Starting now, you no longer have to buy a software application to monitor your enterprise wireless LAN. You can just rent one online.

AirTight Networks this week unveiled a software-as-a-service version of its SpectraGuard Enterprise WLAN intrusion monitoring and prevention application, called SpectraGuard Online. Users still have to plug in preconfigured AirTight radio frequency sensors at their site. But the data these sensors collect is sent to servers at a hosting facility, where it's processed for the customer's network administrators.

The goal is to make WLAN intrusion prevention more affordable and easier to deploy for companies of all sizes, according to executives for the company. The basic SpectraGuard software is unchanged, but there are some coding changes to minimize delay in the wide-area connection between the hosted data center and the customer site.

AirTight is one of several vendors offering enterprise software that constantly monitors the Wi-Fi spectrum, usually with a network of RF sensors, for radios trying to connect to the WLAN or to users on it. Some vendors are small specialty vendors such as AirTight and AirDefense. Other WLAN vendors, such as Aruba, often include some intrusion detection/prevention features, either their own or under license from an OEM.

While managed services for WLANs have been around for several years, separate security services are rarer. VeriSign partnered with AirMagnet in 2007 to launch a managed wireless security service for intrusion prevention.

Based on data from the sensors, AirTight's SpectraGuard technology can detect radio activity, classify different threats and rate their severity, apply a range of enterprise usage and security policies, and block wireless connections. The sensors also can locate radio devices, and display in floor plans a coverage map of access points, and of the AirTight sensors, so users can see any gaps between the two.

AirTight has unbundled SpectraGuard's capabilities and made them available in two different services: one for monitoring and detection, one for countering and blocking detected threats. The unbundling lowers the cost and complexity for users to deploy WLAN protection, and lets them choose only the capabilities they need, according to AirTight executives.