200-301 Question 75
Single answerA network administrator is troubleshooting connectivity issues between two devices connected via an Ethernet link. The link is configured as point-to-point, but the devices are not able to communicate. Upon checking the switch logs, the administrator notices frequent collisions on the link. What is the most likely cause of this issue?
- A
The two devices are configured for half-duplex operation.
- B
The Ethernet cable used is of a lower category than required.
- C
The devices are connected to different VLANs on the switch.
- D
Auto-negotiation has failed, and the devices have mismatched duplex settings.
Show answer and explanation
Correct answer: A
Explanation
In a point-to-point Ethernet connection, collisions are rare unless the link is configured for half-duplex operation. Half-duplex mode forces devices to take turns transmitting, which can result in collisions when both attempt to send data simultaneously. Ensuring both devices are set to full-duplex typically resolves this issue.
- A. Correct.
Frequent collisions on a point-to-point Ethernet link typically occur when the devices are set to half-duplex. In a half-duplex configuration, devices cannot send and receive data simultaneously, leading to collisions.
- B. Incorrect.
While a lower-category Ethernet cable can cause poor performance or link failure, it does not directly result in collisions.
- C. Incorrect.
Devices on different VLANs cannot communicate unless routing or inter-VLAN communication is configured. However, this would not cause collisions.
- D. Incorrect.
Mismatched duplex settings (e.g., one device on half-duplex and the other on full-duplex) can cause poor performance and frame errors, but it does not directly lead to frequent collisions.