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Roll Your Own Interference Signatures With AirMagnet

Even the best wireless networks can take a beating when RF interference is present. As anyone who has an understanding of Wi-Fi will tell you, interference is the one threat to the WLAN that you can't really do much to prevent from a configuration standpoint. When interference does show up, accurate classification and remediation can be the key to client success or frustration. Fluke Networks has just freshened up its AirMagnet Spectrum XT analysis tool as a leading weapon in the war on interference.

Wireless network admins have a larger problem set to deal with than their wired networking counterparts. Both are on the hook to solve issues for their connected client devices, but the wired-only folk have the luxury of having all of their bits tidily wrapped in the jacket of the UTP that makes up network wiring. The chances of external signals or electrical noise impacting properly installed Category 6 wire are fairly insignificant. But when your data is in the air, and especially when high data rates are in use, the possibility of interference directly impacting network performance is real and easily demonstrated.

An increasing number of wireless access point models have built-in interference detection capabilities, but they typically can't tell you the whole interference story. Their limitations include their fixed locations and limited interference signature detection abilities. Though getting limited interference detection from your access points is beneficial, most environments still benefit from an easily deployed tactical tool that has the benefit of frequent signature updates--like AirMagnet Spectrum XT 3.0.1.

Existing customers of Spectrum XT will appreciate the new capabilities of 3.0.1, while tire-kickers might find the latest feature set to be a differentiator over the likes of Cisco’s Spectrum Expert Wi-Fi tool (which I currently use). Most notable is what Fluke Networks calls Zero Day Detection for unknown interferers. While the name might be a little dramatic for what is actually being classified, the fact that new energy patterns can form the basis of custom RF signatures is compelling. Even if you can’t tell what the interference source is, there is certainly value in recognizing repeat unclassified offenders along with those that the tool can identify (like Bluetooth devices and Zigbee clients). In this regard, you may know that a signal is problematic, without necessarily knowing what is making the noise. Spectrum XT lets you define a signature on the fly, so if it comes up again you can realize that multiple devices of the same type are in play in your environment. This can be pivotal in eventually figuring out what you’re up against.

Also progressive for this type of tool, Spectrum XT 3.0.1 can make sense of Meru’s virtual cell architecture. It is not uncommon for wireless tools to only show a single MAC address for an entire Meru environment regardless of how many APs are in use (the virtual MAC), but Spectrum XT 3.0.1 will now show all Meru AP physical addresses.

There are a number of other enhancements to the latest version relating to reporting, improved multipane views, and support for specific Intel 802.11n adapters that may or may not be of interest, depending on the needs of each given environment. I like that Spectrum XT 3.0.1 is USB-based and doesn’t require a PCMCIA slot, which means a lightweight netbook can be used instead of a full-sized laptop. Though I use other AirMagnet products, Spectrum XT 3.0.1 is not yet in my toolbox. But it is on my Christmas wish list.

Other than being a customer, Lee Badman has no relationship with AirMagnet.