The IEEE 802.11 family of standards defines wireless LAN (Wi-Fi) protocols. Each generation improves speed, range, and efficiency:
| Standard | Wi-Fi Name | Frequency | Max Speed | Year |
|---|---|---|---|---|
| 802.11b | Wi-Fi 1 | 2.4 GHz | 11 Mbps | 1999 |
| 802.11a | Wi-Fi 2 | 5 GHz | 54 Mbps | 1999 |
| 802.11g | Wi-Fi 3 | 2.4 GHz | 54 Mbps | 2003 |
| 802.11n | Wi-Fi 4 | 2.4 / 5 GHz | 600 Mbps | 2009 |
| 802.11ac | Wi-Fi 5 | 5 GHz | 3.5 Gbps | 2013 |
| 802.11ax | Wi-Fi 6 | 2.4 / 5 / 6 GHz | 9.6 Gbps | 2019 |
| 802.11be | Wi-Fi 7 | 2.4 / 5 / 6 GHz | 46 Gbps | 2024 |
| Feature | 2.4 GHz | 5 GHz |
|---|---|---|
| Range | Longer (better wall penetration) | Shorter |
| Speed | Lower | Higher |
| Congestion | More crowded (shared with Bluetooth, microwaves) | Less crowded |
| Channels | 3 non-overlapping (1, 6, 11) | 23+ non-overlapping |
| Best for | Large areas, IoT devices, long range | High-speed streaming, gaming, dense environments |
WPA3 improvements over WPA2:
| Protocol | Encryption | Key Exchange | Vulnerability |
|---|---|---|---|
| WEP (1997) | RC4 (40-bit) | Shared key | Easily cracked - deprecated |
| WPA (2003) | TKIP | PSK or 802.1X | TKIP vulnerabilities - deprecated |
| WPA2 (2004) | AES-CCMP (128-bit) | PSK or 802.1X | KRACK attack, dictionary attacks on PSK |
| WPA3 (2018) | AES-GCMP (192-bit) | SAE (Dragonfly) | More resistant to offline dictionary attacks |
Bluetooth is a short-range wireless technology for personal area networks (PAN). It operates in the 2.4 GHz ISM band using frequency hopping spread spectrum (FHSS).
| Version | Max Speed | Range | Key Feature |
|---|---|---|---|
| Bluetooth 4.0 (BLE) | 1 Mbps | 50 m | Low Energy - IoT, wearables |
| Bluetooth 5.0 | 2 Mbps | 240 m | 4x range, 2x speed vs 4.0 |
| Bluetooth 5.3 | 2 Mbps | 240 m | Improved coexistence, energy efficiency |
| Technology | Frequency | Range | Speed | Use Case |
|---|---|---|---|---|
| Zigbee | 2.4 GHz | 10-100 m | 250 Kbps | Smart home, IoT sensors, low power |
| Z-Wave | 908 MHz | 30 m | 100 Kbps | Smart home automation |
| NFC | 13.56 MHz | < 20 cm | 424 Kbps | Contactless payments, access cards |
| RFID | Various | cm to meters | Low | Asset tracking, inventory, access control |
| 4G LTE | 700 MHz-2.6 GHz | Cellular | ~150 Mbps | Mobile broadband |
| 5G | Sub-6 GHz / mmWave | Cellular | ~10 Gbps | Ultra-fast mobile, IoT, autonomous vehicles |
Client device
-> local network interface
-> default gateway or switch
-> routing/security decision
-> destination service
For Wireless, explain each hop by naming the address, protocol, port, and decision made at that layer.AP-East: channel 1, 20 MHz, moderate transmit power
AP-West: channel 11, 20 MHz, moderate transmit power
Target overlap: enough for roaming, not enough for both APs to dominate the same desks
Validation: measure RSSI, retries, channel utilization, and roam time while walking the intended path.More transmit power can worsen contention and roaming; a channel and coverage survey provides better evidence.
Signal strength does not show interference, channel congestion, retries, client capability, airtime contention, or upstream bottlenecks. Many clients can share one access point with strong signal while competing for limited airtime.
2.4 GHz generally travels farther and penetrates obstacles better, so it can be more reliable at distance. It also has fewer non-overlapping channels and more interference. 5 GHz usually offers more capacity and cleaner channels but shorter practical range.
WPA3 improves wireless authentication and cryptographic protection, but authorized credentials still grant network access. Shared passwords can spread beyond intended users and are difficult to revoke individually.
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