802.11 Wireless Standards( Comptia Objective 2.4)

Question 1

What frequency does 802.11a operate at?

Answer 1

5 Ghz uses a 20mhz channel bandwidth.

Question 2

What frequency does 802.11b operate at?

Answer 2

2.4 Ghz and uses a 22mhz channel bandwidth

Question 3

What frequency does 802.11g operate at?

Answer 3

2.4 Ghz and uses a 20mhz channel bandwidth.

Question 4

What frequency does 802.11n operate at?

Answer 4

5 GHz and/or 2.4 Ghz

Question 5

What frequency does 802.11ac operate at?

Answer 5

5 Ghz and uses up to 160mhz channel bandwidth using dual 80mhz bonded channels.

• 80mhz channels however is the default bandwidth for each channel.

Question 6

What is the Maximum theoretical throughput of 802.11a?

Answer 6

54 Mbit/s

Question 7

What is the maximum theoretical throughput of 802.11b?

Answer 7

11 Mbit/s

Question 8

What is the maximum theoretical throughput of 802.11g?

Answer 8

54 Mbit/s

Question 9

What is the maximum theoretical throughput of 802.11n?

Answer 9

• 600 Mbit/s uses 20 or 40mhz channel widths and 4 antennas( 150mbit/s per stream)
• 802.11 N Wireless standard also introduced 4 MIMO
  Multiple- Input multiple output able to send multiple streams of data for greater throughput.

Question 10

What is the maximum theoretical throughput of 802.11ac?

Answer 10

6. 8 Gbit/s up to 160mhz channel bandwidth but uses 80mhz channel bandwidth by default.( Can use 40mhz for 802.11N stations)
   - Denser signaling modulation
   - Faster data transfers
   - Included 2 x the amount of MU-MIMO streams as 802.11N at 8 streams.

Question 11

What should you do when setting up a new wireless network to allow maximum throughput and prevent interference?

Answer 11

• You should investigate the airways using a Wi-Fi Analyzer to ensure there is no cross traffic between competing wireless routers. Make sure there is at least a 25mhz gap between channels and if not switch to a different channel

Question 12

What frequency does Zigbee IOT transmit data at?

Answer 12

• It transmits data similar to bluetooth over 2.4ghz and 900mhz also Zigbee Pro transmits data over 915mhz. It has a max range between 10-20 meters.

Question 13

What frequency does Z-Wave internet of things transmit data at?

Answer 13

• It transmits data within the 800-900mhz frequency.

Question 14

What IEEE standard does Zigbee Internet of Things use?

Answer 14

• Uses the IEEE 802.15.4PAN

- Is an alternative to Wifi and Bluetooth.

Question 15

What were the two types of 2G wireless networks?

Answer 15

• GSM Global system for Mobile communications

- CDMA Code division Multiple Access

Question 16

What is the supported download speed of 4G and LTE?

Answer 16

• 150mbits/s for 4G

- 300mbits/s for LTA-A

Question 17

When using 802.11 2.4ghz frequency what channels can be used while avoiding overlap?

Answer 17

• Channels 1, 6 and 11. Each channel uses 5mhz of frequency therefore to avoid overlap you would space each used channel at least 25mhz apart at minimum.

Question 18

When using 802.11 5ghz frequency what channels are also available while also avoiding overlap?

Answer 18

• Channels 36-48, 52-64, 100-144, 149-165 also using a minimum of 25mhz of space between channels.