2.2 Wireless Networking

Question 1

2.4 GHz Band

Answer 1

The 2.4 GHz band provides longer range but slower speeds than 5 GHz and 6 GHz.
It penetrates walls better but is more prone to interference because many devices use it (microwaves, cordless phones, Bluetooth).
Only three non-overlapping channels exist (1, 6, 11 in the U.S.).

Think:
Longer range, more interference, slower speeds.

Question 2

5 GHz Band

Answer 2

The 5 GHz band provides faster speeds and more available channels than 2.4 GHz.
It has shorter range and less wall penetration.
Less interference than 2.4 GHz.

Think:
Faster, cleaner, shorter range.

Question 3

6 GHz Band

Answer 3

The 6 GHz band (Wi-Fi 6E and newer) provides very high speeds and many non-overlapping channels.
Even shorter range than 5 GHz.
Very low interference (for now).

Think:
Newest, fastest, shortest range.

Question 4

Wireless Channels

Answer 4

A channel is a specific frequency range within a wireless band used for communication.
Overlapping channels cause interference and slow performance.

Question 5

Non-Overlapping Channels (2.4 GHz)

Answer 5

In the U.S., the safe non-overlapping channels are:
1, 6, and 11

CompTIA loves this fact.

Question 6

Channel Width

Answer 6

Channel width (20 MHz, 40 MHz, 80 MHz, etc.) determines how much bandwidth is available.
Wider channels = higher speeds but more potential interference.
Narrower channels = slower but more stable.

Question 7

Regulatory Domains

Answer 7

Wireless channels and power levels are regulated by government authorities (e.g., FCC in the U.S.).
Not all countries allow the same channels.

Question 8

802.11a

Answer 8

5 GHz

Up to 54 Mbps

Older standard

Question 9

802.11b

Answer 9

2.4 GHz

Up to 11 Mbps

Very old

Question 10

802.11g

Answer 10

2.4 GHz

Up to 54 Mbps

Backward compatible with 802.11b

Question 11

802.11n (Wi-Fi 4)

Answer 11

2.4 GHz and 5 GHz

Up to 600 Mbps

Introduced MIMO

Question 12

802.11ac (Wi-Fi 5)

Answer 12

5 GHz only

Multi-gigabit speeds

Improved MIMO

Question 13

802.11ax (Wi-Fi 6)

Answer 13

2.4 GHz and 5 GHz

Improved efficiency

Better performance in crowded environments

Question 14

Wi-Fi 6E

Answer 14

Uses 6 GHz band

High throughput

Low congestion

Question 15

Bluetooth

Answer 15

Bluetooth is a short-range wireless technology used for device-to-device communication (headsets, keyboards, speakers).
Operates in the 2.4 GHz band.
Low power consumption.

Range:

Class 2 (most common) ≈ 10 meters

CompTIA may test interference with Wi-Fi since both use 2.4 GHz.

Question 16

🔹 NFC (Near-Field Communication)

Answer 16

NFC is a very short-range wireless technology (a few centimeters).
Used for:

Contactless payments

Device pairing

Access control badges

Requires close physical proximity.

Question 17

🔹 RFID (Radio-Frequency Identification)

Answer 17

RFID uses radio waves to identify tagged objects.
Used in:

Inventory tracking

Security badges

Asset management

Does not require direct contact like NFC, and can operate at longer distances.

Question 18

2.4 GHz vs 5 GHz

Answer 18

2.4 GHz → Longer range, slower, more interference
5 GHz → Faster, shorter range, less interference

Question 19

5 GHz vs 6 GHz

Answer 19

6 GHz → Even faster, more channels, shortest range

Question 20

Bluetooth vs NFC

Answer 20

Bluetooth → Short range (meters), device communication
NFC → Very short range (centimeters), tap-to-pay

Question 21

NFC vs RFID

Answer 21

NFC → Very short range, secure pairing
RFID → Longer range tracking technology

Question 22

WiFi Exam Pattern Insight

Answer 22

CompTIA frequently asks scenario questions like:

“User in crowded apartment building has slow Wi-Fi” → Likely 2.4 GHz interference

“Need faster speeds in same room” → Switch to 5 GHz

“Tap phone to pay” → NFC

“Warehouse tracking system” → RFID