CBT - Certified Broadcast Technologist Broadcast Networking Basics Questions and Answers

Question 1

A broadcast facility is implementing a new IP-based video system to distribute a single live camera feed to 25 separate monitoring destinations within the plant. Which IP transmission method is the MOST efficient for this purpose?

Accepted Answer

Multicast

Answer

Multicast is the most efficient method because the source sends a single packet stream to a specific multicast group address. Network switches then intelligently replicate the stream only to the ports connected to devices that have requested to join that group, saving significant bandwidth compared to other methods.

Question 2

Which of the following statements best describes the fundamental principle of the SMPTE ST 2110 suite of standards for professional media over IP networks?

Accepted Answer

It separates video, audio, and ancillary data into individual, independently-timed essence streams over IP.

Answer

The core concept of SMPTE ST 2110 is the separation of video, audio, and ancillary data into individual 'essence' streams. Each stream is independently packetized and timed using Precision Time Protocol (PTP), which provides immense flexibility in routing and processing signals within a production environment.

Question 3

In a broadcast IP network carrying real-time video and audio, what is the primary function of Quality of Service (QoS)?

Accepted Answer

To assign priority to critical media traffic, ensuring low latency and minimizing packet loss.

Answer

Quality of Service (QoS) is used to manage network traffic by prioritizing certain types of data over others. In a broadcast network, real-time video and audio streams are extremely sensitive to delays (latency) and packet loss. QoS ensures these critical media packets are handled before less time-sensitive traffic (like file transfers), guaranteeing the performance needed for a stable on-air signal.

Question 4

A broadcast engineer is setting up a new SMPTE ST 2110 facility. What is the critical role of the Precision Time Protocol (PTP / IEEE 1588) in this environment?

Accepted Answer

To provide a high-accuracy, common time reference for synchronizing all separate media essence streams.

Answer

In an ST 2110 system, video and audio are separate IP streams. Precision Time Protocol (PTP) is essential for providing a highly accurate master clock reference to all devices on the network. This allows the separate essence streams to be precisely aligned and synchronized at their destination, which is the IP-based equivalent of traditional black burst or tri-level sync.

Question 5

When streaming live, real-time video over a managed IP network, why is the User Datagram Protocol (UDP) typically preferred over the Transmission Control Protocol (TCP) for transporting the media packets?

Accepted Answer

TCP's guaranteed delivery mechanism introduces latency that is unacceptable for live video.

Answer

TCP guarantees the delivery of every packet by requiring acknowledgements and retransmitting lost packets. This process of waiting for acknowledgements and retransmissions adds significant delay (latency), which would cause a live stream to pause or buffer. UDP, by contrast, sends packets without requiring acknowledgement, prioritizing speed and low latency over guaranteed delivery. For live video, it is better to have a momentary, imperceptible glitch from a dropped packet than to have the entire stream halt.

(CBT) Certified Broadcast Technologist Practice Test

(CBT) Certified Broadcast Technologist Practice Test

CBT - Certified Broadcast Technologist Broadcast Networking Basics Questions and Answers