Spectrum analysis: 'Potato or potahto?' (Part 3)

Consider the many tradeoffs

In this third installment of our look into what role bundled spectrum analysis should play in Wi-Fi purchase decisions, let's chip away at a few other questions and considerations broached in Part 1 of this series.

Does SA run 24/7 or only when performance issues arise?

Spectrum experts from Aerohive, Aruba Networks, Juniper Networks and Motorola see the SA capability as something to turn to when inherent dynamic RF management tools in APs and/or WLAN controllers aren't sufficient.

BACKGROUND: Are all spectrum analyzers created equal? | The ins and outs of spectrum analysis, part 2

For example, when all three non-overlapping channels in the 2.4GHz range (channels 1, 6 and 11) are congested, "you need a spectrum analyzer," says Peter Lane, Aruba product manager.

Cisco's CleanAir SA, embedded into Cisco Aironet 3500 Series APs and its hardened outdoor 1550 APs, by contrast, runs 24/7 and is what Cisco calls "proactive," in that it will change channels automatically based on spectrum conditions.

"People assume that's an advancement," says Matt Gast, product manager at Aerohive. "It's another way of doing [WLAN RF management], but is it better? That's a whole other discussion."

Do SA capabilities carry greater weight in purchasing decisions than other characteristics of the WLAN system?

"All spectrum analyzers do is look at RF spectrum and tell you what's there," says Chip Greene, senior network specialist and wireless network engineer at the University of Richmond. His organization is in the process of replacing a Cisco thin AP/controller setup with Aruba gear.

"Every SA I work with does that; all are basically created equal, but the way they present the information to you isn't," he says, noting that remote diagnostics are very important in the university environment.

Greene acknowledges that the Cisco CleanAir spectrum database is "much deeper, but Aruba is deep enough for my needs" and offers a handy dashboard that displays devices with greater signal-to-noise ratio and other conditions.

He advises to "make sure there's a firm definition of what spectrum analysis is" when dealing with vendors. "[Cisco Radio Resource Management] and [Aruba Adaptive Radio Management] are analysis tools used by APs to mitigate noise. Spectrum is a tool used by engineers to maintain systems," he says.

Learn more about this topic

Cisco embeds spectrum analyzer in ASIC

Aerohive updates its 803.11n WLAN software

Spectrum analysis to be built into Aruba's Wi-Fi product line

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