802.11 standards - Learn Tech From Zero

2.2 Explain wireless networking technologies

📘CompTIA A+ Core 1 (220-1201)

The 802.11 standards are a set of rules that define how Wi-Fi (wireless networking) works. These rules are created by the IEEE (Institute of Electrical and Electronics Engineers). Each standard improves speed, frequency, and features of Wi-Fi networks.

Think of 802.11 as the “version” of Wi-Fi that tells devices how to talk to each other over wireless networks.

1. 802.11a

Frequency: 5 GHz
Maximum Speed: 54 Mbps
Range: Shorter than 2.4 GHz (walls and obstacles reduce range more)
Use in IT: Often used in offices with many Wi-Fi networks because 5 GHz is less crowded. Devices like office laptops connecting to APs (Access Points) may use this standard to avoid interference.
Key point: Faster, but shorter range and less wall penetration.

2. 802.11b

Frequency: 2.4 GHz
Maximum Speed: 11 Mbps
Range: Longer than 5 GHz, better through walls
Use in IT: Older devices or IoT devices (like printers or barcode scanners) might still use 802.11b because it has longer range.
Key point: Slow but good coverage; more prone to interference because many devices (microwaves, Bluetooth) also use 2.4 GHz.

3. 802.11g

Frequency: 2.4 GHz
Maximum Speed: 54 Mbps
Range: Similar to 802.11b
Use in IT: Common in older office Wi-Fi networks; supports faster speeds while using 2.4 GHz.
Key point: Backward compatible with 802.11b.

4. 802.11n (Wi-Fi 4)

Frequency: 2.4 GHz and 5 GHz (dual-band)
Maximum Speed: Up to 600 Mbps
Range: Longer than 802.11g, improved with MIMO
MIMO: Stands for Multiple Input, Multiple Output, meaning multiple antennas send and receive data simultaneously.
Use in IT: Modern offices or data centers; supports multiple users and devices like laptops, IP phones, and wireless access points.
Key point: Much faster and reliable; can use both frequency bands.

5. 802.11ac (Wi-Fi 5)

Frequency: 5 GHz only
Maximum Speed: Up to several Gbps (theoretical 3.5 Gbps)
Technology: Uses MU-MIMO (Multi-User MIMO)
MU-MIMO: Allows an access point to communicate with multiple devices at the same time instead of one by one.
Use in IT: High-speed office Wi-Fi, video conferencing, cloud services, and high-bandwidth applications.
Key point: Fast, reliable, good for many devices at once.

6. 802.11ax (Wi-Fi 6)

Frequency: 2.4 GHz and 5 GHz, some support 6 GHz (Wi-Fi 6E)
Maximum Speed: Up to 9.6 Gbps (theoretical)
Technology: OFDMA (Orthogonal Frequency Division Multiple Access) – divides channels to serve multiple devices efficiently.
Target: High-density environments like offices with hundreds of devices or conference rooms.
Use in IT: Supports many users and devices simultaneously without slowing down network performance. Ideal for Wi-Fi in corporate campuses or schools.
Key point: Optimized for performance in busy networks.

Important Concepts for the Exam

Frequency Bands
- 2.4 GHz → Longer range, slower speed, more interference
- 5 GHz → Shorter range, faster speed, less interference
- 6 GHz → Newest, faster, and less crowded
Speed vs. Range
- Higher speeds usually have shorter range (5 GHz > 2.4 GHz in speed but shorter range).
Backward Compatibility
- Newer standards usually work with older devices (e.g., Wi-Fi 5 works with Wi-Fi 4 devices).
MIMO & MU-MIMO
- MIMO: Multiple antennas for better speed
- MU-MIMO: Multiple devices served at the same time
Channel Use
- 2.4 GHz has fewer channels, more interference
- 5 GHz has more channels, less interference

Quick Exam Tip Table

Standard	Frequency	Max Speed	Key Feature	IT Use
802.11a	5 GHz	54 Mbps	Less interference	Office networks
802.11b	2.4 GHz	11 Mbps	Long range	Older devices, IoT
802.11g	2.4 GHz	54 Mbps	Backward compatible	Legacy networks
802.11n	2.4/5 GHz	600 Mbps	MIMO, dual-band	Modern office Wi-Fi
802.11ac	5 GHz	3.5 Gbps	MU-MIMO	High-speed office Wi-Fi
802.11ax	2.4/5/6 GHz	9.6 Gbps	OFDMA, high density	Crowded enterprise networks

This summary gives your students a clear view of all 802.11 standards, their frequencies, speeds, and IT applications—everything needed to pass the exam.