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Presumably, no matter how many wireless clients you intend to support, you will eventually need to "hit the wire" in order to access other networks (such as the Internet). There are a number of different kinds of physical devices you can use to jump from wireless back to your wired infrastructure.
APs are widely considered ideal for "campus" coverage. They provide a point of entry to the wired infrastructure that can be configured by a central authority. They typically allow for one or two radios per AP, theoretically supporting hundreds of simultaneous wireless users at a time. They must be configured with an ESSID (Extended Service Set ID, also known as the Network Name or WLAN Service Area ID, depending on who you talk to); it's a simple string that identifies the wireless network. Many APs use a client program for configuration and a simple password to protect their network settings. All hardware access points provide BSS master services.