7 Wireless Networking
Learn how Wi-Fi connects devices through access points, what affects wireless coverage and performance, and how to protect wireless networks.
foundations
connects devices using radio waves rather than a physical cable. is the most common wireless local area network () technology and is based on the family of standards.
specifies two parts of wireless communication: the physical layer, which sends and receives radio signals, and the medium access control (MAC) layer, which coordinates access to the wireless channel.
Clients, access points, and network names
In a typical network, a , such as a laptop or phone, communicates by radio with an . The AP connects wireless clients to a distribution system, usually the wired local network, and through it to other networks such as the internet. A home wireless router commonly combines an AP with routing, switching, and other functions in one device.
An AP advertises a network name called an . A finds and selects the network, then associates with the AP. If security is enabled, the must also authenticate. The AP then relays the ’s network traffic.
A site may use the same across several APs. This can allow a device to move between coverage areas; the device and network coordinate the transition, often called .
Radio coverage and shared airtime
uses radio-frequency bands, commonly 2.4 GHz and 5 GHz, and, on compatible equipment and where permitted, 6 GHz. Bands and channels offer different choices for coverage, capacity, and interference.
Radio signals weaken with distance and can be affected by walls, other networks, and electronic devices. Unlike a dedicated cable, the wireless channel is shared, so devices take turns transmitting. Congestion or interference can therefore reduce performance even when a remains connected.
An AP's radio coverage does not have a sharp boundary: signal strength gradually falls, and usable range depends on the environment, equipment, and interference. Adding APs can improve coverage, but their placement and radio-channel choices matter. Too many nearby networks sharing the same airtime can increase contention rather than improve service.
How carries traffic
In the common arrangement, clients send frames to an AP, which forwards traffic toward its destination. For example, when a phone requests a web page, it sends the request over to the AP. The AP passes it to the local network and router, and returning traffic follows the path back to the phone. The AP provides wireless access but does not necessarily perform the routing itself.
A is a group of stations communicating through an AP.
Choosing and maintaining security
Because a signal can extend beyond the walls of a home or office, wireless access must be protected as part of network security. The security configuration of both the AP and connected devices matters.
Common security choices include:
: Uses a shared passphrase for a home or small network and is the preferred option when all devices support it.
: Uses a shared passphrase and remains a compatibility option for devices that do not support WPA3. Use modern encryption settings, such as AES, rather than obsolete options.
: Organizations commonly use individual user or device credentials and an authentication server instead of one shared household-style password.
: Does not require a password and does not provide the same protection for the wireless link as an encrypted network.
Avoid obsolete protections such as and legacy WPA. A strong passphrase helps prevent unauthorized access, but it does not replace the router's separate administrator password. Change factory-default credentials and install vendor updates. When available, use a guest network for visitors or less-trusted devices; these measures reduce the chance that a compromised or unauthorized device can reach more sensitive systems.
Limits of visibility and device filtering
Hiding an does not encrypt traffic or reliably prevent discovery of a network. Filtering devices by their MAC addresses is also not a substitute for strong authentication. Security depends on the access controls and encryption in use, not on whether the network name is visible.
On public , do not treat the connection itself as trusted. Use encrypted services such as HTTPS and be cautious about sensitive activity.