Cognio's Spectrum Expert for WiFi 3.0

Spectrum analysis skills have never been common among network administrator specialties, but Cognio's latest release of Spectrum Expert for WiFi lets even analysis rookies combat WLAN interference. Several products exist in this category, at a wide range of prices, but Cognio's unique set of graphs and tools makes Spectrum Expert well worth its considerable premium.

Wireless LAN spectrum analysis provides a way to visualize and evaluate the RF airwaves essential to reliable WLAN communication. This type of expertise should not be confused with packet analysis, as spectrum analyzers interpret only information gathered about a WLAN's physical layer. MAC-layer analysis and packet capture fall within the scope of products like WildPacket's AiroPeek and AirMagnet's Laptop Analyzer.Unique Usability

Many vendors market spectrum analyzers that require expert skill levels. Standalone analyzers from companies like Anritsu, Agilent Technologies and Avcom of Virginia don't always detect WLAN interference and have a relatively steep learning curve. More recent offerings, such as Berkeley Varitronics Systems' BumbleBee, Cognio's Spectrum Expert for WiFi and MetaGeek's Wi-Spy, use the laptop PC or Pocket PC platforms with specialized hardware adapters. The newer products are more portable and less expensive than the standalone devices, with easier user interfaces. Although Spectrum Expert has some similarities to BumbleBee and Wi-Spy, Cognio's product represents a distinct evolution in WLAN spectrum analyzers. Spectrum Expert boils down its raw view of the spectrum into clear visuals and alerts.

The 2.4-GHz interference emanating from most microwave ovens perfectly showcases the differences between the Cognio and MetaGeek products. As the screen captures show (see page 18), both products paint a similar "Swept Spectograph" picture, but Cognio's view is far more accurate, a result of the product's finer-resolution bandwidth. In addition, Spectrum Expert for WiFi will automatically analyze the microwave's signal pattern, providing detailed metrics such as power, duty cycle and even what 802.11b/g channels the interference conflicts with--a feature noticeably absent from competing products.

Although Cognio is the sole developer of Spectrum Expert, the same application is available for the same price through Cognio's OEM partnerships, under the guise of AirMagnet's Spectrum Analyzer, WildPacket's OmniSpectrum and Fluke Network's AnalyzeAir. Cognio says future OEM versions will offer integration with each company's other WLAN analysis products. Only AirMagnet has begun that process, with its Survey and distributed Enterprise product lines. Although the integration of Cognio's spectrum analysis smarts into AirMagnet's Survey adds value by letting administrators gather coverage, performance and interference measurements in a single sweep. In addition, as integration costs drop, future collaboration between infrastructure manufacturers and Cognio could lead to WLANs that can detect, classify and even locate interference sources the way rogue access points are dealt with today.

Breaking It All Down

Spectrum Expert's interference classification and location features propel this product far ahead of the competition. From the moment the application is launched, Spectrum Expert automatically analyzes and pattern-matches the RF signals it detects against a growing database of known interferers. Once a signal is separated from the noise, the Device Finder feature can be used in Geiger-counter fashion to track down offending devices. Although unique to Cognio and its OEM partners, these features still induce some sticker shock. Priced at $3,995 for the hardware Cardbus adapter and Microsoft Windows analyzer software--and not including the required laptop--Spectrum Expert for WiFi costs more than 40 times MetaGeek's $99 Wi-Spy. Nevertheless, that's a bit like comparing a Porsche to a Hyundai, as Spectrum Expert is such a fine ride.

Besides Spectrum Expert's unique features, Cognio's third release has numerous enhancements aimed at distilling important RF information down another level. Two new charts, Channel Utilization and Interference Power, provide quick and precise representations of how much your wireless network and interference sources are competing with each other. Administrators also can define alarm conditions to be triggered if channel utilization exceeds a certain threshold, or if unwanted interference sources such as signal jammers are detected. None of Cognio's competitors provide this capability.

Better for Users

Improvements within the user interface are abundant as well. Charts have drag-and-drop functionality, and the new export-to-CSV feature makes it intuitive to analyze data within spreadsheet applications. As with previous releases, the upgrade path for existing customers is simply a free, downloadable update to the 3.0 release, available from Cognio's site.We put a beta release of Cognio's Spectrum Expert for WiFi 3.0 through its paces at our Syracuse University Real-World Labs® and found the enhancements to be welcome additions to a product we already respected highly. After installing Spectrum Expert on a Lenovo ThinkPad T43, we used the product to track down a variety of interfering devices, including a cordless phone, Bluetooth Piconet and a production access point. Our only gripe is the 'Device Finder' feature's one-second update speed, which makes for slow building walkabouts--move a couple feet, wait for signal update and repeat the process.

All in all, Cognio's Spectrum Expert for WiFi 3.0 release is another step in the right direction for making WLAN spectrum analysis and interference detection a much more intuitive process.

Jameson Blandford is the lab manager at the Center for Emerging Network Technologies at Syracuse University. Write to him at [email protected].