Max number of users per AP ?

The limit for DHCP assigned IP's with Class C subnet mask is 253.

The rule of thumb is:

You can use an SNMP MIB browser to look at the number of MAC addresses you have in the table. Syslog output should also give you a clue as to what's happening. If the MAC addresses look weird, you might search Google for "MAC flooding".

Also, users getting "kicked off" (a very vague term) can be caused by running out of DHCP IP address leases as new MAC addresses appear. Check your DHCP server for sufficient IP addresses and make sure that the lease time is fairly short (i.e. 30 mins) if you're running a system with lots of transient users (hot spot, coffee shop, hotel, etc).

Drivel: 50 users per radio for 802.11a.

I don't have a number. I know of several low bandwidth WISP systems with more than 100 active users on a single radio. I've also done it with tests in the lab (using a different access point). The available bandwidth divides nicely between the 100 users. However, I've never tested the AP-2500 for capacity.

Proxim tech support does say in fact only 50 users for 802.11a, but 250 for

I will try shortening the DHCP lease time to 15 minutes, that may very well be the root of my problem.

-- Paul