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Đo lường, dụng cụ thử nghiệm, và các quá trình độc quyền chức năng. Thiết kế hệ thống bao gồm một số lượng đáng kể phần mềm sáng tạo, cùng với các xét nghiệm về chức năng cụ thể trên đường đi. h. Hội nhập thử nghiệm: | IEEE 802.11 WLAN Systems 1.3 Inside WLAN Devices This section briefly describes the guts of various WLAN devices. In order to test a device it is necessary to have at least some basic understanding of how the device works and what is inside it. The description is necessarily fairly superficial the reader is referred to datasheets and product descriptions for more information. In some cases even product literature will not help there is no substitute for taking a device apart to see what makes it tick. 1.3.1 Clients Clients are at the base of the WLAN pyramid and are the only elements that are actually in the hands of users. WLAN clients comprise basically any device that has a wireless interface and actually terminates i.e. sources or sinks data traffic. Examples of devices that can act as WLAN clients are laptops virtually every laptop shipped today contains a WLAN interface PDAs VoIP telephone handsets game consoles bar-code readers medical monitoring instruments point-of-sale POS terminals audiovisual entertainment devices etc. The number of applications into which WLANs are penetrating grows on a monthly basis the WLAN toaster is probably not too far in the future The WLAN portion of a client is required to perform the following functions 1. Association connection with a counterpart device such as an AP. Prior to association the client is not permitted to transfer any data. 2. Security and authentication functions to assure the counterpart device that the client is in fact who it says it is and is authorized to connect. 3. Protocol stack support principally of the TCP IP protocol so that applications can transfer data once the connection process is completed and everything is authorized. 4. Mobility functions such as scanning for higher-power APs and roaming from AP to AP when the client is in motion. The counterpart device to which a WLAN client connects is almost always an AP. The 802.11 protocol standard does allow a client to connect directly to another .
