Linux powers nation's largest satellite network

Some 75 towns across New South Wales have started accessing the Internet through Linux-based satellite routers in what is said to be largest network of its type in Australia spanning upwards of 800,000 square kilometres.

The Rural Link project by was initiated four years ago when the State Library of NSW approached the federal government about connecting country libraries in NSW to the Internet via satellite due to the expense of ISDN.

map of Rural Link satellite network coverage

The project's principal coordinator, Charles Jago, said the network is unique due to its size and varied nature of each access point. Jago, who said he was unaware of others doing satellite and wireless to this extent, added, "There are now connections to 180 buildings [across the 75 towns] all over NSW."

After experimenting with two-way satellite communication, the decision was made to implement a one-way satellite download combined with ISDN back haul and 802.11b Wi-Fi for wireless access through the towns.

"Web traffic doesn't mix well with two-way satellite due to latency and by mid-2003 the rollout was sped up," Jago told Computerworld.

"Wi-Fi is fine but every town needed to be done differently due to local trees and valleys. Also, our intention is to use satellite in places that don't have broadband or DSL which has been a moving target."

The Rural Link network is intended for country community groups, health facilities and council and community technology centres and is separate to the federal government's $250 million broadband rollout to the state's public schools. Close to $4.5 million has been spent on the Rural Link network with primary funding of $3.99 million coming from Networking the Nation funds, and additional backing from the NSW Office of ICT, and BHP Billiton. Of the 75 access points about 16 are without Wi-Fi. Both Telstra and local satellite router developer Ursys won the contract to build the network.

"I have good technical people doing a lot of kilometres," Jago said. "Telstra sources the satellite dish and the Linux-based Ursys BusiBox satellite router interfaces with ISDN."

Jago described the BusiBox as a reliable and secure product and said the outcome "has been good".

The satellite data service costs $3500 per month for 1GB per month and can be shared between 12 to 20 people for "normal" Web access.

"Since going live this year the response from the towns has been good," he said. "We are now doing questionnaires for feedback. The towns have been very helpful with our work."

Ursys' managing director, Grahame Cover, said the company started in response to Telstra's introduction of satellite services.

"In 1999 when Telstra began its satellite service we used routers from the US but they were unsatisfactory for Australian conditions," Cover said. "We also tried to develop an interface with Windows but got too frustrated as [we found it] too unstable."

Ursys routers use Debian GNU/Linux as the base operating system and developed a networking application suite for it in Sydney.

"We source a variety of Intel, VIA, and National Semiconductor hardware and have developed our own TCP/IP stack as standard [TCP/IP] doesn't function well with satellite," he said. "We also use open source software for other applications like firewalls, QoS, IPSec VPNs, mail and DNS. All management is done via a Web interface so the client doesn't see the Linux interface."

Ursys chose Debian because of its packaging support, which facilitates the ability to push updates to the routers remotely.

"We have three experienced Linux maintainers and a lot of our work has been pushed back into open source," Cover said. "Some satellite software is proprietary but our IP lies in our package and integration work."

The Rural Link network uses the diskless BusiBox routers, which can be solar-powered.

"Some solar regulators have weird power regulators so we had to build our own," he said. "We're now integrating voice for voice over satellite which is difficult. We have balanced the latency and taken out the echo. Industries like mining want to run phones across satellite links."

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