Overview Of Wireless Networking
Wireless Networking – Introductory Lesson
1. Introduction to Wireless Networking
- Definition of Wi-Fi
- Stands for Wireless Fidelity
- Uses radio waves to provide wireless internet and network access
- How Wireless Networks Work
- Wireless routers have built-in radio transmitters
- Clients (laptops, smartphones, IoT devices) connect using Wi-Fi adapters
- Communication is established using the IEEE 802.11 standard
- The router transmits TCP/IP packets, which are received by devices and sent back
Analogy:
Think of Wi-Fi like a radio station broadcasting music. Your device (receiver) needs the correct frequency to tune in.
2. Wireless Standards
- Defined by the IEEE 802.11 family
- Uses Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) to prevent data collisions
- Comparison of Major IEEE 802.11 Standards:
| Standard | Frequency | Max Speed | Range | Notes |
| 802.11a | 5 GHz | 54 Mbps | Short | More non-overlapping channels |
| 802.11b | 2.4 GHz | 11 Mbps | Long | Prone to interference |
| 802.11g | 2.4 GHz | 54 Mbps | Long | Backward compatible with 802.11b |
| 802.11n | 2.4 & 5 GHz | 600 Mbps | Medium | Uses MIMO (Multiple Input Multiple Output) |
| 802.11ac | 5 GHz | 1 Gbps+ | Short | Uses MU-MIMO (Multi-User MIMO) |
| 802.11ax (Wi-Fi 6) | 2.4 & 5 GHz | 9.6 Gbps | Medium | Improves speed & efficiency |
Key Features:
- MIMO: Allows multiple antennas to send and receive data simultaneously
- Channel Bonding: Uses multiple channels at once to increase performance
- Backward Compatibility: New standards support older devices
3. Wireless Frequencies
| Parameter | 2.4 GHz Frequency | 5 GHz Frequency |
| Operating Standard | 802.11b/g/n | 802.11a/n/ac/ax |
| Speed | Slower | Faster |
| Distance | Longer | Shorter |
| Bandwidth | Lower | Higher |
| Use Case | General browsing, IoT devices | Streaming, gaming |
| Range | 150 ft (indoors), 300 ft (outdoors) | One-third of 2.4 GHz range |
Important Considerations:
- 2.4 GHz has better range but more interference (from microwaves, Bluetooth)
- 5 GHz has faster speeds but shorter range
4. Wireless Network Types
- Wireless Personal Area Network (WPAN)
- Example: Bluetooth, Zigbee
- Short-range (up to 30 ft) for wearables, smart devices
- Wireless Local Area Network (WLAN)
- Example: Home Wi-Fi, Office Wi-Fi
- Uses Wi-Fi routers and covers up to 300 ft
- Wireless Metropolitan Area Network (WMAN)
- Example: WiMAX, 4G LTE networks
- Covers cities or suburbs
- Wireless Wide Area Network (WWAN)
- Example: Cellular networks (3G, 4G, 5G)
- Provides long-distance connectivity
5. Wireless Topology
- Infrastructure Mode
- Uses Access Points (APs) as central controllers
- Provides better security & control
- Example: Home & enterprise Wi-Fi networks
- Ad-Hoc Mode
- Peer-to-peer communication without an AP
- Example: Bluetooth file sharing, temporary networks
- Mesh Topology
- Nodes (devices) connect dynamically
- Uses 802.11s standard
- Example: City-wide wireless networks, disaster relief
6. Wireless Site Design
- Service Set Identifier (SSID): The network name
- Broadcast Beacons: APs advertise SSID every 100ms
- Site Survey Considerations:
- Blueprint analysis
- Heat maps to analyze signal strength
- Identifying interference sources
7. Wireless Antennas
- Omni-Directional Antennas
- 360-degree coverage
- Used for home & office networks
- Unidirectional (Yagi) Antennas
- Point-to-point communication
- Used for long-distance connectivity
Key Technologies:
- MIMO: Increases capacity
- Beamforming: Directs signals toward devices
8. Extending Wireless Coverage
- Wireless Range Extenders (WREs)
- Repeats signals from the router
- Wireless Distributed Systems (WDS)
- Uses multiple APs connected wirelessly
- Wireless Controllers
- Fat APs: Function independently
- Thin APs: Require a central controller
9. Troubleshooting Wireless Issues
| Issue | Cause | Solution |
| Signal Loss | Distance, interference | Move device closer, use range extender |
| AP Not Working | Faulty update | Restart & check firmware |
| Wrong Channel | Overlapping networks | Use 1, 6, or 11 in 2.4 GHz |
| Authentication Issues | Wrong password | Re-enter credentials, check encryption settings |
Factors Affecting Wireless Signals:
- Physical Objects (walls, metal)
- RF Interference (microwaves, cordless phones)
- Electrical Interference (lights, fans)
10. Wireless Security & Hacking Threats
- War Driving: Searching for unsecured Wi-Fi
- War Chalking: Marking vulnerable networks
- Evil Twin Attack: Rogue AP mimicking real AP
- Deauthentication Attack: Forces clients off network
- IV Attack: Cracks WEP encryption
- Bluetooth Attacks:
- Bluejacking: Sends spam messages
- Bluesnarfing: Steals data
11. Wireless Authentication & Encryption
Authentication Methods:
| Method | Description |
| Open Authentication | No password required |
| WEP | Insecure, easily cracked |
| MAC Filtering | Only allows specific MAC addresses |
| PSK (Pre-Shared Key) | Shared password |
| 802.1X/EAP | Secure authentication using certificates |
Encryption Standards:
| Standard | Encryption | Notes |
| WEP | RC4 | Weak, outdated |
| TKIP | RC4 + MIC | Temporary fix |
| AES | Strong encryption | Used in WPA2 |
WPA vs. WPA2:
| Feature | WPA | WPA2 |
| Encryption | TKIP | AES |
| Security | Moderate | High |
| Speed | Slower | Faster |
12. Conclusion
- Wireless networking improves mobility and convenience
- Security is crucial to prevent hacking
- Best Practices:
- Use WPA2 or WPA3
- Hide SSID if needed
- Change default router passwords
- Use non-overlapping channels
- Perform regular site surveys