Telecommunications Voice over IP (VoIP) 3

Question 1

What is the purpose of a jitter buffer in VoIP?

Accepted Answer

Store packets temporarily to reduce delivery variation

Answer

A jitter buffer temporarily stores incoming voice packets to compensate for network jitter and deliver smooth, consistent audio.

Question 2

Which QoS mechanism marks VoIP packets for priority treatment?

Accepted Answer

DSCP

Answer

DSCP (Differentiated Services Code Point) marks packets in the IP header to signal routers to give them priority treatment.

Question 3

What does MOS stand for in VoIP quality assessment?

Accepted Answer

Mean Opinion Score

Answer

MOS (Mean Opinion Score) is a numerical measure of voice call quality, rated from 1 (bad) to 5 (excellent).

Question 4

What is a SIP trunk?

Accepted Answer

A virtual connection linking a PBX to a carrier's SIP network

Answer

A SIP trunk is a virtual connection between an IP-PBX and an ITSP (Internet Telephony Service Provider) for making and receiving calls.

Question 5

What protocol is used for delivering voicemail notifications to IP phones?

Accepted Answer

NOTIFY via SIP

Answer

SIP NOTIFY messages are used to send message waiting indicator (MWI) notifications to IP phones about new voicemails.

Telecommunications Practice Test