How to Mitigate 2.4 GHz Co-Channel Interference in High-Density WLAN?
A network consultant must create a wireless design with these characteristics: • Provide coverage in a single contiguous space. • Support dual-band wireless coverage. • Use nine APs for full coverage in a 5 GHz band. What must the engineer do to mitigate co-channel interference and maintain coverage in 2.4 GHz?
Community Votes
100% of anonymous learners picked answer C. Votes are pick records left by other test-takers — they are not the verified answer.
Community Insight
It tests high-density band planning: with only three non-overlapping 2.4 GHz channels, keeping all nine 2.4 GHz radios active causes co-channel interference even though 5 GHz needs nine APs.
This high-density Cisco wireless design question asks how to mitigate 2.4 GHz co-channel interference when nine APs are needed for 5 GHz coverage in one contiguous space. The page establishes that selectively disabling 2.4 GHz radios (C) preserves 2.4 GHz coverage while reducing co-channel interference.
A frequent mistake is choosing static 2.4 GHz channel and power settings (B); static plans cannot overcome the three-channel limit with nine APs and may create coverage holes or persistent co-channel interference.
Community Discussion (3 comments)
Comments & Corrections
No comments yet — spotted an error or have a note? Share it below.
Expert Analysis
Why the Answer Is Correct
The scenario requires nine APs to cover a single contiguous space in 5 GHz, but 2.4 GHz has only three non-overlapping channels. Enabling all nine 2.4 GHz radios would force heavy channel reuse and co-channel interference. Disabling 2.4 GHz radios on selected APs reduces the number of 2.4 GHz cells while the remaining radios still provide the needed 2.4 GHz coverage because 2.4 GHz propagates farther. This is a standard high-density design tactic: not every AP must radiate on both bands.Why the Other Options Are Wrong
A TPC neighbor threshold of -64 dBm on 2.4 GHz can influence power adjustments but does not solve the fundamental shortage of non-overlapping channels with nine APs. Static channel and power settings (B) may produce a clean-looking plan on paper, but with nine APs on three channels the reuse distance still causes co-channel interference, and static settings cannot adapt to coverage changes. Deactivating low data rates (D) can shrink the 2.4 GHz cell, which may mitigate interference but risks creating coverage holes in a single contiguous space, contrary to the requirement to maintain 2.4 GHz coverage.Community Comment Notes
Bandito selected C and wrote, "C looks more like an right answer here." Jonycici simply stated "C is correct," agreeing with the selective disabling approach. ShamsDimashki selected B yet also wrote "The given answer is correct," which highlights why learners should reason from the three-channel 2.4 GHz limit rather than from static tuning alone. The community's strong C vote aligns with the high-density design doctrine, but the reasoning above is the decisive factor.Official Reference
Exam Strategy
When a high-density scenario mentions a 5 GHz AP count and asks about 2.4 GHz, first count the three non-overlapping 2.4 GHz channels and ask whether every AP really needs a 2.4 GHz radio. In a single contiguous space, selective 2.4 GHz radio disabling preserves coverage while reducing co-channel interference.
Frequently Asked Questions
Why disable 2.4 GHz radios instead of configuring static channel and power settings?
With nine APs in one space, 2.4 GHz has only three non-overlapping channels, so static settings cannot eliminate co-channel reuse. Disabling selected 2.4 radios reduces active cells while remaining APs cover the area.
Does deactivating low data rates solve 2.4 GHz co-channel interference here?
It can shrink the 2.4 GHz cell and reduce interference, but it may create coverage holes. The question requires maintaining 2.4 GHz coverage, so selective radio disabling is the better design choice.