CCNA Network Infrastructure and Connectivity Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  802.11ac uses OFDMA, while 802.11ax uses only OFDM.

  Why it's wrong here

  That statement reverses the actual evolution. 802.11ac relies on conventional OFDM, allocating the entire channel to a single user at a time. 802.11ax introduces OFDMA, which partitions each channel into smaller subcarrier groups (resource units) so multiple clients can transmit concurrently, improving spectral efficiency and reducing overhead, especially in dense environments.

• ✓

  802.11ax supports 1024-QAM modulation, whereas 802.11ac supports up to 256-QAM.

  Why this is correct

  802.11ax increases the maximum modulation order to 1024-QAM, encoding 10 bits per subcarrier symbol, whereas 802.11ac caps at 256-QAM, encoding 8 bits per symbol. This yields a raw data rate increase of roughly 25% at equivalent channel width and coding rate, but only when signal-to-noise ratio is sufficient to support the denser constellation without excessive bit errors.

• ✗

  Both 802.11ac and 802.11ax operate exclusively in the 5 GHz band.

  Why it's wrong here

  This is incorrect because 802.11ax was designed to support both the 2.4 GHz and 5 GHz bands, while 802.11ac was defined for the 5 GHz band exclusively. The dual-band support in 802.11ax allows upgrades of legacy 2.4 GHz networks and improves efficiency in dense deployments, whereas 802.11ac's single-band limitation avoided the congested 2.4 GHz spectrum but reduced flexibility.

• ✓

  802.11ax operates in both the 2.4 GHz and 5 GHz bands, while 802.11ac operates only in the 5 GHz band.

  Why this is correct

  802.11ac was specifically engineered to operate exclusively within the 5 GHz radio frequency band, leveraging its wider channels and reduced interference for higher throughput. In contrast, 802.11ax was designed from the outset to provide improved performance and efficiency across both the 2.4 GHz and 5 GHz bands, making it more versatile for diverse environments. This fundamental difference in supported frequency bands is a core distinction between the two Wi-Fi standards, satisfying the question's requirement to describe a correct difference.

• ✗

  802.11ac introduces target wake time (TWT) for improved power saving, but 802.11ax does not support it.

  Why it's wrong here

  This statement gets the technology generation backwards. Target Wake Time (TWT) is a key power-saving feature introduced in 802.11ax, enabling stations to schedule negotiated wake times and sleep between exchanges, which reduces contention and battery drain. 802.11ac did not include TWT; instead it relied on earlier power-save mechanisms like PS-Poll or U-APSD, making the claim false.

Option-by-option analysis

Why each answer is right or wrong

Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.

Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”