Site surveys are a critical part of any WLAN design.These surveys help the design
team identify placement locations for APs, determine how many APs are needed,
identify possible areas of RF interference, and determine the expected range of the
WLAN along with a slew of other important information.With the amount of
time and effort required to complete these surveys, they can be very costly and are
typically outsourced to an outside contractor that has a great deal of experience
and access to RF scanning equipment.This process is time consuming, mostly due
to the fact that a great deal of guesswork is involved in the initial planning followed
by modifications to improve performance post-implementation.
The Cisco wireless-aware LAN framework has some features that help make
this part of the design phase much easier.The wireless-aware framework allows
the network administrator to use tools included with the WLSE to perform their
own site surveys using in-house staff, thus cutting down on cost and time. Using these tools, administrators can follow a simple 5-step process to perform a complete
site survey in the WLAN environment.These five steps are:
1. A floor plan of the location to be surveyed is imported into the tool.
The tool supports a variety of electronic file formats including .bmp,
.jpg, and .gif. If an electronic file is unavailable, a rough building diagram
can be drawn within the tool.
2. Initial AP locations are added to the diagram to provide a rough estimate
of the number of APs required for the facility.
3. Cisco Aironet Series APs are installed in the facility at locations corresponding
to their diagram placements.
4. The installed Cisco Aironet Series APs are set to a site survey mode
known as “AP Scan Mode,” where they all assume the same channel and
transmit at maximum power. In this mode, the APs detect the presence
of one another and automatically select transmit power, frequency selection,
and other settings to fully cover the facility area.
5. Finally, the AP RF settings are fine-tuned in the “Client Walkabout”
mode. In this mode, an individual walks the facility areas where coverage
is needed, including the perimeter, with a client device that is sending
continual RF measurements back to the Cisco Aironet Series APs.
These steps are all that are required to perform a site survey using the Cisco
wireless-aware LAN framework. All future WLAN management and monitoring
can be done through the WLSE based on current information from the constant
WLAN RF monitoring data stream. Additional APs can be added or existing APs
can be moved based on this information.