100-150 Question 185
Single answerA network administrator is troubleshooting connectivity issues within a LAN. They observe that devices connected to the same switch cannot communicate with each other. Upon inspection, the administrator finds that the switch has no VLAN configuration, but all devices are connected to the same switch ports. Which of the following could be the root cause of the issue?
- A
The switch ports are in a disabled state.
- B
The devices are on different IP subnets.
- C
The switch is operating in Layer 3 mode.
- D
The switch does not support VLANs.
Show answer and explanation
Correct answer: B
Explanation
In this scenario, devices connected to the same switch cannot communicate because they are on different IP subnets. VLANs do not come into play here since there are no VLAN configurations on the switch. Communication between different IP subnets requires routing, which is not possible with a basic Layer 2 switch. This is why the issue lies in the devices being on different subnets.
- A. Incorrect.
If the switch ports were disabled, the devices would not have any connectivity to the switch, and no communication would occur. This scenario specifies that devices are connected, making this option incorrect.
- B. Correct.
Devices on different IP subnets cannot communicate with each other unless a router or Layer 3 switch is present to route traffic between the subnets. In this scenario, the lack of a VLAN configuration does not affect the IP subnets, making this the correct answer.
- C. Incorrect.
Switches operating in Layer 3 mode provide additional routing capabilities but do not inherently block communication between devices on the same VLAN or subnet. This is not relevant to the scenario.
- D. Incorrect.
If the switch did not support VLANs, it would still function as a basic Layer 2 switch, allowing devices on the same subnet to communicate. This does not explain the root cause of the issue.