"Wireless network technology tutorial" reading notes (a)
Wireless LAN definitions:
WLAN and a wireless computer network technology product of the combination, refers generally to wireless computer local area network transmission medium,
Utilizing radio and infrared wireless, or the like to provide a data communication peer connectivity.
One of the typical standard IEEE802.11 standard WLAN space, WiFi is the commercial name of the IEEE802.11.
Wireless LAN advantages:
(1) Mobility: network and host migration easy, unrestricted communication line environment, improved coverage, provides effective access functionality for portable devices.
(2) Flexibility: simple installation, flexible networking, the network may be extended to place the cable can not be connected.
(3) scalability: set or add the access point (the AccessPoint) or extension points (Extend Point)
(4) Economy: wiring can be used in difficult physical environments, saving cables, accessories and labor costs, can quickly form an interim low cost network.
Wireless LAN section limitations:
(1) Reliability: the traditional LAN channel error rate is less than 10 -9 , high reliability and stability. The WLAN radio channel is not very reliable, all kinds of interference and noise can cause fading and the error signal, which led to a decline in throughput performance and instability.
(2) compatibility with the coexistence:
Compatibility comprising: WLAN be compatible with the wired LAN, and a network operating system compatible with existing network software; various WLAN standards compatible with each other, the wireless device is compatible with different manufacturers.
Coexistence comprising: a band of the same or a different standard formats coexist, such as IEEE802.11 and Bluetooth coexistence system of 2.4GHz. Different frequency bands, coexistence system or standard, such as the 2.4GHz and 5GHz WLAN coexistence.
(3) the bandwidth and system capacity: lack of resources due to the frequency, WLAN channel bandwidth is much smaller than the bandwidth of the wired network, even if the multiplexing, the system capacity is also typically less than a wired network.
(4) Coverage: WLAN low power and high frequency limits of its coverage.
(5) Interference: outside interference may affect wireless channels and devices, internal WLAN will form self-interference, it can interfere with other wireless systems, planning and therefore need to be considered when using WLAN electromagnetic compatibility and interference immunity.
Move some theoretical knowledge, it really needs some theoretical knowledge or understanding of their own, ah, he said Mandarin is too meaningless.