WLAN
WLAN (Wireless Local Area Network) is a technology that allows devices to connect to a local network and communicate wirelessly using radio waves (typically Wi-Fi) instead of physical cables. It provides the same core functions as a traditional wired LAN (data sharing, resource access, internet connectivity) but with the flexibility of mobility.
Core Purpose
Section titled “Core Purpose”- Replace/Eliminate Cables: Connects devices (laptops, smartphones, IoT devices, printers) within a limited area (home, office, campus) without Ethernet cables.
- Extend Network Access: Complements wired networks, providing connectivity where cabling is impractical.
Key Components
Section titled “Key Components”- Access Point (AP):
The central hardware device that broadcasts wireless signals. APs connect to a wired router/switch and act as a bridge between wireless clients and the wired network.- Example: Home Wi-Fi routers have built-in APs.
- Wireless Clients:
Devices with Wi-Fi adapters (e.g., laptops, smartphones, smart TVs). - Wireless Controller (Enterprise):
Manages multiple APs in large deployments (e.g., campuses, offices), handling configuration, security, and roaming. - Radio Waves:
Transmit data over frequencies (2.4 GHz, 5 GHz, or 6 GHz bands) using standards like IEEE 802.11 (Wi-Fi).
How WLAN Works
Section titled “How WLAN Works”- Association: A client device discovers nearby APs via their SSID (network name) and connects using authentication (e.g., password).
- Data Transmission:
Data is converted into radio signals, transmitted between clients and the AP, then routed to the wired network or other wireless devices. - Roaming: Clients automatically switch between APs as they move, maintaining connectivity (managed by protocols like 802.11r/k/v).
Standards & Protocols (Wi-Fi Generations)
Section titled “Standards & Protocols (Wi-Fi Generations)”| Standard | Common Name | Max Speed | Frequency Bands | Key Features |
|---|---|---|---|---|
| 802.11b | Wi-Fi 1 | 11 Mbps | 2.4 GHz | Legacy |
| 802.11a | Wi-Fi 2 | 54 Mbps | 5 GHz | Less interference |
| 802.11g | Wi-Fi 3 | 54 Mbps | 2.4 GHz | Backward-compatible |
| 802.11n | Wi-Fi 4 | 600 Mbps | 2.4/5 GHz | MIMO, 40 MHz channels |
| 802.11ac | Wi-Fi 5 | 3.5 Gbps | 5 GHz | Wider channels, MU-MIMO |
| 802.11ax | Wi-Fi 6/6E | 9.6 Gbps | 2.4/5/6 GHz | OFDMA, TWT, higher efficiency |
| 802.11be | Wi-Fi 7 | 40 Gbps | 2.4/5/6 GHz | 320 MHz channels, Multi-Link Operation |
Security in WLAN
Section titled “Security in WLAN”- Encryption:
- WEP (Insecure): Deprecated due to vulnerabilities.
- WPA/WPA2/WPA3: Modern protocols using AES encryption.
- WPA3 adds stronger encryption, protection against brute-force attacks, and “forward secrecy.”
- Authentication:
- PSK (Pre-Shared Key): Password-based (used in homes).
- 802.1X/RADIUS: Enterprise-grade authentication (e.g., username/password, certificates).
WLAN vs. LAN
Section titled “WLAN vs. LAN”| Feature | WLAN (Wireless LAN) | LAN (Wired Ethernet) |
|---|---|---|
| Medium | Radio waves (Wi-Fi) | Ethernet cables (copper/fiber) |
| Mobility | High (no cables) | Limited (fixed locations) |
| Speed/Latency | Lower (shared medium) | Higher (dedicated links) |
| Security | More vulnerable (eavesdropping) | More physically secure |
| Deployment | Flexible, scalable | Infrastructure-intensive |
Common Use Cases
Section titled “Common Use Cases”- Home/Office Networks: Internet access, printing, file sharing.
- Public Hotspots: Airports, cafes, hotels.
- IoT Connectivity: Smart home devices, sensors.
- Campus-Wide Coverage: Universities, hospitals.
Challenges
Section titled “Challenges”- Interference: From other Wi-Fi networks, Bluetooth devices, or microwaves (especially in 2.4 GHz).
- Coverage Dead Zones: Physical obstructions (walls, metal) weaken signals.
- Security Risks: Eavesdropping, rogue APs, brute-force attacks.
- Bandwidth Sharing: Performance degrades as more clients connect.
Analogy
Section titled “Analogy”Think of a WLAN as a “wireless office phone system”:
- Access Point (AP) = The base station broadcasting signals.
- SSID = The phone system’s name (e.g., “Company_Phones”).
- Clients = Cordless handsets connecting to the base.
- Roaming = Moving between rooms while keeping the call active.
- Encryption = Securing conversations so eavesdroppers can’t listen.
In short: WLAN frees devices from cables using Wi-Fi technology, balancing flexibility with trade-offs in speed and security. It’s the invisible backbone of modern mobile connectivity!