N10-009 Question 316
Single answer5.4 Given a scenario, troubleshoot common performance issues.A network administrator receives complaints that users in one office suite experience very slow file transfers to a local server every afternoon. Voice calls and access to internet websites remain mostly unaffected. The suite connects through a single access switch uplink to the distribution switch. The administrator checks the switch and sees that the uplink interface shows a very high utilization rate during the slowdown periods, while CRC errors and interface drops remain near zero. Which action is the MOST appropriate next step to address the performance issue?
- A
Replace the uplink cable because CRC errors indicate a Layer 1 fault
- B
Increase available bandwidth on the uplink, such as upgrading the link speed or adding a higher-capacity connection
- C
Change the clients from DHCP to static addressing to reduce broadcast traffic
- D
Reboot the access switch each afternoon to clear the interface counters
Show answer and explanation
Correct answer: B
Explanation
The key troubleshooting clues are that the problem is time-based, limited to one office suite, affects file transfers much more than voice or general web access, and corresponds with very high utilization on the access switch uplink. That pattern strongly suggests a congestion or bandwidth bottleneck rather than a physical-layer fault. In real environments, this can occur when user backups, large file sync jobs, or scheduled transfers run during business hours. Standard vendor guidance and network performance best practices recommend examining interface utilization, error counters, and traffic patterns to distinguish congestion from faulty media. Because CRC errors and drops are near zero, there is little evidence of cable damage or duplex mismatch. The most appropriate next step is to increase available capacity on the uplink or redesign traffic flow to reduce oversubscription.
- A. Incorrect.
This is incorrect because the scenario explicitly states that CRC errors remain near zero. CRC errors commonly suggest cabling, duplex, or physical-layer problems, but those symptoms are not present here. Replacing the cable would not be the best next step when the primary indicator is sustained high utilization on the uplink.
- B. Correct.
This is correct because the evidence points to bandwidth saturation or congestion on the uplink. High utilization during the affected period, combined with low CRC errors and low interface drops, indicates the link is likely becoming a bottleneck rather than failing physically. Increasing uplink capacity or otherwise relieving the congestion is the most appropriate response to a throughput-related performance issue.
- C. Incorrect.
This is incorrect because changing from DHCP to static addressing would not meaningfully address slow file transfers caused by a heavily utilized switch uplink. While broadcasts can affect performance in some environments, DHCP traffic is typically minimal compared to file transfer traffic, and the scenario specifically identifies the uplink as highly utilized during the problem window.
- D. Incorrect.
This is incorrect because rebooting the switch does not solve the underlying congestion problem. Interface counters can help diagnose issues, but clearing them by rebooting would remove useful troubleshooting data and create unnecessary disruption. Best practice is to resolve the identified bottleneck rather than temporarily resetting equipment.