining to split a file over numerous Internet paths and recombine it at the destination. Experiments with live video streaming showed that this approach is highly efficient and can be deployed in a lightweight manner.
Furthermore, the thesis investigates the negative effects of data reordering. When data packets are sent over several Internet connections that differ in speed, the packets are likely to arrive out of order. Especially for the TCP communication protocol, which transports the majority of Internet traffic, packet reordering is known to be very destructive. To reduce packet reordering, a scheduler was designed that keeps track of the connection speeds and smartly sends packets so that they always arrive in order at the destination. In addition, a large set of experiments was carried out in which TCP was exposed to various degrees of packet reordering. Thereby, several parameters were identified, which, when correctly tuned, lead to improved TCP performance over multiple networks.
While related research often introduces complexity to third-party servers or to long-established network protocols, the proposed solutions target an easy deployment. Implemented and tested in real-world networks, the thesis shows the benefit of simultaneously using multiple Internet connections to achieve a higher data throughput.
The thesis is written within the field of computer networks. The work has been conducted at Simula Research Laboratory and Telenor ASA.
Prior to the defense, at 10:15, Dominik Kaspar presented his trial lecture Software Defined Networking: will OpenFlow change the computer networks?
The adjudication committee
- Professor Anna Brunström, Computer Science Department, Karlstad University
- Professor Olivier Bonaventure, Department of Computing Science and Engineering, Université Catholique de Louvain
- Professor Michael Welzl, Department of Informatics, University of Oslo
Chair of the disputation
Morten Dæhlen, University of Oslo
Supervisors
- Professor Paal E. Engelstad, Telenor ASA
- Dr. Audun F. Hansen, Simula Research Laboratory
- Professor Carsten Griwodz, Simula Research Laboratory & University of Oslo
- Professor Pål Halvorsen, Simula Research Laboratory & University of Oslo
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