CCTV Network and IP Video 3 — Questions and Answers
Question 1: What is the purpose of Quality of Service (QoS) settings on a network switch used in an IP camera system?
- Encrypt video streams end-to-end
- Prioritize video traffic to prevent packet loss and latency (Correct answer)
- Assign static IP addresses to cameras
- Limit bandwidth consumed by non-camera devices
Correct answer: Prioritize video traffic to prevent packet loss and latency
QoS prioritizes video traffic in the network queue, reducing dropped packets and jitter that degrade live and recorded video quality.
Question 2: An IP camera is configured with a static IP of 192.168.1.50 but the NVR subnet is 10.0.0.0/24. What is the most likely result?
- The camera will auto-negotiate a new IP
- The camera will not be discoverable by the NVR without routing (Correct answer)
- The camera will use DHCP as a fallback
- The NVR will assign a compatible IP automatically
Correct answer: The camera will not be discoverable by the NVR without routing
Devices on different subnets cannot communicate directly without a router, so the camera will be unreachable from the NVR.
Question 3: Which H.264 profile provides the best compression efficiency with widest device compatibility for IP surveillance?
- Baseline Profile
- Main Profile
- High Profile (Correct answer)
- Extended Profile
Correct answer: High Profile
High Profile offers the best compression efficiency in H.264, reducing storage and bandwidth needs while maintaining quality.
Question 4: What distinguishes unicast streaming from multicast streaming in an IP camera system?
- Unicast sends one stream per viewer; multicast sends one stream to multiple viewers simultaneously
- Multicast uses TCP while unicast uses UDP
- Unicast requires more bandwidth per stream than multicast when there are multiple viewers
- Both A and C are correct (Correct answer)
Correct answer: Both A and C are correct
Unicast creates separate streams for each client, consuming more bandwidth as viewers increase, while multicast sends a single stream that multiple clients join.
Question 5: What is the recommended maximum cable run for Cat6 Ethernet in an IP camera installation without a repeater?
- 50 meters
- 100 meters (Correct answer)
- 150 meters
- 300 meters
Correct answer: 100 meters
IEEE 802.3 specifies a maximum segment length of 100 meters (328 feet) for Cat5e/Cat6 Ethernet.
Question 6: Which method allows an installer to discover ONVIF-compliant IP cameras on a local network without knowing their IP addresses?
- Ping broadcast
- WS-Discovery (Correct answer)
- SNMP polling
- DNS lookup
Correct answer: WS-Discovery
WS-Discovery is the ONVIF-specified mechanism that allows devices to announce themselves and be found on a local network.
Question 7: A 4MP IP camera streams at 15 fps using H.265. Compared to using H.264 at the same resolution and frame rate, storage requirements will typically be:
- About the same
- About 50% higher
- About 50% lower (Correct answer)
- About 75% lower
Correct answer: About 50% lower
H.265 (HEVC) achieves approximately 50% better compression than H.264 at equivalent quality, cutting storage requirements roughly in half.
CCTV Network and IP Video 3
What is the purpose of Quality of Service (QoS) settings on a network switch used in an IP camera system?