Bulletin

Issue: September 2004

Research in Action

Better internet services for the bush

La Trobe University is playing a major role in research designed to bring better internet services to remote rural areas.

Principal investigator, La Trobe's Dr Ben Soh, leads a team that recently won an ARC Linkage Grant to develop a new transport layer protocol to provide secure broadband internet connection via satellite to rural regions.

The team includes input from Telstra Country Wide, URSYS Pty Ltd (Sydney) and Associate Professor Dr Jean Armstrong, a former La Trobe researcher, now at Monash University. Their $161,000 grant also funds PhD student Mr Joel Sing from La Trobe, Bendigo's Information and Communication Technology Centre. In addition, Telstra is contributing access to its satellite technology.

Dr Soh, senior lecturer in La Trobe's Department of Computer Science and Computer Engineering, said satellite links were critical to connecting broadband to remote areas.

'Effective use of the internet over satellite links is essential if Business-to-Business and Business-to-Consumer E-commerce is to develop in these areas. In many application networks - particularly virtual private networks (VPN) - secure transmission is important to avoid fraud and maintain privacy. Satellite links introduce a long delay (latency) in the transmission path and existing secure internet protocols do not handle this well.'

Dr Soh said transmission control protocol (TCP) over satellite VPN was possibly the hottest research topic in the rural economy today. Combined, these two technologies had the potential to provide the best and most cost-effective 'information superhighways' in remote areas.

TCP was part of the most widely used network protocol. 'We expect the total market for satellite services provided by these technologies and the accompanied activities to be worth billions of dollars.'

Dr Soh's team aims to develop new TCP security techniques for broadband internet connections via satellite to a VPN.

Internet messages, he explained, are broken into 'packets' at the TCP layer for routing via the Internet Protocol layer to the destination address. There, the packets are reassembled at the TCP layer to recover the original messages. However, numerous problems remain.

A major one is the relatively high latency when data is transmitted. The length of the latency depends on the satellite's orbit. Geosynchronous-earth-orbit satellites have latency of about 560 milliseconds over the earth-satellite-earth link, while low-earth-orbit satellites have 10 to 20 milliseconds one-way delay, depending on the satellite's location in the sky and other factors. These delays make real time systems impossible.

Another TCP issue being investigated is a method to ensure reliable end-to-end data transmission by using 'host-based congestion control mechanisms'.

The team will present a paper on the research, TCP (Transmission Control Protocol) Performance over Geostationary Satellite Links: Problems and Solutions, at the Institute of Electrical and Electronics Engineers' International Conference on Networks in Singapore in November.•

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