MCQs On Data Communication Services Part-1

1. Which of the following is/are the examples of data communication services.
i) SMDS  ii) Frame relay  iii) X.25  iv) ATM
A) i, ii and iv only
B) i, ii and iii only
C) i, iii and iv only
D) All i, ii, iii and iv only

2. ……………. was developed in 1970 by CCITT for providing an interface between public packet switched network and their customers.
A) SMDS
B) Frame relay
C) X.25
D) ATM

3. X.25 protocol is based on the protocols used in early ……………. networks such as ARPANET, DATAPAC, TRANSPAC etc.
A) Packet Switching
B) Circuit Switching
C) Virtual Packet Circuit Switching
D) Virtual Packet Switching

4. ……………. protocol is a physical layer protocol is used to specify the physical electrical and procedural interface between host and network.
A) X.25
B) X.21
C) SMDS
D) X.23

5. ……………… is a connection oriented service which supports switched virtual circuits as well as the permanent circuits.
A) X.25
B) X.21
C) SMDS
D) ATM

6. In X.25, ……………… is established between a computer and network when computer sends a packet to the network requesting to make a call a packet to the network requesting to make a call to other computer.
A) Virtual circuit
B) Switched circuit
C) Switched virtual circuit
D) Switched intelligent circuit

7. In order to allow the computers who do not use the X.25 to communicate with the …………………., a packet assembler disassembler (PAD) is used.
A) X.21
B) SMDS
C) Frame relay
D) X.25

8. The layers defined by X.25 interface is/are
i) physical layer  ii) data link layer  iii) packet layer  iv) application layer
A) i, ii and iv only
B) i, ii and iii only
C) i, iii and iv only
D) All i, ii, iii and iv only

9. The X.25 defines the interface for exchange of packets between the
user’s machine (DTE) and the packet switching node to which this DTE is
attached which is called as …….
A) DCE
B) DDE
C) DLC
D) HDL

10. At the physical level, …………… physical interface is being used which is defined for circuit switched data network.
A) X.25
B) X.21
C) Frame relay
D) SMDS


11. The virtual circuit service of X.25 provides for two types of virtual circuits which are ………….
i) virtual circuit  ii) permanent virtual circuit  iii) permanent virtual call  iv) virtual call
A) i and ii only
B) ii and iii only
C) iii and iv only
D) ii and iv only

12. A ………………….. is dynamically established virtual circuit using a call setup and call clearing procedure.
A) Permanent virtual circuit
B) Virtual call
C) Virtual circuit
D) Permanent virtual call

13. A ……………… is a fixed network assigned virtual where data transfer takes place as with virtual calls, but no call setup or clearing required.
A) Permanent virtual circuit
B) Virtual call
C) Virtual circuit
D) Permanent virtual call 

14. Which of the following is/are the advantages of X.25
i) Frame delivery is more reliable  ii) X.25 is faster than Frame relay  iii) Frames are delivered in order  iv) Flow control is provided

A) i, ii and iv only
B) i, ii and iii only
C) i, iii and iv only
D) All i, ii, iii and iv only

15. ……………… is a connection oriented service, which can be imagined to be equivalent to a virtual leased line.
A) X.25
B) Frame relay
C) SMDS
D) ATM

16. ………………. does not provide acknowledgements or normal flow control.
A) Frame relay
B) X.25
C) SMDS
D) ATM

17. ………….. was developed for taking the advantage of the high data rates and low error rates in the modern communication system.
A) X.25
B) Frame relay
C) SMDS
D) ATM

18. In …………….. the cell control packets are used for setting up and clearing virtual circuits.
A) ATM
B) X.25
C) SMDS
D) Frame relay

19. Which of the following is/are the advantages of frame relay.
i) streamlined communication process   ii) lower delay   iii) higher throughput
A) i and ii only
B) ii and iii only
C) i and iii only
D) All i, ii and iii

20. In ……………. the number of functions of a protocol at the user network interface is reduced. 
A) X.25
B) Frame relay
C) SMDS
D) ATM

Answers

1. D) All i, ii, iii and iv only
2. C) X.25
3. A) Packet Switching
4. B) X.21
5. A) X.25
6. C) Switched virtual circuit
7. D) X.25
8. B) i, ii and iii only
9. A) DCE
10. B) X.21
11. D) ii and iv only
12. B) Virtual call
13. A) Permanent virtual circuit
14. C) i, iii and iv only
15. B) Frame relay
16. A) Frame relay
17. B) Frame relay
18. D) Frame relay
19. D) All i, ii and iii
20. B) Frame relay