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May 2, 2005

Meru Says Twelve in One Box

By Glenn Fleishman

Meru Networks has announced its multi-radio omnidirectional Wi-Fi switch: It took me a while in a briefing last week to understand Meru’s approach, but I get it now. Meru puts four, eight, or 12 radios in a single switch which is deployed in zones around an office. Instead of using centralized network intelligence to manage the RF characteristics of their APs, they put many radios in a single box and don’t deal with trying to avoid co-channel interference at all. They can use combinations of 802.11a channels and three 802.11b nonoverlapping channels or go all 802.11a.

When you deploy Meru equipment, each switch runs multiple channels at once using omnidirectional antennas. Zones touch other zones and the switch decides which clients are allowed to join which channel based on load. All radios on the same channel use a virtual MAC address that prevents a client from deciding which radio to switch to. Instead, the switch decides which clients are on which channels.

The value of this is that clients don’t have to hop from channel to channel at zone interstices nor does the RF intelligence have to manage power in the same way that a network of APs operating on non-overlapping channels across coverage zones do.

A denser standard network involves adding more access points in given areas on non-overlapping channels to create more effective bandwidth. A denser Meru network involves creating more cells using their switches at the center.

Meru’s approach is part of a new trend which Extricom and Xirrus are part of in which the switch is out in the office instead of in the server room, and Layer 2 decisions are made at the switch itself, reducing bottlenecks. Authentication and other Layer 3 issues are tunneled back to server rooms.

Putting switches out in the office means that you have to have service-level agreements that can cope with the failure of a device that might be serving 100s of users and be the only coverage for a given area. The integrators that resell this equipment have to meet the enterprise need. For instance, Meru doesn’t have redundant, hot failover power supplies on their switches, which is common for server-room devices.

Posted by Glennf at May 2, 2005 12:54 PM

Categories: WLAN Switches

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