Meru Networks has launched a monster wireless access point, that operates on 12 channels at the same time, as the latest part of a voice-friendly "blanket" Wi-Fi architecture.
The company calls its new AP a "Radio Switch" to distinguish it from the little APs used by other vendors. Meru's technology blankets a building in Wi-Fi, with adjacent APs using the same channels, instead of trying to find different ones. The system, which Meru reckons is the fourth generation of Wi-Fi uses the intelligence in the switches and their controllers to sort out traffic flows from different clients.
"It's similar to the way cellular networks manage contention," said Ben Gibson, vice president of marketing at Meru. "The whole network is one virtual access point, which gives predictable transmission of data."
The switch can use the twelve non-overlapping 802.11a channels in the 5GHz band, and the three that 802.11b can manage in the 2.4GHz band. The RS-40000, RS-80000 and RS-12000 support four, eight and 12 out of these channels respectively. Each switch has one big omni-directional antenna for all the channels it supports.
"Deploying three-channel WLANs on a large scale is virtually impossible," said Gibson, contrasting Meru with switch vendors like Trapeze and Aruba. "To increase capacity, they have to make the cell size smaller, but then they lose mobility." Small cells imply lengthy hand-offs every few feet, he explained: "No amount of RF planning can answer the problems." Moving from one access point to the next always involves a delay in centralised switch architectures, he said.
With fewer cables to pull, and no site survey, Gibson reckons Meru's system saves 46 percent over rivals like Airespace/Cisco. Up to 150 of the switches, which Gibson describes as "beefy APs", can be managed by one controller.
"The controller is not in the data path," said Gibson. It handles management information , and discovers and co-ordinates the APs. Although a client will stay on the same channel, the hand-off between two APs has to be done with care: "As you move from one AP towards another, a copy of your connection is established at the new AP," said Gibson. "The controller tells the switches to handover at a set time, say T+200ms, and the old connection is torn down."
Gibson is not impressed with the switch from newcomer Extricom, which also uses a blanket architecture, with adjacent APs on the same channel. Both are pitching their products for voice use, and both have been tested in Japan. In Meru's system, the switches connect at Layer 3, which makes it more scalable, than Extricom's, claims Gibson. Extricom's ultra-thin APs have no MAC, and have to be connected directly to the switch: "We do not believe in a centralised switch with remote radios," said Gibson, pointing out that this was the technology proposed by AirFlow - which closed down.
Although Cisco's Airespace purchase has put the seal of approval on centralised switches with multi-channel APs, there is still time to establish "blanket" WLANs in the market, said Gibson. "The market is only five to ten percent penetrated. There is plenty of space for a new solution to take hold. Most of our clients have tried multi-channel deployments and when you get past twenty APs, you get problems."
Meru intends to establish a European presence, with announcements coming soon, said Gibson. But then, his colleague said that to us in Spring of last year, too.
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