CompTIA Network+ (N10-009)Network ImplementationHard
A wireless network engineer selects a 5GHz channel in the UNII-2 band for a new access point deployment. The access point must comply with regulatory requirements for this frequency range in most countries. Which feature must the access point support to legally operate on this channel?
- AChannel bonding to combine adjacent channels for radar avoidance
- BWPA3-Enterprise authentication to encrypt all radar signal detection frames
- CMU-MIMO to allow multiple simultaneous radar detection streams
- DDynamic Frequency Selection (DFS) to detect and avoid interference with radar systems
Show answer & explanationAnswer & explanation
Correct answer: D. Dynamic Frequency Selection (DFS) to detect and avoid interference with radar systems
UNII-2 and UNII-2 Extended channels in the 5GHz band overlap with frequencies used by weather and military radar systems. Regulatory bodies require access points to support Dynamic Frequency Selection (DFS), which monitors for radar signals and vacates or avoids the channel if radar is detected, to prevent interference.
Why the other options are wrong
- A. Channel bonding increases bandwidth but does not address regulatory radar detection requirements.
- B. WPA3-Enterprise is an authentication/encryption method unrelated to radar detection.
- C. MU-MIMO improves throughput but has no role in radar avoidance.
Dynamic Frequency Selection (DFS)
A regulatory requirement for 5GHz UNII-2/UNII-2e channels that requires APs to detect radar signals and switch channels to avoid interference with radar systems.
- Required on UNII-2 and UNII-2 Extended bands
- AP must vacate channel if radar detected
- Can cause brief service interruption during channel switch
Memory trick: Radar's coming — DFS jumps ship to a clear channel.