220-1102 Question 315
Single answerVideo surveillanceA small retail store recently replaced its analog CCTV system with six IP cameras that record to a network video recorder (NVR). A week later, the owner reports that video from two cameras becomes choppy and occasionally stops during busy hours, while the other cameras continue recording normally. Those two cameras are the farthest from the network closet and are powered through the same PoE switch as the others. The technician confirms the NVR has enough storage and CPU capacity. Which action should the technician take FIRST to most likely resolve the issue?
- A
Lower the recording retention period on the NVR from 30 days to 14 days
- B
Check the network cabling run length and link speed for the affected cameras
- C
Replace the NVR with a model that has more drive bays
- D
Disable motion detection on all cameras to reduce storage writes
Show answer and explanation
Correct answer: B
Explanation
In a real-world IP video surveillance deployment, when only certain cameras exhibit choppy or dropped video, technicians should first isolate factors unique to those cameras. Here, the affected cameras are the farthest from the network closet, making cabling distance, connector quality, PoE stability, and negotiated link speed the most likely causes. Ethernet runs for copper are generally limited to 100 meters (328 feet), and marginal cabling can especially affect bandwidth-intensive devices like IP cameras. Best practice is to verify cable length, inspect terminations, check switch port statistics for errors or drops, confirm the cameras are linking at the expected speed, and validate that PoE power delivery is sufficient for each device. This aligns with common network troubleshooting methodology used in A+ Core 2 environments: verify the simplest and most probable physical-layer issue before replacing core equipment.
- A. Incorrect.
This is incorrect because retention period affects how long footage is kept, not whether two specific cameras become choppy during active use. The scenario already states that the NVR has sufficient storage and CPU resources, so reducing retention would not address intermittent stream quality from only the farthest cameras.
- B. Correct.
This is correct because the problem is isolated to the two cameras farthest from the network closet, which strongly suggests a physical network issue such as excessive cable length, poor terminations, marginal PoE delivery, or a link negotiating down to a lower speed. In IP video surveillance, cable quality, distance, and switch port status are common first troubleshooting points when only specific remote cameras show unstable video.
- C. Incorrect.
This is incorrect because additional drive bays increase storage capacity, not network transport reliability. Since only two cameras are affected and the NVR has already been verified to have enough storage and processing capability, replacing the recorder would be an unnecessary and unlikely fix.
- D. Incorrect.
This is incorrect because motion detection settings can reduce some processing and storage activity, but they would not typically cause only the two most distant cameras to fail during busy hours while the others remain stable. This option reflects the misconception that all surveillance performance problems are caused by recording load rather than by network or power delivery issues.