Wireless Networking and Radio Fundamentals
Wireless as a Shared Medium
Radio basics
Wireless networks send bits over radio frequencies instead of copper or fiber. Because the medium is shared, signal quality, interference, and contention strongly affect performance.
Wireless tradeoff
Wi-Fi offers flexibility and mobility, but it is more sensitive to distance, walls, interference, and competing transmitters than wired Ethernet.
SSID, channels, and roaming
An SSID identifies a Wi-Fi network, while channels help separate transmissions in frequency space. Clients may roam between access points when signal quality changes.
Wi-Fi concepts
| Concept | Why it matters |
|---|---|
| SSID | Network name visible to clients |
| Channel | Frequency slot used for transmission |
| Access point | Bridges wireless clients to the wired LAN |
| Roaming | Move between APs without losing connectivity |
Why do wireless networks often use CSMA/CA rather than CSMA/CD?
Wireless nodes usually cannot reliably detect collisions while transmitting, so they try to avoid them.
Correct answer: Collision detection is hard in radio environments
What is the role of an access point in a Wi-Fi network?
The access point is the bridge and control point for the WLAN cell.
Correct answer: It connects wireless clients to the wired network and coordinates wireless access
Wired vs Wireless
Wired Ethernet
- More stable latency and throughput
- Less interference
- Requires physical cabling
Wi-Fi
- Mobility and convenience
- Shared radio spectrum
- More variable performance
What does roaming refer to in Wi-Fi?
Roaming is the transition of a client across AP coverage areas.
Correct answer: Moving a client between access points
Improving Wi-Fi performance
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1
Step 1: Place access points to reduce dead zones.
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Step 2: Choose channels to minimize overlap and interference.
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Step 3: Verify signal strength and client density.
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Step 4: Separate high-demand areas with additional APs.