| WLAN 802.11 Wi-Fi Security Wireless Installation |
1. WLAN Key Characteristics
- Half-Duplex Transmission: Devices share the same frequency for sending and receiving
- Environmental Impact: Walls, water, and metals attenuate signals
- Higher frequencies → higher data rate, lower range | Lower frequencies → wider range, lower data rate
2. Wireless Standards Organizations
| Organization | Purpose |
|---|
| IEEE | Develops and maintains operational standards |
| FCC | Regulates wireless usage in the U.S. |
| ETSI | European telecommunications standards |
| Wi-Fi Alliance | Promotes device interoperability |
| WLANA | Educates consumers about WLANs |
3. IEEE 802.11 Standards
| Standard | Year | Frequency | Data Rate |
|---|
| 802.11b | 1999 | 2.4 GHz | 11 Mbps |
| 802.11a | 1999 | 5 GHz | 54 Mbps |
| 802.11g | 2003 | 2.4 GHz | 54 Mbps |
| 802.11n | 2010 | 2.4/5 GHz | Up to 300 Mbps |
| 802.11ac | 2013 | 5 GHz | Up to 1 Gbps |
| 802.11ax | 2021 | 2.4/5/6 GHz | Up to 9.6 Gbps |
4. Wi-Fi 5 vs Wi-Fi 6 Comparison
| Parameter | Wi-Fi 5 | Wi-Fi 6 |
|---|
| Frequency | 5 GHz | 2.4/5/6 GHz |
| Channel Width | Up to 160 MHz | Up to 160 MHz |
| Data Rate | Up to 3.5 Gbps | Up to 9.6 Gbps |
| Modulation | 256-QAM | 1024-QAM |
| User Capacity | 4 | 8 |
5. Cellular Technologies
| Generation | Bandwidth | Standard |
|---|
| 3G | 2 Mbps | WCDMA, CDMA-2000 |
| 4G/LTE | 200–1000 Mbps | LTE, WiMAX |
| 5G | Up to 10 Gbps | mmWave, MIMO |
6. WLAN Components
- WAP: Bridge between wireless devices and LAN
- NIC: Internal or USB wireless adapter
- Antennas:
- Omni-directional: 360° coverage
- Yagi (Directional): Long range, focused beam
7. WLAN Deployment Modes
- Ad Hoc: Direct device-to-device communication
- Infrastructure: Devices connect via AP to LAN
8. Wireless Controllers and AP Management
- Thick APs: Independently managed
- Thin APs: Centrally managed via WLC with CAPWAP
- VLAN Pooling: Helps reduce broadcast domain
9. Antenna Gain Units
dBi: Relative to an isotropic antenna
dBd: Relative to dipole antenna
dBd = dBi - 2.2
Examples:
Yagi 7 dBd → 9.2 dBi
Omni 4.8 dBd → 7 dBi
10. Site Survey
- Collect user and coverage requirements
- Identify obstacles and signal overlap
- Use tools like Ekahau or AirMagnet
- Optimize signal strength across floors
11. WLAN Security
Threats:
- Rogue APs
- Unmonitored Ad Hoc networks
- DoS attacks via jamming or spoofing
- Passive attacks like packet sniffing
Defenses:
- Use WLC with CAPWAP protocol
- Send Deauthentication frames
- Enable MFP (Management Frame Protection)
- Deploy Wireless IDS/IPS
Security Mechanisms:
- Open Access: Public networks (no encryption)
- WEP: Weak encryption, vulnerable
- WPA: Dynamic TKIP encryption
- WPA2: Strong AES-CCMP encryption (recommended)
- MAC Filtering: Device-based access control (spoofable)
- PSK: Shared password between AP and device
