Intersil promises to double 802.11g throughput

Intersil has developed a way to turbo-charge 802.11g wireless Lan hardware operating in a mixed network with older 802.11b...

Semiconductor company, Intersil has developed a way to turbo-charge 802.11g wireless Lan hardware operating in a mixed network with older 802.11b hardware.

Though 802.11g has a raw data rate of 54Mbit/sec, the final draft of the 802.11g standard approved by the IEEE provides for actual data rates of 10Mbit/sec when 802.11g clients operate in a mixed network with 802.11b clients. Both standards operate in the same 2.4GHz frequency band.

Joe Zyren, the company's director of strategic marketing, said Intersil has developed a non-proprietary firmware upgrade called Nitro that will boost throughput of 802.11g hardware in a mixed network to 20Mbit/sec.

Nitro, which Intersil would like to see incorporated in the IEEE 802.11e standard that governs WLan quality of service, will boost throughput by allowing 802.11g devices to transmit six times more packets than normal before having to transmit a "clear to send signal" command to 802.11b clients in the network. 

Sheung Li, a product marketing manager at Atheros Communications, said the protection schemes built into the draft 802.11g standards cause the slowdown in 802.11g throughput in mixed networks.

Zyren said by the lower data rates in mixed networks resulted from the need to accommodate "b" clients, which operate at an actual date rate of about 5Mbit/sec. 

"The 'b' clients are what slow the network down," and not the protection scheme, Zyren said. 

Leigh Chinitz, chief technology officer in the wireless Lan division of Proxim, said that the slower speeds for 802.11g clients in a mixed network results from the IEEE's desire to insure interoperability between "b" and "g" hardware. 

Proxim has developed a dual-slot access point that contains both "b" and "g" cards, allowing users to maximise data rates with both standards.

The "b" and "g" standards both have three non-overlapping channels in the 2.4GHz band, and enterprises can configure a network using a dual-slot access point that allocates one non-overlapping channel to the "g" standard and another to the "b" standard. 

Alan Reiter, an analyst at Wireless Internet & Mobile Computing, said the sharp contrast between raw data rates and actual throughput for 802.11g illustrates a problem rife in the wireless data industry.

The industry, as well as cellular carriers, "quote raw, theoretical data rates that are absolutely misleading", said Reiter. 

He urged the industry to clearly offer true data rates in packages, product literature and advertisements.

Bob Brewin writes for Computerworld

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