Telecommunications Voice over IP (VoIP) 1

Question 1

What protocol is most commonly used to initiate and terminate VoIP calls?

Accepted Answer

SIP

Answer

SIP (Session Initiation Protocol) is the dominant signaling protocol for establishing, modifying, and terminating VoIP sessions.

Question 2

What protocol carries the actual voice media in a VoIP call?

Accepted Answer

RTP

Answer

RTP (Real-time Transport Protocol) carries the encoded audio and video media streams during an active VoIP call.

Question 3

What is jitter in VoIP communications?

Accepted Answer

Variation in packet arrival times

Answer

Jitter is the variation in latency between consecutive voice packets, which causes audio quality issues if not buffered.

Question 4

Which codec is known for narrowband voice quality at 64 kbps?

Accepted Answer

G.711

Answer

G.711 is the standard PCM codec used in traditional telephony and VoIP, operating at 64 kbps with toll-quality audio.

Question 5

What is the recommended maximum one-way latency for acceptable VoIP call quality?

Accepted Answer

150 ms

Answer

ITU-T G.114 recommends a maximum one-way delay of 150 ms for acceptable conversational quality in VoIP.

Telecommunications Practice Test