WLAN vendors convene at Interop

Thin access points, mesh routers and new switches take center stage.

By John Cox
Network World, 04/25/05

Wireless LAN vendors will be out in force at the NetWorld+Interop show in Las Vegas next week with new or improved products.

Israeli WLAN start-up Extricom will use the show to launch thin access points and a central switch that boast patent-pending technology that detects and in effect sidesteps radio interference. As a result, executives say, access points can be packed much closer together than they can with conventional WLANs, boosting overall throughput and network reliability.

Extricom achieves this in part by using an approach similar to that adopted by ill-fated start-up AirFlow: by moving all media access control (MAC) functions from the access point to the central switch. The access point has no software, acting simply as a conduit passing wireless packets to the central switch.

The next step is to avoid radio interference. Extricom does this with an algorithm in programmable silicon in the central switch. The key change Extricom does in hardware is what rivals have tried to do in software, according to CEO Gideon Rottem. Via the algorithms, the switch can "see" the entire radio environment in real time - all the access points and wireless clients, and every packet moving between them. If a transmission from one access point is interrupted or degraded, the switch can have another Extricom access point handle communication with that client on a packet-by-packet basis.

"If Access Point 1 and Access Point 2 transmit at the same time, you'll have interference," Rottem says. "So the switch doesn't let them. By knowing at all times the complete radio map of the network, we can assess when and where to transmit, and through which access point."

Compared with conventional WLANs, Extricom lets more users be closer to a larger number of access points, and therefore lets them connect at the maximum possible throughput rates of 5M to 7M bit/sec for 802.11b and 20M to 25M bit/sec for 802.11g and 802.11a, Rottem says.

Sangikyo, a network engineering firm in Yokohama, Japan, has been beta testing the Extricom switch, initially for wireless VoIP covering the four floors of its headquarters. Sangikyo set up the switch and eight access points, testing up to 10 WLAN phones over 802.11b and 802.11a connections. "We've been able to support up to 10 simultaneous calls on one" access point, says Matthew Drechsler, a test engineer with Sangikyo's business development division.

In one test, Drechsler put two access points near each other, placed 10 calls on one of them, and then unplugged that access point's Ethernet cable. "All the clients roamed smoothly to the remaining access point with no delay or perceivable change in voice quality," he says. "It was quite impressive."

"You have guaranteed throughput for all clients, no co-channel interference, and voice that is smooth and latency free," he says.

To support high guaranteed data rates, Extricom users will have to add more access points in a given area, compared with other WLAN systems, Drechsler says. Currently the product supports only small networks. "We would like to see Extricom come out with a large-scale switch," he says.

The eight-port Extricom switch, with eight access points, will ship in May, priced between $8,000 and $14,000 depending on quantity and options, such as Power over Ethernet. The switch is intended to cover one floor of a building, or a branch office. The company is expected to ship a 32-port switch in the fall.

In other Interop wireless news:

Bluesocket plans to unveil its first line of WLAN access points, designed to work with its BlueSecure WLAN controllers. The controllers centralize security and management for third-party access points. By offering its own brand of access point, Bluesocket now can sell a complete range of WLAN products: access points, controllers and a recently introduced line of radio frequency sensors. The access points will support 802.11a/b/g WLAN clients. The first to ship will be the 1500 model, expected around July. Pricing has not been finalized.

Tropos Networks is scheduled to spotlight three WLAN mesh products. The key product is the 5210 Outdoor MetroMesh router, which is targeted at large, outdoor wireless mesh networks and now supports the 54M bit/sec 802.11g WLAN standard. The previous model was 802.11b, with a data rate of 11M bit/sec. In a wireless mesh, nodes communicate with each other to route packets to one or more gateways, which hand them off to a wired network or the Internet. The approach minimizes cabling costs and lets a WLAN be deployed more easily over a large area. Also new will be a companion indoor unit, the 3210 router, and a vehicle-mounted router, the 4210. The outdoor router costs $3,400, the indoor router is $1,850. The vehicle-mounted product is scheduled to ship later this year with price to be announced then.

3Com plans to show how its customers with older WLAN access points, such as the 8259 model, can replace the software in these devices so they can be managed and secured by the company's newer WLAN switches. The older access points were stand-alone devices that had to be managed separately. By giving them a new software load, these devices now become visible to the switch. 3Com's WLAN switch and thin access points are based on the Trapeze Networks products. The software is available for free on 3Com's Web site.

Recent Related Stories:

Aruba adds 802.11a/b/g outdoor access point

Xirrus offers high-capacity WLAN gear (Network World)

Wi-Fi QoS standard coming soon (Network World)

MIMO products boost 802.11g nets (Network World)

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