Aruba Rolls Out New "Grid" Architecture

Aruba Wireless Networks has a new twist on the enterprise wireless LAN industry's design struggle between coverage and capacity.

Dave Molta

September 2, 2004

3 Min Read
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Unfortunately, dense deployments can be both expensive and difficult todesign. Because traditional products generally have required theinstallation of new UTP cabling for each AP, every new AP carries withit capital as well as operating costs. Depending on the type of facilityand prevailing labor rates, installation alone can cost hundreds or eventhousands of dollars per AP.

Aruba Wireless Networks has a different idea, something it calls theWireless Grid. The concept of wireless grids that use mesh architectureshas been the subject of academic research for several years, but Aruba's twist on the term is different.Rather than a mesh design, Aruba's solution can best be thought of as anultra-dense micro-cell deployment. Instead of going through the time andeffort of conducting a detailed site survey, pulling UTP wiring forevery new AP and installing above the ceiling, you simply pluginexpensive mini-APs into existing spare Ethernet jacks. Aruba claimsthat most organizations have plenty of spare ports. Presumably, aminimum number APs is required to provide full coverage within abuilding. But as you add more APs beyond this minimum, the systemautomatically reconfigures the RF environment, creating smaller andsmaller coverage cells and, therefore, more capacity per user. Aruba hasgone so far as to announce a partnership with Ortronics, a longtimeleader in structured wiring systems, to embed an AP into a modified walljack.

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For many in the industry, this vision has incredible appeal for severalreasons. In theory, at least, installation of a WLAN becomes as simpleas plugging a bunch of little APs into Ethernet jacks. Need morecapacity? Simply plug in more APs. No more fussing with complicatedphysical site surveys or logical RF models; just plug and play. Second,by increasing the density of APs, you increase capacity. When youconsider that there are now 24 non-overlapping radio channels in the5-GHz band, such dense deployments offering very high throughput peruser finally are becoming feasible. Lastly, as you increase the densityof APs, you also enhance your ability to use the WLAN for location-basedapplications.

As you might suspect, there are some challenges. All those extra APsincrease both the cost and the need for faster switches. In response,Aruba has introduced a new switch that promises 3.6 Gbps ofAES-encrypted throughput. The APs themselves are reasonably priced ($375to $395 list price, depending on model), but they are single-radio abgAPs. That means they can support either 11b/g or 11a, but not both atthe same time. Aruba's new pricing model allows organizations toeffectively lease APs and software for a fixed annual fee--a strategythe company feels will be appealing to organizations with constrainedcapital budgets but flexible operating budgets.Beyond cost, there's the question of how well the system will actuallywork in real-world environments. For example, even if Aruba really candynamically tune its APs for coverage and capacity, there's no easy waytoday to control the output power of client radios. That can lead tosignificant interference. Aruba executives assert that this is a validissue, but that the asymmetrical nature of WLAN traffic makes it amanageable problem. And while today's offering consists of APs thattypically are mounted at eye-level, the next generation of APsintegrated with wall jacks will lead to some interesting radiopropagation issues since locating APs at floor level isn't considered abest design practice.

Those reservations aside, give Aruba credit for continuing to innovatein the enterprise WLAN market. We're anxious to get our hands on the newsystem as part of a planned autumn review of WLAN switching systems.

For more information, visit Aruba Networks.

-- Dave Molta, [email protected]

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