Wireless Access Points

When we first started the iLearn project, we didn't allow the ipods to connect to the wireless network in the schools.  Instead single access points was installed in the classrooms where the ipods was to be used.  We did this for a couple of reasons, 1) we had not perfected the wireless security for the ipods 2) we didn't realize how the ipods would be used, and 3) the terms of the iLearn grant stipulate that their be unlimited access to the students.  The third item is what cause the most problem, the networks in the schools are protected by a content filter, and to allow access to the ipods would require that access be given to all users attached to the network. When you used a single access point you have to do a little bit of research, to keep from conflicting with other APs in the area. Here is a couple of rules for installing APs  for use:
1) Check the signal strength and channel of adjacent APs, if you are going install a new AP you need to make sure you are ample distance away from the other APs. If you are to close to the other APs and also happen to talk on the same channel, the signal will be diminished or there could be areas where there is not signal.
Let me elaborate on this a little: Wireless signal operates in a radio frequency, the WiFi signal is a relatively weak signal. Its signal strength follows the same laws as all wireless devices.  1) the farther away from the source the weaker you signal will become. 2) objects that interfere  with the signal, also decrease the signal strength. Walls, doors, Low-E glass will limit radio waves 3) radio waves propagate out in a circle fashion, they don't bend around corners.

 The channel of the AP.  Since an AP uses radio frequency to broadcast data, different AP have to be on different channels to keep from butting heads. The picture to the left shows the loss in signal if a channel conflict is created. Notice the breaks in the rings, for good signal the rings would be complete and not broken, much like the rings in a tree.

 Here is a example of what it looks like when two APs are to close together and talking on the same channel.

2) Different SSIDs  The SSID is the name of the AP that gets broadcast. If the AP is going to be a continuation of a existing wireless network which would allow roaming, then it is best to keep the same SSID name. This way no matter where you are at in the school the same wireless network would be available.  But on the otherhand, if you are just going to have a hotspot, which is a dedicated wireless area that usually has one use, in this case connecting ipod to the internet.

After we figured out the wireless security of the ipod and realized that all the teachers will be using the devices in the school; we allowed the ipods to attach to the wireless network in the school which also allowed roaming.