User's Guide

• Desired Monitoring and Intrusion Protection Functionality
• Assets to be Protected
• Sensor Quantity and Placement
• Power and Data Cabling
Device Density
You should consider the density of 802.11a, b, g, and n devices:
• Support of a high number of users
• Support of high bandwidth consumption
• Localization of wireless network service.
The sensors should be separated by at least 10 feet from any installed APs to avoid radio defense. The
active transmissions of an AP can desensitize the sensor receiver radio on the same channel when
placed in close proximity of an AP.
Device Requirements per Area
While a single AirDefense sensor can monitor a very large area, distributing multiple sensors in such an
area can provide a much better idea of where a rogue device is physically located. By comparing the
RSSI values each sensor detects, you can find the device more easily. Three or more sensors are
required for the location tracking to work because triangulation is a requirement for the location
tracking to work.
Desired Monitoring and Intrusion Protection Functionality
Your decisions about sensor placement should also take into account what functionality you plan to use.
Five important functions that are dependent on sensor density or placement are:
• WEP Cloaking—For eective WEP Cloaking, several sensors should be deployed around the
perimeter of a building. Higher sensor density will typically yield better protection for your legacy
encryption devices.
• Location Tracking—To track a device, the device must be observed by three or more sensors on the
same floor plan. Higher sensor density will typically yield more accurate results.
• Connection Termination—To terminate a devices connection to your network, the device must be in
range of a sensor sending termination signals.
• Policy Enforcement—To ensure adherence to policies or to detect attacks against managed devices,
sensors must be able to receive a representative sampling of trac sent by all devices they are
monitoring.
• Rogue Detection—iEven sporadic emanations from wireless clients and s can reveal the presence of
rogues. You need to place sensors where transmissions from rogue devices can be detected as soon
as they enter the scanning area.
Assets to be Protected
• Wireless-capable devices that contain sensitive data must be protected.
• Wired networks protecting the wire from wireless breach. This approach is key to making wireless
monitoring deployment decisions in very large installations, such as military bases, airports, power
plants, campuses, etc.
Physical and Electromagnetic Interference
Legacy Content
1380 Extreme AirDefense User Guide for version 10.5.