A network administrator is troubleshooting severe latency and intermittent connectivity issues for users in an open-office environment. A recent site audit reveals three 802.11n wireless access points (APs) mounted on the same ceiling grid, operating on the 2.4 GHz band and configured on channels 1, 3, and 5. Which of the following identifies the primary cause of the wireless performance degradation, and what is the proper solution?
- Adjacent-channel interference caused by overlapping channel assignments; reconfigure the access points to use non-overlapping channels 1, 6, and 11.Cevap
- BDHCP scope exhaustion causing APIPA address assignment; expand the DHCP pool to accommodate additional wireless clients.
- CLack of inter-VLAN routing at Layer 3; enable subinterfaces on the default gateway router for each wireless channel.
- DAntenna polarization mismatch across the ceiling grid; replace the existing omnidirectional antennas with high-gain parabolic dish antennas.
Cevap
The primary cause is adjacent-channel interference caused by overlapping channel assignments; the access points should be reconfigured to non-overlapping channels 1, 6, and 11.
In the 2.4 GHz ISM band, channel center frequencies are separated by 5 MHz, while each 802.11 channel requires 20 MHz (or 22 MHz) of bandwidth. Consequently, channels 1, 3, and 5 overlap heavily in frequency spectrum, generating adjacent-channel interference (ACI). Reconfiguring the three access points to the standard non-overlapping channels (1, 6, and 11) eliminates frequency overlap and resolves throughput degradation.
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Anahtar Kavram
2.4 GHz Non-Overlapping Channel Selection and Frequency Overlap Troubleshooting
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