WIFI Network

Wi-Fi network diagram contains at least one access point and at least one client. It is also possible to connect two clients in point-to-point (Ad-hoc) mode when the access point is not used, and the clients are connected via network adapters “directly”. The access point transmits its network identifier ( SSID ) using special signal packets at a speed of 0.1 Mbps every 100 ms. Therefore, 0.1 Mbps is the lowest data rate for Wi-Fi. Knowing the SSID of the network, the client can find out if it is possible to connect to this access point. When two access points with identical SSID fall into the coverage area, the receiver can choose between them based on signal strength data. The Wi-Fi standard gives the client complete freedom in choosing the criteria for the connection . The principle of operation is described in more detail in the official text of the standard ^[11] .

However, the standard does not describe all aspects of building wireless local Wi-Fi networks. Therefore, each equipment manufacturer solves this problem in his own way, applying those approaches that he considers the best from one point or another. Therefore, there is a need to classify methods for constructing wireless local area networks.

By the method of combining access points into a single system, we can distinguish:

• Autonomous access points (also called standalone, decentralized, smart)
• Access points operating under the control of the controller (also called "lightweight", centralized)
• Uncontrolled, but not standalone (managed without a controller)

By the method of organization and management of radio channels, you can select wireless local area networks:

• With static radio channel settings
• With dynamic (adaptive) radio channel settings
• With a "layered" or multi-layer structure of radio channels.
• Allows you to deploy the network without laying the cable , which can reduce the cost of deployment and / or expansion of the network. Places where it is impossible to lay the cable, for example, outdoors and in buildings of historical value, can be served by wireless networks.
• Allows access to a network of mobile devices.
• Wi-Fi devices are widely marketed. Equipment compatibility is guaranteed through mandatory certification of equipment with the Wi-Fi logo.
• Mobility. You are no longer tied to one place and can use the Internet in a comfortable environment for you.
• Within the Wi-Fi zone, several users can access the Internet from computers, laptops, phones, etc.
• Radiation from Wi-Fi devices at the time of data transfer is an order of magnitude .
• However, Wi-Fi is suitable for using VoIP in corporate networks or in a SOHO environment. The first equipment samples appeared in the early 2000s, however, they entered the market only in 2005 . Then companies such as Zyxel , UT Starcomm , Samsung , Hitachi and many others introduced Wi-Fi phones to the VoIP market at “reasonable” prices. In 2005, ADSL ISP providers began providing VoIP services to their customers (for example, the Dutch ISP XS4All ^[en] ). When VoIP calls became very cheap, and often even free, providers who were able to provide VoIP services were given the opportunity to open a new market - VoIP services. GSM phones with integrated Wi-Fi and VoIP capabilities have begun to enter the market , and they can potentially replace wired phones .