WLANs are often implemented in homes, offices, and campus environments. Only the 2.4 GHz, 5.0 GHz, and 60 GHz frequencies are used for 802.11 WLANs. The ITU-R regulates the allocation of the RF spectrum, while IEEE provides the 802.11 standards to define how these frequencies are used for the physical and MAC sublayer of wireless networks. The Wi-Fi Alliance certifies that vendor products conform to industry standards and norms.

A wireless client uses a wireless NIC to connect to an infrastructure device, such as a wireless router or wireless AP. Wireless clients connect using an SSID. APs can be implemented as standalone devices, in small clusters, or in a larger controller-base network.

A Cisco Aironet AP can use an omnidirectional antenna, a directional antenna, or a Yagi antenna to direct signals. IEEE 802.11n/ac/ad use MIMO technology to improve throughput and support up to four antennas simultaneously.

In ad hoc mode or IBSS, two wireless devices connect to each other in a P2P manner.

In infrastructure mode, APs connect to network infrastructure using the wired DS. Each AP defines a BSS and is uniquely identified by its BSSID. Multiple BSSs can be joined into an ESS. Using a particular SSID in an ESS provides seamless roaming capabilities among the BSSs in the ESS. Additional SSIDs can be used to segregate the level of network access defined by which SSID is in use.

A wireless client first authenticates with an AP, and then associates with that AP. The 802.11i/WPA2 authentication standard should be used. AES is the encryption method that should be used with WPA2.

When planning a wireless network, non-overlapping channels should be used when deploying multiple APs to cover a particular area. There should be a 10-15 percent overlap between BSAs in an ESS. Cisco APs support PoE to simplify installation.

Wireless networks are specifically susceptible to threats, such as wireless intruders, rogue APs, data interception, and DoS attacks. Cisco has developed a range of solutions to mitigate against these types of threats.