hardMultiple Choice
220-1201 Practice Question: A network administrator is troubleshooting…
A network administrator is troubleshooting intermittent connectivity issues on a fiber optic link between two buildings. The link works but has occasional errors. The technician inspects the fiber and finds that the connectors are dirty. After cleaning them, the issue persists. What should the technician check next?
⚠ Common exam trap
The trap here is that candidates might jump to replacing hardware (cable or SFPs) without first measuring the optical signal, but the exam expects you to know that verifying the light level with a power meter is the logical next step after cleaning connectors.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Check the light level with a power meter.
After cleaning the connectors, the next logical step is to verify the optical signal strength using a power meter. Dirty connectors are a common cause of intermittent errors, but if cleaning doesn't resolve the issue, the problem may be a weak or degraded optical signal due to other factors such as a damaged cable, faulty transceiver, or excessive loss. A power meter measures the actual light level (in dBm) and compares it to the transceiver's specifications, quickly identifying if the signal is too low. This is a standard troubleshooting step for fiber links and is more efficient than blindly replacing components.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Replace the entire fiber cable.
Why it's wrong here
Intermittent connectivity on a fiber link could stem from various causes, including dirty connectors, faulty transceivers, or signal attenuation. Replacing an entire fiber cable, especially one spanning between buildings, is a highly disruptive, costly, and time-consuming procedure. It should only be considered as a final troubleshooting step after more targeted and less invasive diagnostics, such as power meter readings and transceiver swaps, have failed to identify or resolve the problem.
- ✓
Check the light level with a power meter.
Why this is correct
Intermittent connectivity on a fiber link often indicates a problem with signal integrity, such as excessive attenuation or insufficient power. A fiber optic power meter measures the optical power transmitted through the cable, allowing the administrator to determine if the light signal is within acceptable parameters. Low light levels can point to issues like dirty connectors, tight bends, or a damaged cable, providing crucial diagnostic information before more drastic actions are taken.
- ✗
Swap the SFP modules on both ends.
Why it's wrong here
While faulty Small Form-Factor Pluggable (SFP) modules can certainly cause intermittent connectivity, swapping them without first assessing the optical power level introduces another variable without isolating the root cause. A power meter reading provides objective data about the cable's performance independent of the transceivers. If the light level is good, then swapping SFPs becomes a more logical next step to rule out transceiver failure.
- ✗
Run a loopback test on the switch ports.
Why it's wrong here
A loopback test is designed to verify the functionality of a network interface card (NIC) or a switch port by sending data out and immediately receiving it back, confirming the port's ability to transmit and receive. However, the problem description specifies "intermittent connectivity issues on a fiber link between buildings." This indicates the issue lies within the fiber optic cable or its associated transceivers, not necessarily the switch ports themselves, making a loopback test less relevant for diagnosing the fiber link's integrity.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
This 220-1201 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 220-1201 exam.