N10-009 Question 320
Single answerA network administrator is troubleshooting wireless issues on a corporate office floor with several access points. Users report that their laptops disconnect briefly while walking between conference rooms during VoIP calls, even though the SSID remains visible and signal strength appears adequate in most areas. A site survey shows the APs are using the same SSID and security settings, but some APs are configured with different mobility and roaming-related settings. Which of the following is the MOST likely cause of the problem?
- A
Channel bonding is disabled on the 5 GHz radios, reducing throughput during roaming
- B
The APs have a roaming misconfiguration that is preventing seamless client handoff between access points
- C
The WLAN is using WPA2 instead of WPA3, which causes clients to disconnect when they move
- D
The APs are experiencing PoE power negotiation issues that only occur when clients change locations
Show answer and explanation
Correct answer: B
Explanation
This scenario points to roaming misconfiguration. In a properly designed wireless LAN, multiple APs can share the same SSID, authentication method, and VLAN mappings so clients can move between coverage areas with minimal interruption. If mobility domain, controller-based roaming parameters, fast roaming settings, or other handoff-related configurations are inconsistent, clients may briefly disassociate or fully reauthenticate during movement, which is especially noticeable during latency-sensitive applications such as VoIP. Best practices from enterprise wireless design guidance emphasize consistent SSID, security, RF tuning, and roaming-related settings across APs participating in the same mobility environment. The symptoms here are not most consistent with throughput limits, encryption version choice alone, or PoE issues; they specifically indicate a handoff problem between APs.
- A. Incorrect.
This is incorrect. Disabling channel bonding on 5 GHz may reduce maximum throughput, but it does not typically cause brief disconnections specifically when users move between AP coverage areas. Roaming problems are more directly tied to handoff behavior, RF design, and roaming configuration consistency rather than channel width alone.
- B. Correct.
This is correct. The key clues are that users disconnect while moving, the SSID remains visible, signal is generally adequate, and the APs have inconsistent mobility/roaming settings. In an enterprise WLAN, mismatched roaming-related configuration can disrupt client transitions between APs, leading to call drops or brief disassociations during movement.
- C. Incorrect.
This is incorrect. WPA2 does not inherently cause client disconnects during movement. While security configuration must match across APs for a seamless user experience, simply using WPA2 instead of WPA3 is not a normal cause of roaming-related disconnections. The issue described points to inconsistent roaming behavior, not an outdated but still valid security standard.
- D. Incorrect.
This is incorrect. PoE power problems can cause AP instability, radio shutdowns, or degraded performance, but the scenario specifically ties the issue to users walking between rooms and notes inconsistent roaming-related settings. That makes roaming misconfiguration a much more likely root cause than a power negotiation issue.