User's Guide

9. Move the target device to the anticipated fringe where a neighboring sensor would become primary.
10. At the fringe of coverage, signal strength should be no less than -70 dBm to assure termination
ability.
11. Move AirDefense Mobile to the anticipated location of the next sensor and use the same procedure
to ensure that its anticipated coverage area is valid.
If the above sensor placement proves adequate from a coverage and cost of placement perspective,
factors observed during this analysis may be extrapolated to other locations of similar construction.
Sensor Placement with WEP Cloaking
WEP Cloaking will typically require a higher density of sensor deployment than most other applications.
This puts WEP cloaking in the highest category sensor density deployments similar to Location
Tracking.
Considerations for Sensor Placement with WEP Cloaking
For eective WEP Cloaking, there are two important considerations:
• Spatial coverage - The sensors enabled with WEP Cloaking must at a minimum cover the same area
as the s and wireless clients they are protecting.
For this requirement, you should leverage any site surveys you conduct or have conducted for
placement of s as aids to sensor placement decisions. Another option is using a WLAN simulation
tools such as LAN Planner.
For example, in a typical retail location most wireless point-of-sale devices will be in the front of the
store near the check-out stations. Assuming the hacker would be outside of the building, sitting in
the front parking lot, it would make sense to place at least 2 sensors in each of the corners in the
front of the store. If there is public access from the back of the building or the retail location is
surrounded by parking areas, you may want to consider additional sensors in the back for complete
protection.
• Channel coverage - A single sensor should not be required to cloak more than 3 s at a time.
For eective cloaking there must be sucient cha WEP frames to confuse the statistical WEP
cracking tools. At the same time, the sensors must perform regular Wireless IPS scanning on other
channels. The sensors are designed to intelligently adjust their frequency scanning patterns.
However, to maximize cloaking eectiveness and scan all other channels for possible intrusions,
sensors should not be expected to cloak more than three APs, or more specifically three unique
communication channels at a time.
For Adequate Protection
Typically it will take several sensors deployed at the perimeter of the building to adequately protect all
wireless devices with WEP Cloaking. This also implies that, even in small stores, it may take more than
one sensor for adequate WEP Cloaking protection; the higher the density of sensors you deploy, the
better your legacy encryption devices will be protected. Any deployment should start with a site survey
or RF simulation of the WLAN environment, followed by a mapping of sensor coverage to access point
coverage of unique channels.
Sensor Placement with Location Tracking
Sensor density and sensor placement are the most important factors regarding overall positioning
resolution. Due to the nature of high frequency signals (2.4 GHz and 5 GHz) and limited signal strength
Legacy Content
Planning Your Sensor Placement
Extreme AirDefense User Guide for version 10.5. 1383