HP Manager Software manual Both enabled radios and disabled radios perform these scans

420CHAPTER 11: DETECTING AND COMBATTING ROGUE DEVICES

Ad Hoc Users Another type of rogue is a private WLAN user group. The group might be using an access point or software that provides access point functionality to a wireless laptop. Users can configure a wireless network interface card (NIC) in “ad hoc” mode and easily set up a simple peer-to-peer network. Although this WLAN might be isolated from the corporate WLAN, the users are stealing the air from legitimate WLAN users. The private WLAN can also cause RF interference with an authorized WLAN in other parts of the company.

RF Detection Scans All radios continually scan for other RF transmitters. Radios perform passive scans and active scans:

„Passive scans — The radio listens for beacons and probe responses.

„Active scans — The radio sends probe any requests (probe requests with a null SSID name) to solicit probe responses from other access points.

Radios perform both types of scans on all channels allowed for the country of operation (set by the country code when you created the network plan). 802.11b/g radios scan in the 2.4 GHz to 2.4835 GHz spectrum. 802.11a radios scan in the 5.15 GHz to 5.85 GHz spectrum.

Both enabled radios and disabled radios perform these scans.

Dynamic Frequency Selection (DFS)

Some regulatory domains require conformance to ETSI document EN 301 893. Section 4.6 of that document specifies requirements for Dynamic Frequency Selection (DFS). These requirements apply to radios operating in the 5 GHz band (802.11a radios).

In countries where Dynamic Frequency Selection (DFS) is required, MSS performs the appropriate check for radar. If radar is detected on a channel, the MAP radio stops performing active scans on that channel in accordance with DFS. However, the radio continues to passively scan for beacons from rogue devices.