Users in a remote office are experiencing slow file transfers to the data center. The network technician runs a traceroute and discovers high latency on a specific hop. The technician pings that hop and gets replies with varying latency. The technician also checks the interface error counters on the router at that hop and finds no errors. What is the most likely cause?

Duplex mismatch

A duplex mismatch typically results in CRC errors and collisions, which are not present here.

Incorrect MTU

An MTU mismatch would cause fragmentation or packet drops, but the ping replies suggest the link is working with variable latency.

Route flapping

Route flapping would cause intermittent connectivity and unreachability, not consistently high latency.

What does this N10-009 question test?

Standard ACLs match source addresses.

What is the correct answer to this question?

The correct answer is: CPU overload on the router — High CPU utilization on a router can cause packet queuing delays, leading to variable latency without necessarily producing interface errors. This often happens when the router is overloaded with processing tasks such as ACLs, routing updates, or encryption. Duplex mismatch would show CRC errors, incorrect MTU would cause fragmentation issues, and route flapping would cause intermittent reachability.

What should I do if I get this N10-009 question wrong?

Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.