I'm doing a study on how providers can increase usage of public hotspots, and found that they are using ORiNOCO® AP‐700,AP‐4000 ,Cisco 1200 and 1140 wifi access points. What is the maximum amount of users these devices can handle simultaneously? Thanks!
I don't know about specs on the ORiNOCO devices but the Cisco devices don't have "published" maximum association specifications that I've ever seen. You'll find various documents (like this Aironet FAQ, under the question about wireless handsets per AP) that give some vague numbers but I'm not aware of hard-and-fast published maximums. I suspect that any maximums you find published will relate to the APs ability to track associations and will be highly optimistic.
The amount of traffic that associated mobile units are moving and their data rate is going to determine the amount of free wireless bandwidth. I would guess that contention on the wireless media (the air) is going to be a problem long before the ability of those APs (which are all reasonably high-end) to handle the number of associations.
I use a rule-of-thumb with non-beamforming omnidirectional APs of no more than 20 clients per AP for a good user experience. APs with more antennas and / or radios (Xirrus, Ruckus, etc) will be able to handle significantly more. I'm talking about a scenario with Windows roaming user profiles, redirected "My Documents" folders, etc-- a wired network replacement in a corporate environment. For Internet access only you could probably double that number and see reasonable performance (provided your wired layer 2 and Internet uplink can handle it).
Planning for large numbers of wifi clients is still a bit of an art. Things have gotten better since Joel's question (hard to believe that was almost two years ago) and beamforming APs can make covering large numbers of clients a lot easier than "dumb" APs of just a couple of years ago.
There's a really good recently-published article at Tom's Hardware that speaks to the performance of APs with increasing numbers of clients: Why Your Wi-Fi Sucks And How It Can Be Helped
In that article they subject a variety of APs to a load of 60 clients and graph the results. You can get a feel, from the charts and the commentary, about what happens when the number of clients simultaneously associated with an AP does to performance.