My aironet 1100 series AP, which was configured with WPA-PSK, has worked without any problem for two years. Suddenly, without any change in configuration, it started dropping clients. Reconnecting clients get dropped again in a matter of seconds. The event log says the client "reached max retries".
It has never been upgraded since I bought it. I upgraded it to the last GD release of IOS, to no avail : the same problem persists.
The AP is set on the right .11d settings, and to select the least congested channel. I did try to select a fixed channel, which did not solve the problem. There is no other AP on the same channel ever receivable by netstumbler.
Since the problem appeared suddenly where there had been no configuration change, I am afraid there might be a hardware problem.