Access Point
A bridge between wireless stations and a wired LAN, with association and encryption.
Level: beginner
What is it?
A wireless access point (AP) connects Wi-Fi stations to a wired LAN. It manages radio beacons, association, authentication/security negotiation, and the bridging of wireless traffic into the LAN.
Why does it matter?
An AP extends local connectivity to wireless devices, but wireless access introduces airtime contention, radio interference, mobility, and authentication concerns beyond ordinary wired Ethernet.
Mental model
The AP is a wireless bridge and radio coordinator. A station must associate and complete the configured security exchange before it can send normal network traffic.
How it works
- Association establishes a station relationship with a WLAN; authentication and encryption configuration control access.
- Wi-Fi is a shared radio medium, so airtime, channel width, interference, and signal-to-noise ratio affect throughput.
- Multiple APs can support roaming, but roaming behavior depends on client and network configuration.
- An AP may bridge to a VLAN or apply policy; it is not inherently the IP router or DHCP server.
- WPA2/WPA3 configuration, credential handling, and firmware updates matter for security.
Steps
- The station scans for the target SSID and discovers the AP.
- It associates and completes the configured security/authentication exchange.
- The station obtains IP configuration, often through DHCP, and sends frames through the AP.
- The AP bridges traffic to the wired LAN or applies configured VLAN/policy behavior.
Real-world usage
- Building office and campus Wi-Fi networks.
- Diagnosing an associated client that has no IP address or cannot reach a service.
Common mistakes
- Assuming an SSID alone proves a secure authenticated network.
- Confusing Wi-Fi association with successful DHCP, routing, or DNS.
- Ignoring channel interference and airtime contention when measuring throughput.
Interview questions
What is the basic role of an access point?
It connects wireless stations to a wired network, managing radio association and bridging traffic according to its configuration.
Why may Wi-Fi throughput vary even when signal strength looks good?
Airtime contention, interference, retransmissions, channel width, client capabilities, and AP load all affect throughput.