CompTIA Network+ (N10-009)Network ImplementationMedium
A network technician is troubleshooting poor wireless performance in a densely populated office building. Users report frequent disconnections and slow speeds, especially during peak hours. The technician observes that many access points (APs) are configured to use the same channels in the 5GHz band, even if they are not directly overlapping. Which of the following is the most likely cause of the performance issues?
- AHigh signal-to-noise ratio (SNR) due to strong adjacent channel interference.
- BIncorrect WPA3 configuration leading to authentication delays.
- CInsufficient power over Ethernet (PoE) budget for the APs.
- DExcessive retransmissions caused by co-channel interference.
Show answer & explanationAnswer & explanation
Correct answer: D. Excessive retransmissions caused by co-channel interference.
In environments with many APs, using the same channels (co-channel interference) or overlapping channels (adjacent channel interference) can lead to devices having to retransmit data due to collisions or corrupted frames, significantly degrading wireless performance.
Why the other options are wrong
- A. High SNR is good; it means the signal is strong relative to noise. Low SNR is bad. Adjacent channel interference would also cause issues, but the scenario specifically mentions APs using the *same* channels, pointing to co-channel interference.
- B. WPA3 configuration issues would typically manifest as authentication failures or inability to connect, not specifically slow speeds and disconnections after connecting.
- C. Insufficient PoE budget would cause APs to fail to power on or operate intermittently, which is different from slow speeds and disconnections when APs are operating.
Co-channel Interference
Interference that occurs when multiple wireless devices or access points transmit on the same frequency channel within the same geographical area, leading to performance degradation due to increased collisions and retransmissions.
- Common in dense Wi-Fi deployments without proper channel planning.
- Causes include overlapping AP coverage using identical channels.
- Mitigated by careful channel planning, power adjustments, and proper AP placement.
Memory trick: Think of radio channels like lanes on a highway; too many cars in one lane causes traffic jams.