Next, place an AP at each location you just plotted, and use a WLAN analyzer or the signal strength meter in your Cisco Aironet Client utility to measure and plot signal strength at incremental distances from each AP. Decide the minimum throughput that your users will require so that you can find where acceptable data rates are present.
Position your APs to avoid RF obstructions like metal columns and fire doors. If your survey turns up "dead spots," there may be hidden obstructions (I.E., water pipes inside walls). Decide where to place antennas - or your APs, if using integrated antennas - to optimize signal strength. For example, mounting an AP high on a wall in an open area is better than placing it on the floor in a room filled with chairs and tables. Also determine if other WLANs are operating in or near your venue to identify channels already in use.
You did not say whether you plan to use 802.11a or 802.11b on your Cisco 1200s, but since you need to support users with their own cards, you may want to stick to 802.11b. (If you use both, you'll need to perform a site survey for each, and relatively few users have single-mode 802.11a cards now.) Assign channels to adjacent APs that do not overlap - for example, 1, 6, 11 - avoiding overlapping footprints for APs on the same channel. You probably want all your APs to use the same SSID. If you enable WEP, APs with the same SSID should also use the same keys. This will allow stations to be configured just once to associate with any of your APs and roam without user intervention.
Most show networks do not use WEP - they are essentially public access WLANs, and anyone needing privacy must use a secure tunneling protocol. Enabling WEP means that only users with keys can use the show network. However, attendees will have to configure these keys and any user will be able to "sniff" other user traffic on the same WLAN. Also, any attendee with a 40-bit WEP card will not be able to access the network if you require 128-bit WEP. This may not be what you'd really intended, so think about what you want to accomplish first, then decide what security measures you need.
You'll find helpful info in your Cisco 1200 Hardware Install Guide. You may also want to read Cisco Packet Magazine's article on Preparing for Wireless LANs. For third party resources, here are two examples: TerraWave sells a Cisco WLAN Site Survey Kit, and GigaWave offers a Cisco WLAN Site Survey course. Finally, the CWNA Study Guide includes a good chapter on performing WLAN site surveys.
Dig Deeper on Wireless LAN (WLAN)
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