Meru Fixes Mixed Mode

By Eric Griffith

August 10, 2004

The WLAN switch vendor says its new access point will deliver full 802.11g performance even in the presence of 802.11b clients notorious for cutting throughput.

In the last quarter of this year, Meru Networks of Sunnyvale, Calif. says it will ship a new access point that, when coupled with the Meru Air Traffic Control system, will allow full performance of 802.11g and 11b clients running simultaneously in a mixed-mode network.

Because of the well documented problems that 11g clients have running at top speed due to the extra overhead needed for backwards compatibility when an 11b client is introduced into a network, "enterprise customers only get an incremental bandwidth increase going from b to g," says Kamal Anand, vice president of marketing at Meru. 802.11b has a datarate of 11Mbps (real world around 6Mbps), while 802.11g is rated for 54Mbps (real world of around 25Mbps). But put the two together, and 11g speeds can drop by 50% or more.

Anand says the problem is analogous to that of 10/100Mbps Ethernet networks, where if there are 10Mb and 100Mb lines on different ports, the 100Mb clients get the same performance as the 10Mb clients.

"They suffer because there's one slow client in the mix," he says.

The new access point, the AP200, will come with two radios which can be programmed to support either the 2.4GHz band (used by 802.11b & g) or the 5GHz band (used by 802.11a). However, it's not the dual radios that enable this mixed-mode performance, nor anything on the client side. Meru's control over the Media Access Control (MAC) layer of their APs gives them control over the density of clients and the quality of service, according to Anand.

"You can't just solve this by having two radios," he says, pointing to other companies like Proxim which offer products with dual radios.

Other companies looking into fixing the mixed-mode issue with WLANs include chipmaker Engim, which would use multiple channels for a single AP to increase traffic flow. However, Meru appears to be the first company to have announced a product addressing the issue directly.

Pricing for the new AP200 will be set around the time it ships in the fourth quarter.



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