Navy prepares wireless LAN for testing at sea

The 40 wireless gateways on the USS Howard let the Navy extend its data reach to 'the last 100 feet, where the work gets done,' SmartShip science and technology manager David Bartlett says.

The Navy this month will begin the final tests of a wireless shipboard network that service brass expect will lead to the use of such LANs across the fleet.

The service outfitted a new destroyer, the USS Howard, with a wireless LAN for this last evaluation leg of its SmartShip program. Forty wireless gateways from 3e Technologies International Inc. of Rockville, Md., extend Ethernet connectivity from the Howard's asynchronous transfer mode backbone.

'With the [wired] network, we're restricted to the nearest LAN drop,' said David Bartlett, the Navy's SmartShip science and technology manager. 'With the gateways, we get to the last 100 feet, where the work gets done.'

The Navy installed the 3e-520N gateways in January for a final evaluation phase before the service approves wireless technology for use fleetwide. The first feasibility studies and lab tests began about two years ago.

'We've done the paper studies. Now, we have to find out how a crew can actually use it and establish metrics,' Bartlett said.

The SmartShip program, an effort to reduce crew requirements by automating shipboard operations, already has high-speed fiber networks available on many ships for monitoring and control functions. Wireless gateways will increase network range.

'The new generation of sailors grew up with computers,' Bartlett said. 'They expect this capability, and we need this technology.'
The Howard, an Arleigh Burke-class destroyer commissioned last October in Galveston, Texas, has been to sea but the Navy is finishing its outfitting. The ship will return to sea at the end of the month to test the wireless LAN. Since Sept. 11, ships available to test new technology are in short supply.

'The Howard is a full-blown Navy ship, but it's not being deployed yet with a battle group, so we're taking full advantage of it while we can,' Bartlett said.

The 3e-520N gateways support both infrared and IEEE 802.11b wireless connectivity. Sailors can use notebook computers with wireless network interface cards, personal digital assistants or other types of handheld devices.

All the gateways have Geode SC3200 single-chip processors from National Semiconductor Corp. of Santa Clara, Calif. The 802.11b gateways follow the Wired Equivalent Privacy protocol, whose security has been criticized for weak key exchange.
'We are augmenting that' to improve security, said Benga Erinle, 3e Technologies' director of government operations.

Necessary slowness

The gateways filter devices' media access control addresses in wireless NICs and also support virtual private networking with Triple Data Encryption Standard encryption.

Encryption'either on the gateway or in a VPN'slows throughput, but 'the Navy has accepted that as a fact of life,' Erinle said.

The Howard's gateways operate at about 4.8 Mbps, about half the standard 10-Mbps Ethernet rate.

On the other hand, radio frequency leakage is minimal, Erinle said. 'The signals are barely discernible off the ship,' he said. The ship's metal construction does not seem to cause problems.

'While there is a lot of metal, there are a lot of holes to run cable, and radio waves find a way to penetrate them,' he said. 'The metal in the bulkheads acts as a wave guide, so it's a surprisingly good environment.'

About the Author

William Jackson is a Maryland-based freelance writer.

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