CCTV Network and IP Video 5 — Questions and Answers
Question 1: What is 'edge analytics' in the context of IP cameras?
- Storing video footage on an edge server rather than the cloud
- Running video analytics such as motion detection or object recognition directly on the camera's processor (Correct answer)
- Connecting cameras at the geographic edge of a network
- Using a GPU at the network edge to process streams from multiple cameras
Correct answer: Running video analytics such as motion detection or object recognition directly on the camera's processor
Edge analytics means the camera's onboard processor runs AI or analytical algorithms locally, reducing bandwidth and server load.
Question 2: Which IP addressing scheme is recommended for IP cameras to prevent address conflicts and dropouts?
- APIPA (Automatic Private IP Addressing)
- Dynamic DHCP with short lease times
- Static IP addressing or DHCP reservations (Correct answer)
- IPv6 link-local addresses only
Correct answer: Static IP addressing or DHCP reservations
Static IPs or DHCP reservations (binding MAC to a fixed IP) prevent cameras from changing addresses after a reboot or lease expiration.
Question 3: In H.264 video, what is an 'I-frame'?
- An incomplete frame missing pixel data
- A fully encoded reference frame containing complete image data (Correct answer)
- An interpolated frame generated between two keyframes
- An indexed frame used for fast seek operations only
Correct answer: A fully encoded reference frame containing complete image data
An I-frame (Intra-coded frame) is a self-contained full image that other frame types reference; it enables random-access playback.
Question 4: What does RTCP (Real-Time Control Protocol) provide in an IP video streaming system?
- Encrypts the RTP video payload
- Carries control and QoS feedback information alongside an RTP media stream (Correct answer)
- Replaces RTSP for camera discovery on local networks
- Provides authentication tokens for camera login
Correct answer: Carries control and QoS feedback information alongside an RTP media stream
RTCP works alongside RTP to deliver control information, including packet loss statistics and jitter measurements, enabling QoS monitoring.
Question 5: Which factor most directly determines how many IP cameras can share a single network switch port via a PoE splitter daisy-chain?
- The switch's PoE class (802.3af vs 802.3at)
- The total PoE wattage budget of the switch port (Correct answer)
- The IP subnet mask configured on the switch
- The VLAN count assigned to the port
Correct answer: The total PoE wattage budget of the switch port
Each PoE port has a maximum watt output; the total power draw of all daisy-chained cameras cannot exceed that port's wattage budget.
Question 6: A site uses 802.3bt (PoE++) switches. What maximum power per port does this standard support?
- 15.4 W
- 30 W
- 60 W
- 90 W (Correct answer)
Correct answer: 90 W
IEEE 802.3bt (PoE++) supports up to 90 watts per port (Type 4), enabling high-power devices like PTZ cameras and access points.
Question 7: What is the role of a 'Media Access Control' (MAC) address in an IP camera network?
- It is the camera's globally unique hardware identifier used at the data-link layer (Correct answer)
- It is the camera's logical network address assigned by DHCP
- It encrypts video frames before transmission on the network
- It is the port number used by the RTSP stream
Correct answer: It is the camera's globally unique hardware identifier used at the data-link layer
A MAC address is a hardware-burned, globally unique 48-bit identifier used by switches to direct frames at Layer 2 of the OSI model.
CCTV Network and IP Video 5
What is 'edge analytics' in the context of IP cameras?