What is the knowledge of wireless lan?

Wireless LAN is a commonly used network structure. Generally, small wireless networks in the home are easy to manage, so the Enterprise-type wireless LAN structure is much more complicated. Next, let's introduce the basic concepts of Wireless LAN.

Wireless Local Area Networks (WLAN) is a very convenient data transmission system. It uses the Radio Frequency (RF) technology to replace the outdated Coaxial copper wire) the local area network makes it possible for users to use a simple access architecture to achieve Portable Information and convenient access to the world ｡

Why Wireless Local Area Network

For one of the main tasks of local network management, it is easy to get bored when laying cables or checking whether cables are broken, and it is not easy to find the broken lines in a short time, due to the constant updates and development of enterprises and application environments, the original enterprise network must be re-deployed and network lines must be re-installed. Although the cables are not expensive, however, the cost of wiring is high for technicians, especially for old buildings. Therefore, setting up a wireless LAN becomes the best solution ｡

What is the need for a wireless local area network?

A wireless local area network is not used to replace a wired local area network, but to make up for the shortcomings of a wired Local Area Network to extend the network. The following situations may require a Wireless Local Area Network

◆ Users without a fixed workplace

◆ Wired Local Area Network erection is subject to environmental restrictions

◆ Used as a standby system for wired Local Area Network

Wireless LAN Access Technology

Currently, when designing wireless local area network products, manufacturers have a variety of access design methods, which can be roughly divided into three categories: narrow-frequency Microwave (Narrowband Microwave) technology and Spread Spectrum) technology, and Infrared (Infrared) technology. Each technology has its own advantages and disadvantages, limitations, and comparison. Next we will discuss these technical methods in detail ｡

Technical Requirements

Because the wireless LAN needs to support high-speed and burst data services, it also needs to solve problems such as multi-path fading and crosstalk between subnets during indoor use. Specifically, the wireless LAN must meet the following technical requirements:

(1) Reliability: The system packet loss rate of the wireless LAN should be less than 10-5, and the error rate should be less than 10-8 ｡

(2) compatibility: for indoor wireless LAN, try to make it compatible with the existing wired LAN in the network operating system and network software ｡

(3) data rate: to meet the business needs of the LAN, the data transmission rate of the wireless LAN should be at least 1 Mbps ｡

(4) communication confidentiality: as data is transmitted in the air through wireless media, the wireless LAN must take effective measures at different levels to improve communication confidentiality and data security performance ｡

(5) Mobility: supports full or semi-mobile networks ｡

(6) energy-saving management: when there is no data sending and receiving, the site machine is in sleep state, and then activated when there is data sending and receiving, thus saving power consumption ｡

(7) miniaturization and low price: This is the key to the popularization of Wireless LAN ｡

(8) electromagnetic environment: the impact of electromagnetic on human body and surrounding environment should be considered in a wireless LAN ｡

Hardware

(1) wireless network card. The function of the wireless network card is basically the same as that of the network card in the Ethernet. It acts as an interface of the wireless LAN, and can realize the connection and communication between clients in the wireless LAN ｡

(2) Wireless AP. AP is short for Access Point. Wireless AP is the Access Point and wireless gateway of the wireless LAN. Its function is similar to a hub in a wired network ｡

(3) wireless antennas. When the network devices in the wireless network are far away from each other, as the signal decreases, the transmission rate will obviously decrease, so that the normal communication of the wireless network cannot be realized, at this time, we need to use a wireless antenna to enhance the received or sent signals ｡