220-1101 - Networking (20% of the exam) - Section 2.3

Compare and contrast protocols for wireless networking, including 802.11 standards, frequencies, channels, and Bluetooth, RFID, and NFC.

Compare the 802.11 wireless standards (a/b/g/n/ac/ax) by their supported frequency band (2.4 GHz, 5 GHz, 6 GHz) and throughput, and recognise the channel-overlap problem on 2.4 GHz. Distinguish long-range fixed wireless from short-range protocols - Bluetooth, RFID, and NFC - and match each to its typical use case.

802.11 standards2.4 GHz vs 5 GHzWi-Fi channelsRFID and NFC

Practice question for this objective

Free sampleNetworkingmedium

Users in an open-plan office complain that their 802.11ac laptops keep dropping to slow speeds even beside the access point. A technician finds the AP is broadcasting on both bands and clients are attaching to the 2.4 GHz radio. Which single change best improves their throughput?

  • ASwitch the affected clients to the 5 GHz band, which offers wider channels and less congestion for 802.11ac Correct
  • BMove all clients to the 2.4 GHz band, which travels further and therefore sustains faster speeds
  • CSet the 2.4 GHz radio to a 40 MHz channel width to double the available bandwidth per client
  • DDisable the 5 GHz radio so every device shares one band and roaming decisions become simpler
Recognise that 802.11ac clients gain throughput on the wider, less congested 5 GHz band rather than the longer-range 2.4 GHz band. The 5 GHz band offers many more non-overlapping channels and supports the channel bonding 802.11ac relies on, whereas 2.4 GHz is limited to three clear channels and cannot carry ac, so steering clients to 5 GHz recovers speed.

Why A is correct: 802.11ac operates on 5 GHz, which provides more non-overlapping channels and wider bonded channels, so moving clients there restores the higher throughput the standard is capable of.

Why B is wrong: 2.4 GHz does reach further, but it is more congested and cannot run 802.11ac, so it lowers rather than raises throughput for these clients.

Why C is wrong: Wider channels can raise throughput, but 40 MHz in the crowded 2.4 GHz band usually increases interference and still cannot deliver 802.11ac rates.

Why D is wrong: Simplifying to one band sounds tidy, but disabling 5 GHz removes the very band 802.11ac needs and forces everyone onto the slower, busier 2.4 GHz radio.

See more 220-1101 practice questions, answers explained.

Exam traps in Networking

Answers that look right on this material and are not. Each one is a distractor from a different question in the 220-1101 bank for this domain.

  • 802.11n, which introduced MIMO and can use both 2.4 GHz and 5 GHz bands

    Why it is wrong: 802.11n does support 5 GHz and MIMO, but its top rates are well below Wi-Fi 5 and it is branded Wi-Fi 4, so it does not meet the highest-throughput requirement.

  • 802.11g, which reaches 54 Mbps by using only the 2.4 GHz band for its channels

    Why it is wrong: Tempting because g does hit 54 Mbps, but g operates solely in 2.4 GHz, not 5 GHz, so it is the opposite band.

  • It replaces the 2.4 GHz radio with a faster wired backhaul for each connected client

    Why it is wrong: Wired backhaul is unrelated; 6E is about radio spectrum, and the 2.4 GHz radio is retained, not swapped out.

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