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INTEROP - Vendors spotlight 11n WLANs for the enterprise

Enterprise access points based on IEEE 802.11n will offer 100Mbps to 200Mbps throughput
  • John Cox (Network World)
  • 23 May, 2007 13:10

Three wireless LAN vendors are unveiling at Interop Las Vegas this week enterprise access points that will offer 100Mbps to 200Mbps throughput, shared among the Wi-Fi clients that connect to it.

All three, from Colubris, Ruckus, and Trapeze, are based on the IEEE 802.11n draft 2 standard.

Colubris plans to offer a two-radio access point, the Multiservice Access Point (MAP)-625. One radio is intended to support existing 802.11a, b, and g clients. The second radio, based on Atheros silicon, support the 11n draft 2 standard.

This approach lets enterprise users start adding 11n support into the WLAN infrastructure, which will still support existing wireless clients, until they, too, are outfitted with an 11n adapter, according to Carl Blume, Colubris' director of strategic marketing.

And, with existing clients on a dedicated radio, they won't throttle down the 11n connection. The 11n access point can detect, for example, an 11b client trying to connect with it, says Roger Sands, the company's vice president of engineering. When it does, the 11n chipset will "jump down" to the 11Mbps data rate which is the maximum for an 11b. A further performance hit follows if that 11b client is also an active talker, says Sands. "He's consuming more time on the access point, so more of the available [11n] bandwidth is being eaten up at the lower rate," he says.

The MAP-625 11n radio will deliver useable throughput of 100Mbps minimum, says Sands, with the 11abg radio adding about another 24Mbps. It has one Gigabit Ethernet port, which means the MAP-625 will need to connect to a Gigabit port on the nearest LAN edge switch.

For enterprise nets with Gigabit edge switches, the impact of 11n will be minimal. But closer to the network core, as a growing amount of 11n traffic is aggregated, then some LAN switches may have to be upgraded.

But, according to Sands, the new access point will work with existing Colubris WLAN controllers, without requiring any software or hardware changes to these centralized boxes. That's partly because the controllers were designed with enough capacity, processing power, and memory to handle 11n, and partly because the Colubris access points can switch WLAN packets on their own, without routing all data packets through the controller.

Colubris also supports a local mesh protocol that lets one of the two radios be used as a wireless backhaul where it's too costly or too difficult to pull Ethernet cable to a switch.

The MAP-625 will ship in Fall, 2007, with a list price of US$999, about 30 percent more than the existing dual-radio 11abg access point. "This kind of modest price differential gives customers the ability [with the MAP-625] to install an 11n-ready wireless net today, and no need to swap out access points in the future," says Blume.

Ruckus Wireless this week unveils the new 11n ZoneFlex WLAN product line, designed specifically to be easy to deploy and run for small and midsize businesses.

ZoneFlex consists of a new 11g access point, an existing 11g low-end access point for small offices, a new 11n draft 2 access point, and the ZoneDirector 1000, which is a controller available in 3 models to support up to 25 access points.

Both access points use Ruckus' patented built-in antenna technology: which uses a several discrete components that Ruckus software can combine in over 4,000 combinations to optimize the radio signal for a given location, signal environment and traffic load. This "beam-steering" antenna also boosts the range of Ruckus access points by 2 or 4 times compared to conventional omni-directional antennas, according to Selina Lo, president and CEO of the Sunnyvale, Calif. vendor.

Longer range has two benefits in enterprise networks. It can mean using fewer access points to cover a given area. But the more important benefit is that the signal between access point and clients is stronger and more consistent at any given distance, creating a more reliable wireless connection. Ruckus has used this antenna technology as the basis for its original product line of in-home wireless routers for streaming multimedia through an entire house.

The new ZoneFlex 2942 is the new11g access point, which looks deliberately like a non-descript gray clamshell, so as not to draw attention. It has two 10/100 Ethernet ports, allowing them to be daisy-chained to each other, without a separate cable run for each to a LAN switch. Ruckus promises 20Mbps of "sustained throughput" meaning that there's little or no variation, in large part due to the beam-steering antenna system.

Ruckus' existing five-port 2925 11g access point, designed for small office and hotspot-style deployments, can also be used with the ZoneFlex line.

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The ZoneFlex 7942 11n access point will be released in August or September. Initially, it will have one 2.4 GHz radio, that can support 11bg and 11n. Ruckus will eventually support a 5-GHz radio, for 11a and 11n. The Ruckus 11n radios will be able to switch between 11bg data traffic with clients, and 11n for a meshed wireless backhaul connection. A new mesh routing protocol will let the access points coordinate backhaul links to optimize throughput, according to Lo.

When any of these access points are powered up, they automatically search for ZoneDirector controller. Ruckus has created a set of Web-based wizard programs that let any computer user click on a few configurations to have the controller automatically apply the relevant WLAN and security settings to all attached access points. The process takes about five minutes, according to Lo.

Another new ZoneDirector program, called Dynamic PSK (for Pre-Shared Key), lets a first-time wireless user start the initial log-in via a Web screen. ZoneDirector downloads a unique encryption key with the wireless settings for that user's device. The key allows the user to connect securely to the wireless and remains in force until it's invalidated. An administrator can set a key expiration date for guests, for example, or delete keys through the controller if an employee leaves the company.

ZoneDirector has an internal authentication database but can also work with existing RADIUS or other authentication servers. It has a set of Web screens to show access point signal coverage and health, and a program to detect rouge access points.

The new ZoneFlex 2942 11g access point, and ZoneDirector will be available in June. The 2942 is priced at US$349. The controller comes in three models, for 6, 12, and 25 access points, at US$1,200, US$2,000 and US$3,500 respectively. The 7942 11n access point will be available in Q-3. The price has not been finalized.

Trapeze Networks is introducing its Mobility Ppoint(MP)-432 11n draft 2 access point. It, too, uses the Atheros dual-band MIMO chipset, in a 3x3 antenna configuration for each band. The two radios, one for 11bgn one for 11an, will be able to run at the same time. Two Gigabit Ethernet ports are the network uplinks.

"Our customers are not saying to us, 'we don't want to see your 11n products until the IEEE wraps a bow around the [11n] standard,'" says David Cohen, the company's director of product marketing.

When using the optional 40 MHz channels, which are double the typical WLAN channel, each radio will support a 300Mbps data rate, one in the 2.4-GHz band, and one in the 5-GHz band, or 600Mbps total for the access point. The TCP/IP throughput will be about 200Mbps per band, according to Cohen.

The new 432 models, modeled after a smoke detector, will work with the existing Trapeze controllers. As does Colubris, Trapeze can switch data traffic at the access points, instead of funneling all it back to the controller.

One unexpected issue facing enterprise users is that the 11n access points require more power to run than is supported by the existing Power-over-Ethernet 802.3AF standard, according to Cohen. To support most 11n access points, he says, users will have to upgrade their current 3AF infrastructure.

But Trapeze has designed the 432 so it can make use that infrastructure, though with some limitations. The internal electronics can take the existing power and use it to drive the full 300Mpbs data rate on one of the two radio bands. That may seem like half a loaf, but "that's better than just not working," says Cohen.

Another option possible with the 432 is to draw a second PoE 3AF line through one of the access point's two gigabit Ethernet ports. This second power connection would be enough to make the 432 run at full-bore 11n on both bands, according to Cohen. The 432 is designed to work unchanged with higher-powered PoE injectors, he says.

Trapeze will start beta testing of the MP-432 soon, with shipment due near year-end. Pricing is not final. The current 802.11abg access point is US$595. Cohen would only say the 11n product will be "less than US$1,500." "It's certainly a premium, but I think it's warranted when you're going from 54Mbps to 600Mbps," he says.