VoIP - Voice Over IP MCQs

VoIP - Voice Over IP MCQs

Our team has conducted extensive research to compile a set of VoIP - Voice Over IP MCQs. We encourage you to test your VoIP - Voice Over IP knowledge by answering these 80+ multiple-choice questions provided below.
Simply scroll down to begin!

1: What is the full form of 3DES?

A.   Triple Decoding Encoding Standard

B.   Triple Data Encryption Standard

C.   Triple Data Encoding Standard

D.   Triple Digital Encryption Service

2: What is the full form of BGP?

A.   Border Gateway Protocol

B.   Border Gateway Police

C.   Border Global Position

D.   Border Global Protocol

3: What is the full form of POTS?

A.   Public Old Telephone Service

B.   Plain Old Telephone Service

C.   Plain Old Telecommunication System

D.   Protocols Of Telecommunication System

4: What is the full form of L2TP?

A.   Level 2 Technology Protocol

B.   Level 2 Transmission Protocol

C.   Layer 2 Transport Protocol

D.   Layer 2 Tunneling Protocol

5: What are the functions of Call Control?

A.   Call setup

B.   Call maintenance

C.   Call termination

D.   All of the above

6: What is the full form of CCS?

A.   Conditional Channel Signaling

B.   Combined Channel Signaling

C.   Common Channel Signaling

D.   Collective Channel Signaling

7: What is the function of D (Data) channel in ISDN?

A.   It is used for carrying data

B.   It is used for carrying voice

C.   It is used for carrying signaling information

D.   All of the above

8: Which TCP port number is used by H.323 protocol for call setup?

A.   5060

B.   1720

C.   1718

D.   2727

9: What is the full form of DSL?

A.   Digital Subscription Line

B.   Digital Super Link

C.   Digital Speed Line

D.   Digital Subscriber Line

10: What is a soft phone?

A.   It is a hardware phone especially made for VoIP

B.   It is a software that works on a laptop, desktop or a pocket PC

C.   It is the traditional phone that we use these days

D.   None of the above

11: What is the full form of DPNSS?

A.   Dedicated Private Network Signaling Services

B.   Digital Public Network Signaling System

C.   Dual Primary Network System Signaling

D.   Digital Private Network Signaling System

12: Is it possible to transport fax and modem traffic over a VoIP network?

A.   Yes

B.   No

13: What is the full form of SS7?

A.   Secure Signal 7

B.   Secure System 7

C.   Signaling System 7

D.   Switch Signal 7

14: What is the full form of TDM?

A.   Time Division Multiplexing

B.   Telephone Domain Management

C.   Transmission Division Multiplexing

D.   Time Domain Multiplexing

15: Which protocol provides end-to-end delivery services for data that requires real-time support such as interactive voice and video?

A.   Real-time Transport Protocol (RTP)

B.   Resource Reservation Protocol (RSVP)

C.   Compressed Real-time Transport Protocol (CRTP)

D.   Real-time Transport Control Protocol (RTCP)

16: What is the full form of PSTN?

A.   Public Switched Telephone Network

B.   Packet Service of Telephone Network

C.   Plain Switched Telephone Network

D.   Public Subscriber Trunk Network

17: What is the length of IP v4 addresses (in bits)?

A.   16 bits

B.   32 bits

C.   48 bits

D.   64 bits

18: Which of the following is used by an exchange to convert analog audio to digitized audio?

A.   SS7

B.   PCM


D.   DSL

19: Which of the following signaling protocols is based on the ISDN Q.931 standard?

A.   Q.933A



D.   SS7

20: Which of the following ITU standards delivers faxed documents as e-mail attachments over a VoIP netwok?

A.   T.30

B.   T.37

C.   T.38

D.   All of the above

21: How many voice conversations are possible on an E1 line simultaneously?

A.   16

B.   24

C.   30

D.   32

22: According to the OSI model, which layer performs the function of transforming bits of data into electrical signals and sending those signals across the media?

A.   Network

B.   Data Link

C.   Transport

D.   Physical

23: How many bits are there in a Class B address in Net ID (Network portion) and Host ID (Host Portion) fields by default?

A.   Net ID=8 bits & Host ID=24 bits

B.   Net ID=16 bits & Host ID=16 bits

C.   Net ID=24 bits & Host ID=8 bits

D.   None of the above

24: Which layer of the TCP/IP model ensures the quality and deliverability of VoIP packets?

A.   Application

B.   Transport

C.   Internetwork

D.   Physical

25: Which of the following are types of address signaling?

A.   TDM

B.   Pulse dialing


D.   FDM

26: Which of the following signaling protocols can be used with gateways over a VoIP network?

A.   SIP

B.   H.264

C.   H.323


27: Which of the following is responsible for electrical echo on telephone networks?

A.   Speakerphones

B.   Impedance mismatch

C.   Incorrect voltage

D.   All of the above

28: Which of the following provide transport security by using encryption, data integrity and data authentication?

A.   VPNs

B.   Firewalls

C.   Antivirus

D.   IPSec


State whether true or false:

Stateful firewalls do not remember the previous traffic that has occurred earlier in the session





30: Which of the following is the most common trunk signal type used by E&M signaling?

A.   Wink-start

B.   Immediate-start

C.   Delay-start

D.   Loop-start

31: What is the range of the frequency of a telephone channel?

A.   10 Hz to 9000 Hz

B.   300 Hz to 3400 Hz

C.   200 Hz to 20000 Hz

D.   16 Hz to 1600 Hz

32: Which of the following are the components of local loop signaling?

A.   Supervisory Signaling

B.   Address Signaling

C.   Trunk Signaling

D.   All of the above

33: Which of the following is one of the most important things common in all IP phones?

A.   Global Positioning System (GPS)

B.   Bluetooth

C.   Network Interface Card (NIC)

D.   None of the above

34: Which of the following are the major VoIP protocols?

A.   SIP

B.   H.323



E.   FTP

F.   RTP


35: What do you call a medium which allows multiple channels?

A.   Multi mode

B.   Single mode

C.   Broadband

D.   Baseband

36: Which of the following methods is most commonly used to remove echo in telephone networks these days?

A.   Echo Avoidance

B.   Echo Suppression

C.   Echo Cancellation

D.   All of the above

37: What is the minimum bandwidth required for VoIP to deliver high quality services?

A.   32 kbps

B.   64 kbps

C.   128 kbps

D.   256 kbps

38: Which of the following statements regarding CRTP is/are false?

A.   CRTP is usually used on slow links i.e. links that have a speed less than 2 Mbps

B.   Enabling CRTP does not add up to processing overhead

C.   Enabling compression on both sides of the link is not required

D.   CRTP can be used to conserve bandwidth on a WAN interface

E.   CRTP is not recommended to be used on fast links i.e. links that have a speed more than 2 Mbps

39: According to the ITU standard G.114, what is the maximum delay acceptable for high quality voice?

A.   100 ms

B.   125 ms

C.   150 ms

D.   200 ms

40: Which of the following protocols are assigned ports for each voice call?

A.   RTP in transmit direction

B.   RTCP in transmit direction

C.   RTP in receive direction

D.   RTCP in receive direction

41: Which of the following classes are used for host addressing?

A.   Class A

B.   Class B

C.   Class C

D.   Class D

E.   Class E

F.   All of the above

42: What is the path of wires that connect the subscriber's telephone to the telephone company's switch located at the latter's central office known as?

A.   Trunk

B.   Local Loop

C.   Demarcation Point

D.   Point of Presence

43: Which of the following can be used to hide internal network addresses and allow several computers on LAN to simultaneously share the router's global IP address?


B.   Firewall

C.   NAT

D.   None of the above

44: Which of the following VoIP protocols define end-to-end call signaling methods?

A.   SIP


C.   RTP

D.   H.323

45: Which of the following is the reason for using UDP instead of TCP for voice transmission?

A.   UDP is more reliable as compared to TCP

B.   UDP is fast as compared to TCP

C.   UDP re-transmits any packet lost during transmission whereas TCP does not

D.   All of the above

46: Which of the following has the correct sequence (from the lowest layer to the highest)?

A.   Physical, Network, Data Link, Session, Transport, Presentation, Application

B.   Physical, Data Link, Network, Transport, Session, Presentation, Application

C.   Transport, Session, Data Link, Application, Presentation, Network, Physical

D.   Physical, Data Link, Network, Transport, Presentation, Session, Application


State whether true or false:

QSIG is implemented on PRI interfaces only.





48: Which of the following protocols is used in a VoIP call at the application layer of the TCP/IP model?

A.   NTP


C.   RTP

D.   All of the above

49: Which of the following statements are true regarding circuit-switched networks (POTS) and packet-switched networks?

A.   In POTS, if any line is down, a call cannot be made

B.   In POTS, the line never goes down

C.   In packet-switched networks, if any line goes down, the voice packets can still reach their destination by selecting the best alternate route from the available routes

D.   None of the above

50: For which of the following services is SS7 responsible?

A.   Basic call setup, management and tearing down of connections

B.   Call forwarding

C.   Calling party number display

D.   All of the above