Conference Call Web Conference Protocols 3

Question 1

In a large web conference, what is the role of an SFU (Selective Forwarding Unit)?

Accepted Answer

Forwards each participant's stream selectively without decoding

Answer

An SFU receives each stream once and forwards selected streams to participants without re-encoding, saving server CPU.

Question 2

How does an MCU (Multipoint Control Unit) differ from an SFU?

Accepted Answer

MCU decodes and mixes streams into a single composite

Answer

An MCU decodes incoming streams and mixes them into one composite stream, using more server resources than an SFU.

Question 3

What technique adjusts video quality dynamically when a participant's bandwidth drops?

Accepted Answer

Adaptive bitrate / simulcast

Answer

Simulcast and adaptive bitrate let the server send a lower-quality layer when bandwidth is constrained.

Question 4

Which mechanism helps a conference recover smoothly from lost packets in the audio stream?

Accepted Answer

Jitter buffer and PLC

Answer

A jitter buffer smooths timing variation while packet loss concealment fills gaps from missing audio packets.

Question 5

What does end-to-end encryption (E2EE) guarantee in a web conference?

Accepted Answer

Only participants can decrypt the media, not the relay server

Answer

With E2EE the media is encrypted so even the forwarding server cannot access the content.

Conference Call Practice Test