Wireless networks operate using radio waves to connect devices within a building or campus without cables. There are three main types of wireless network connections: point-to-point links between two devices, point-to-multipoint connecting multiple devices to a central access point, and multipoint-to-multipoint allowing any device to connect to any other. While wireless networks provide mobility and convenience, security measures must be implemented like changing default passwords, filtering devices, and enabling firewalls to prevent unauthorized access to the network.