Also: Wi-Fi, WLAN, 802.11, access point, SSID, WPA3
A wireless LAN connects devices to a network over radio using the 802.11 family of standards, through access points that bridge the wireless medium onto the wired network and enforce the authentication and encryption that the shared airwaves demand.
Our take. Wi-Fi problems are radio problems and are diagnosed as network problems because the network is what people can see. Coverage, interference and the number of devices sharing a channel decide the user's experience far more than any setting on the access point, and the engineer who learns to read a spectrum survey fixes what three firmware upgrades did not.
An access point is a bridge between two media: on one side an Ethernet cable into the wired network, on the other a radio that devices in range can talk to. The radio is a shared medium, so every device on a channel takes turns, and the more devices and the more traffic, the more waiting. A network name, the SSID, identifies the wireless network; several access points can share one name so devices roam between them; and the channel each access point uses decides who it interferes with. The bands differ in character: the lower band reaches further and through walls and is crowded; the higher bands carry more and reach less. Most design questions are about which access point should be where, on which channel, at which power.
Generation
Marketing name
What it changed
Security to pair with it
802.11n
Wi-Fi 4
Multiple antennas; the first generation fast enough for most offices
WPA2 at minimum
802.11ac
Wi-Fi 5
Higher band only, wider channels, multi-user transmission
WPA2, WPA3 where supported
802.11ax
Wi-Fi 6 and 6E
Efficiency in crowded rooms; 6E opens a new band
WPA3 expected
802.11be
Wi-Fi 7
Wider channels and combining bands at once
WPA3 required
Open networks send everything in the clear; anyone in range reads it. Acceptable only with nothing to protect and encryption at every higher layer.
Pre-shared key networks, the home model: one passphrase for everyone, which means everyone can read everyone else's traffic and a leaver keeps the key until it is changed.
Enterprise authentication: each user or device authenticates individually through a central server, receives their own keys, and can be removed without changing anything for anyone else. This is what an office should run, and what the exams call by its standard's number.
WPA3: the current security generation, closing the offline password-guessing weakness of its predecessor and protecting even open networks with individual encryption where supported.
In practice
An office complains that Wi-Fi is slow in the afternoons, and the network team upgrades the access points, changes the firmware and doubles the internet connection. Nothing improves. A radio survey shows two access points on the same channel covering the same open-plan area, both at full power, so every device in the room can hear both and they interfere with each other constantly, and the afternoon is when the room is full. Lowering the power so each covers only its half, moving one to a clear channel and steering devices to the higher band fixes it in an hour. The complaint was about the network; the fault was in the air.
An access point does at radio what a switch does at the cable: it bridges devices into one segment. The difference is that the radio is shared and half-duplex, so devices take turns, and a switch's dedicated ports do not.
A VPN encrypts traffic from a device to a gateway wherever it is; wireless security encrypts the radio hop between the device and the access point. Public Wi-Fi with a VPN is protected on the hop and beyond; open Wi-Fi without one is protected by nothing.
Wireless security standards are one application of encryption, protecting the radio link. The link's encryption ends at the access point; anything sensitive still needs encryption end to end above it.
Key takeaways
→The radio is a shared, half-duplex medium; devices per channel and coverage overlap decide performance.
→Enterprise authentication gives each user their own keys; a shared passphrase gives everyone everyone's traffic.
→Diagnose the air before the network: survey, channel, power.
Certifications that test this
Vendor exams whose syllabus covers this concept — facts, cost and a preparation path on each page.
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FAQ
Why is the Wi-Fi slow when the internet connection is fast?
Because the bottleneck is the radio, not the line. Too many devices on one channel, access points interfering with each other, or a device far from the nearest access point all slow the shared medium regardless of how fast the wired side is.
Is a shared Wi-Fi password safe for an office?
No. Everyone who has it can decrypt everyone else's wireless traffic, and a leaver keeps it until it is changed for the whole office. Enterprise authentication, where each user logs in individually, is the office standard and what the certification exams expect you to specify.
Does hiding the network name improve security?
No. The name is still transmitted whenever a device connects, and hiding it makes devices announce which networks they are looking for. Use strong authentication and current encryption; the name is not a secret and was never meant to be.
Sources
The primary text this definition rests on. Read it before you trust ours.
IEEE 802.11, Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications (2020)
Wi-Fi Alliance, WPA3 Specification (2020)
IEEE 802.1X, Port-Based Network Access Control (2020)
