Windows 7 / Networking

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Deploying Wireless APs

To deploy your wireless APs, do the following:

1. Perform an analysis of wireless AP locations based on plans of floors and buildings.
2. Temporarily install your wireless APs.
3. Perform a site survey analyzing signal strength in all areas.
4. Relocate wireless APs or sources of RF attenuation or interference.
5. Verify the coverage volume.
6. Update the architectural drawings to reflect the final number and placement of the wireless APs.
7. Configure TCP/IP, security, and RADIUS settings.

These steps are discussed in more detail in the following sections.

Note: An alternate method of performing a site survey is to move a single wireless AP around to various locations within your site to discover interference issues and identify the eventual locations of your wireless APs. This method allows you to determine the feasibility of a wireless network within your site before you install numerous wireless APs.

Perform an Analysis of Wireless AP Locations

Obtain or create scaled architectural drawings of each floor for each building for which wireless access is being planned. On the drawing for each floor, identify the offices, conferences rooms, lobbies, or other areas where you want to provide wireless coverage. It might be useful to enable wireless coverage for a building in its entirety rather than for specific locations within the building. This type of coverage can prevent connectivity problems that might result from undocking a laptop from an office for use in a different part of your building.

On the plans, indicate the devices that interfere with the wireless signals, and mark the building construction materials or objects that might attenuate, reflect, or shield wireless signals. Then indicate the locations of wireless APs so that each wireless AP is no farther than 200 feet from an adjacent wireless AP.

After you have determined the initial locations of the wireless APs, you must determine their channels and then assign those channel numbers to each wireless AP.

To select the channels for the wireless APs

1. Identify the wireless networks owned by other organizations in the same building. Find out the placement of their wireless APs and the assigned channel.
   Wireless network signal waves travel through floors and ceilings, so wireless APs located near each other on different floors need to be set to non-overlapping channels. If another organization located on a floor adjacent to your organization's offices has a wireless network, the wireless APs for that organization might interfere with the wireless APs in your network. Contact the other organization to determine the placement and channel numbers of their wireless APs to ensure that your own wireless APs that provide overlapping coverage use a different channel number.
2. Identify overlapping wireless signals on adjacent floors within your own organization.
3. After identifying overlapping coverage volumes outside and within your organization, assign channel numbers to your wireless APs.

To assign the channel numbers to the wireless APs

1. Assign channel 1 to the first wireless AP.
2. Assign channels 6 and 11 to the wireless APs that overlap coverage volumes with the first wireless AP ensuring that those wireless APs do not also interfere with other coverage volumes with the same channel.
3. Continue assigning channel numbers to the wireless APs ensuring that any two wireless APs with overlapping coverage are assigned different channel numbers, and separated by at least five channels.

Temporarily Install Your Wireless APs

Based on the locations and channel configurations indicated in your plan-based analysis of wireless AP locations, temporarily install your wireless APs.

Relocate Wireless APs or Sources of RF Attenuation or Interference

In locations where signal strength is low, you can make any of the following adjustments to improve the signal:

1. Reposition the temporarily installed wireless APs to increase the signal strength for that coverage volume.
2. Reposition or eliminate devices that interfere with signal strength (such as Bluetooth devices or microwave ovens).
3. Reposition or eliminate metal obstructions that interfere with signal propagation (such as filing cabinets and appliances).
4. Add more wireless APs to compensate for the weak signal strength.
5. Purchase antennas to meet the requirements of your building infrastructure.

Note: If you add a wireless AP, you might have to change the channel numbers of adjacent wireless APs.

For example, to eliminate interference between wireless APs located on adjoining floors in your building, you can purchase directional antennas that flatten the signal (forming a donut-shaped coverage volume) to increase the horizontal range and further decrease the vertical range.

Verify Coverage Volume

Perform another site survey to verify that the changes made to the configuration or placement of the wireless APs eliminated the locations with low signal strength.

Update Your Plans

Update the architectural drawings to reflect the final number and placement of the wireless APs. Indicate the boundaries of the coverage volume and where the data rate changes for each wireless AP.

Configure TCP/IP, Security, and RADIUS Settings

Configure your wireless APs with the following:

• A new wireless network name and strong administrator password
• A static IPv4 address, subnet mask, and default gateway for the wireless subnet on which it is placed
• WPA2 or WPA with 802.1X authentication (WPA2-Enterprise or WPA-Enterprise).

Configure the following RADIUS settings:

• The IP address or name of a primary RADIUS server, the RADIUS shared secret, UDP ports for authentication and accounting, and failure detection settings
• The IP address or name of a secondary RADIUS server, the RADIUS shared secret, UDP ports for authentication and accounting, and failure detection settings
• To balance the load of RADIUS traffic between the two NPS servers, configure half of the wireless APs with the primary NPS server as the primary RADIUS server and the secondary NPS server as the secondary RADIUS server. Then, configure the other half of the wireless APs with the secondary NPS server as the primary RADIUS server and the primary NPS server as the secondary RADIUS server.
  If the wireless APs require vendor-specific attributes (VSAs) or additional RADIUS attributes, you must add the VSAs or attributes to the wireless network policy of the NPS servers. If you add VSAs or RADIUS attributes to the wireless network policy on the primary NPS server, copy the primary NPS server configuration to the secondary NPS server.