Wireless Networking

Lesson 4 · Wireless Networking · Download .docx

Objectives

Compare 802.11 wireless standards and their characteristics
Differentiate Wi-Fi security protocols from WEP to WPA3
Explain Bluetooth, BLE, and NFC use cases

Key terms

802.11ax: IEEE standard for Wi-Fi 6; introduces OFDMA for dense multi-client environments.
WPA3: Wi-Fi Protected Access 3 — strongest current Wi-Fi encryption, uses SAE handshake.
WPA2: Wi-Fi Protected Access 2 — AES/CCMP encryption; current minimum acceptable standard.
WEP: Wired Equivalent Privacy — broken RC4-based encryption; never use in production.
OFDMA: Orthogonal Frequency Division Multiple Access — serves multiple clients on same channel simultaneously.
SSID: Service Set Identifier — the human-readable name broadcasted by a wireless access point.
BSSID: Basic SSID — the MAC address of the access point; identifies a specific AP on a network.
WAP: Wireless Access Point — bridges 802.11 wireless to the wired Ethernet network.
2.4 GHz: Wi-Fi band with longer range but fewer non-overlapping channels and more congestion.
5 GHz: Wi-Fi band with shorter range but more channels and higher throughput.
Bluetooth Classic: Bluetooth for high-bandwidth audio (A2DP) and file transfers.
Wi-Fi Calling: Carrier feature routing phone calls over Wi-Fi when cellular signal is weak.

The concept

802.11 STANDARDS EVOLUTION

The 802.11 family has evolved through multiple generations. 802.11b/g operates on 2.4 GHz at up to 54 Mbps. 802.11n (Wi-Fi 4) introduced dual-band and MIMO for improved throughput. 802.11ac (Wi-Fi 5) brought MU-MIMO and 80/160 MHz channels on 5 GHz. 802.11ax (Wi-Fi 6) added OFDMA, which splits a single channel into smaller resource units that can be allocated to different clients simultaneously — dramatically improving performance in dense environments like classrooms and offices.

WI-FI SECURITY

WEP was the first Wi-Fi security standard but its RC4 implementation reuses initialization vectors predictably, allowing passive attackers to recover the key in minutes with freely available tools. WPA replaced WEP with TKIP but still has weaknesses. WPA2 uses AES/CCMP and remains the current minimum. WPA3 adds Simultaneous Authentication of Equals (SAE), which prevents offline dictionary attacks against captured handshakes — the vulnerability that cracks WPA2 passwords.

2.4 GHz vs. 5 GHz

The 2.4 GHz band has only three non-overlapping channels (1, 6, 11) and is shared with Bluetooth, microwaves, and baby monitors — creating heavy congestion. It penetrates walls and travels farther. The 5 GHz band has more non-overlapping channels, less congestion, and supports wider channel widths for higher throughput, but its signal attenuates faster over distance and through walls.

BLUETOOTH AND NFC

Bluetooth Classic (BR/EDR) supports profiles like A2DP (audio), OBEX (file transfer), and HFP (headset). BLE uses a completely different radio mode with 1 MHz channels and duty cycling to reduce power consumption by 10× or more. NFC operates at 13.56 MHz with a maximum range of about 4 cm; its defining use case is contactless payment where physical tap confirms the transaction intent.

Worked examples

Example 1: A coffee shop has 30 customers on Wi-Fi and everyone complains it is slow. Analysis: The router likely uses 2.4 GHz only, which has three non-overlapping channels. Recommendation: Upgrade to a Wi-Fi 6 router with OFDMA capability and enable 5 GHz. OFDMA can serve multiple clients per channel, reducing per-client latency in dense environments.

Example 2: A security audit finds WEP-encrypted guest network. Response: WEP is cryptographically broken and can be attacked in minutes. Immediately upgrade to WPA2 at minimum (WPA3 if hardware supports it). Change the SSID and pre-shared key. Document the finding and remediation in the change log.

Common mistakes

Using WEP because it is listed as an option in router settings — it is broken and must never be selected.
Confusing the SSID (network name) with the PSK (Wi-Fi password) — they are different settings.
Believing 2.4 GHz is always slower — it has less bandwidth, but range can be better in certain environments.
Confusing Bluetooth Classic (audio/files) with BLE (IoT/sensors) — they have different data rate capabilities.
Forgetting that Airplane Mode disables all radios — Wi-Fi and Bluetooth can be re-enabled manually afterward.

Self-check

Try each one before you look. A miss here costs nothing and tells you exactly what to reread.

1. Wi-Fi 6 is based on which IEEE standard?

2. Why should WEP never be used?

3. OFDMA in Wi-Fi 6 improves performance by:

4. The strongest current Wi-Fi encryption standard is:

5. Bluetooth Low Energy is primarily used for:

Canvas is the official record. This companion enhances the PGCC curriculum; it does not replace it. Last name and class year only. Students with a 504 plan or IEP: your accommodations apply.

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