Most of today's terminal devices (laptops, mobile phones and similar devices) use wireless LAN networks for searching and services required by the user. Wireless LAN networks have become de facto the standard for connecting that type of device. They are attracting an increasing number of users due to their simple implementation, while providing a nominal transmission speed. Higher nominal transmission speeds facilitate access to information and reduce network costs. Wireless networks have many advantages, but the biggest disadvantage that creates many problems is security. The carrier of information in wireless networks are radio frequency waves and the medium through which they are transmitted is air. The information that is transmitted does not stay inside the object in the area covered by the wireless network and it is more often the target of attacks. In order to detect and prevent such types of attacks, various forms of security have been developed and are used. This paper describes the general characteristics of a wireless network through the example of a CISCO wireless LAN network. The types of architectures that can be applied in the creation of a wireless network, security protocols, as well as the basic principles of signal transmission and the equipment required to establish a network of this type are described.