1) Ad-Hoc Network
 

All computers -desktops and/or portables-  may connect directly with their partners (peer-to-peer connection).

One of the wireless computers manages all transfers among the rest of the equipments, so every computer in the wireless network -desktop and/or portable- must connect to the manager in order to establish communication with its partner. As a security measure, this PC acting as a manager also controls the access to the network by the wireless stations. 

To set up an Infrastructure environment, the IEEE 802.11 standard defines the presence of an Access Point, which must be installed on the PC wanted to act as network manager.