Users in a conference room frequently experience slow and dropping wireless connections. A site survey shows three other access points in the vicinity all using channel 6. Signal strength is adequate. What is the most likely cause?
Multiple APs on the same channel overlap, causing contention and retransmissions, which reduces throughput.
Why this answer
The correct answer is B because all three nearby access points are operating on channel 6, which causes co-channel interference. Even with adequate signal strength, overlapping basic service sets (BSSs) on the same channel lead to contention, increased collisions, and reduced throughput due to the CSMA/CA mechanism in 802.11 networks. This results in slow and dropping connections for users in the conference room.
Exam trap
The trap here is that candidates often assume signal strength is the only factor for wireless performance, but Cisco tests the understanding that co-channel interference can cause poor performance even with strong signals, especially when multiple APs share the same channel in a dense environment.
How to eliminate wrong answers
Option A is wrong because incorrect encryption settings (e.g., mismatched WPA2 keys) would prevent association or authentication entirely, not cause intermittent slow or dropping connections with adequate signal. Option C is wrong because an incorrect SSID configured would prevent clients from discovering or connecting to the network, not cause performance degradation after connection. Option D is wrong because low antenna gain on the access points would manifest as weak signal strength, but the site survey explicitly states signal strength is adequate, ruling out antenna gain issues.