65 Computer Networks Questions with Answers


This post consists of approx. 65 questions from COMPUTER NETWORKS from previous years UGC NET papers. this will help you to understand the pattern of questions comes under this section. Generally 5 out 50 questions comes from COMPUTER NETWORKS. New syllabus issued by the NTA is given in this post. This post also highlight the questions from each years. Try to solve the questions.

Best of luck for your NTA UGC NET  preparation.


Computer Networks :
Network fundamentals :
Local Area Networks ( LAN ),
Metropolitan Area Networks ( MAN ),
Wide Area Networks ( WAN ),
Wireless Networks, Inter Networks.
Reference Models :
The OSI model,
TCP / IP model.
Data Communication :
Channel capacity.
Transmission media-
twisted pair,
coaxial cables,
fibre – optic cables,
wireless transmission-
infrared and
millimeter waves.
Lightwave transmission.
Thelephones – local loop,
narrowband ISDN,
broadband ISDN,
ATM, High speed LANS.
Cellular Radio.
Communication satellites-
geosynchronous and
Internetworking :
Switch / Hub,
Concatenated virtual circuits,
Routing :
Virtual circuits and
Routing algorithms.
Congestion control.
Network Security :
Cryptography-public key,
secret key.
Domain Name System ( DNS ) –
Electronic Mail and
Worldwide Web ( WWW ).
The DNS,
Resource Records,
Name servers.
E-mail-architecture and

Dec 2015

Q1. Which of the following services is not provided by wireless access point in 802.11 WLAN ?
(1) Association (2) Disassociation (3) Error correction (4) Integration

Q2. Which of the following fields in IPv 4 datagram is not related to fragmentation ?
(1) Type of service (2) Fragment offset (3) Flags (4) Identification

Q3. Four channels are multiplexed using TDM. If each channel sends 100 bytes/second and we multiplex 1 byte per channel, then the bit rate for the link is_______.
(1) 400 bps (2) 800 bps (3) 1600 bps (4) 3200 bps

Q4. In a typical mobile phone system with hexagonal cells, it is forbidden to reuse a frequency band in adjacent cells. If 840 frequencies are available, how many can be used in a given cell?
(1) 280 (2) 210 (3) 140 (4) 120

Q5. Using p = 3, q = 13, d = 7 and e = 3 in the RSA algorithm, what is the value of ciphertext for a plaintexts?
(1) 13 (2) 21 (3) 26 (4) 33
June 2015
Q6. Which of the following protocols is an application layer protocol that establishes, manages and terminates multimedia sessions ?
(1) Session Maintenance Protocol
(2) Real – time Streaming Protocol
(3) Real – time Transport Control Protocol
(4) Session Initiation Protocol

Q7. Match the following port numbers with their uses :
List-I List-II
(a) 23 (i) World wide web
(b) 25 (ii) Remote Login
(c) 80 (iii) USENET news
(d) 119 (iv) E-mail
Codes :
(a) (b) (c) (d)
(1) (iv) (i) (ii) (iii)
(2) (ii) (i) (iv) (iii)
(3) (ii) (iv) (iii) (i)
(4) (ii) (iv) (i) (iii)

Q8. Which of the following is not associated with the session layer?
(1) Dialog control
(2) Token management
(3) Semantics of the information transmitted
(4) Synchronization

Q9. What is the size of the ‘total length’ field in IPv 4 datagram ?
(1) 4 bits (2) 8 bits (3) 16 bits (4) 32 bits

Q10. Which of the following is/are restriction(s) in classless addressing ?
(1) The number of addresses needs to be a power of 2.
(2) The mask needs to be included in the address to define the block.
(3) The starting address must be divisible by the number of addresses in the block.
(4) All of the above

Dec 2014

Q11. The period of a signal is 10 ms. What is its frequency in Hertz ?
(A) 10 (B) 100
(C) 1000 (D) 10000

Q12. In a classful addressing, first four bits in Class A IP address is
(A) 1010 (B) 1100
(C) 1011 (D) 1110

Q13. Which of the following algorithms is not a broadcast routing algorithm ?
(A) Flooding (B) Multidestination routing
(C) Reverse path forwarding (D) All of the above

Q14. An analog signal has a bit rate of 6000 bps and a baud rate of 2000 baud. How many data elements are carried by each signal element ?
(A) 0.336 bits/baud (B) 3 bits/baud
(C) 120,00,000 bits/baud (D) None of the above

Q15. How many distinct stages are there in DES algorithm, which is parameterized by a 56-bit key ?
(A) 16 (B) 17
(C) 18 (D) 19

June 2014

Q16. Infrared signals can be used for short range communication in a closed area using propagation.
(A) ground (B) sky
(C) line of sight (D) space

Q17. A bridge has access to address in the same network.
(A) Physical (B) Network
(C) Datalink (D) Application

Q18. The minimum frame length for 10 Mbps Ethernet is _____ bytes. and maximum is____ bytes
(A) 64 & 128 (B) 128 & 1518
(C) 1518 & 3036 (D) 64 & 1518

Q19. The bit rate of a signal is 3000 bps. If each signal unit carries 6 bits, the baud rate of the signal is .
(A) 500 baud/sec
(B) 1000 baud/sec
(C) 3000 baud/sec
(D) 18000 baud/sec.
Q20. Match the following:
List-I List – II
a. Physical layer i Allow resources to network access
b. Datalink layer ii Move packets from one destination to other
c. Network layer iii. Process to process message delivery
d. Transport layer iv. Transmission of bit stream
e. Application Layer v. Formation of frames
a b c d e
(A) iv v ii iii i
(B) v iv i ii iii
(C) i iii ii v iv
(D) i ii iv iii v
Dec 2013
Q21.When data and acknowledgement are sent in the same frame, this is called as
(A) Piggy packing
(B) Piggy backing
(C) Back packing
(D) Good packing

Q22. Encryption and Decryption is the responsibility of Layer.
(A) Physical
(B) Network
(C) Application
(D) Datalink
Q23. An analog signal carries 4 bits in each signal unit. If 1000 signal units are sent per second, then baud rate and bit rate of the signal are and
(A) 4000 bauds \ sec & 1000 bps
(B) 2000 bauds \ sec & 1000 bps
(C) 1000 bauds \ sec & 500 bps
(D) 1000 bauds \ sec & 4000 bps

Q24. The VLF and LF bauds use propagation for communication.
(A) Ground (B) Sky
(C) Line of sight (D) Space

Q25. Using the RSA public key crypto system, if p = 13, q = 31 and d = 7, then the value of e is
(A) 101 (C) 105
(B) 103 (D) 107

June 2013

Q26. Which of the following addresses is used to deliver a message to the correct application program running on a host?
(A) Port
(B) IP
(C) Logical
(D) Physical

Q27. In substitution, a character in the plaintext is always changed to the same character in the ciphertext, regardless of its position in the text.
(A) polyalphabetic
(B) monoalphabetic
(C) transpositional
(D) multialphabetic

Q28. In classful addressing, the IF address belongs to
(A) Class A
(B) Class B
(C) Class C
(D) Class D

Q29. In hierarchical routing with 4800 routers, what region and cluster sizes should be chosen to minimize the size of the routing table for a threelayer hierarchy?
(A) 10 clusters, 24 regions and 20 routers
(B) 12 clusters, 20 regions and 20 routers
(C) 16 clusters, 12 regions and 25 routers
(D) 15 clusters, 16 regions and 20 routers

Q30. In IPv4 header, the field is needed to allow the destination host to determine which datagram a newly arrived fragments belongs to.
(A) identification
(B) fragment offset
(C) time to live
(D) header checksum

Dec 2012

Q31. The Mobile Application Protocol (MAP) typically runs on top of which protocol?
(A) SNMP (Simple Network Management Protocol)
(B) SMTP (Simple Mail Transfer Protocol)
(C) SS7 (Signalling System 7)
(D) HTTP (Hyper Text Transfer Protocol)

Q32. If a packet arrive with an M-bit value is ‘1’ and a fragmentation offset value ‘0’, then it is______ fragment.
(A) First
(B) Middle
(C) Last
(D) All of the above

Q33. The number of bit strings of length eight that will either start with a 1 bit or end with two bits 00 shall be
(A) 32
(B) 64
(C) 128
(D) 160

Q34. The design issue of Datalink Layer in OSI Reference Model is
(A) Framing
(B) Representation of bits
(C) Synchronization of bits
(D) Connection control

Q35. Data Encryption Techniques are particularly used for .
(A) protecting data in Data Communication System.
(B) reduce Storage Space Requirement.
(C) enhances Data Integrity.
(D) decreases Data Integrity.

June 2012

Q36. Networks that use different technologies can be connected by using
(A) Packets
(B) Switches
(C) Bridges
(D) Routers

Q37. Both hosts and routers are TCP/IP protocol software. However, routers do not use protocol from all layers. The layer for which protocol software is not needed by a router is
(A) Layer – 5 (Application)
(B) Layer – 1 (Physical)
(C) Layer – 3 (Internet)
(D) Layer – 2 (Network Interface)

Q38. Which of the following TCP/IP Internet protocol is diskless machine uses to obtain its IP address from a
server ?
(D) X.25

Q39. Decryption and encryption of data are the responsibility of which of the following layer ?
(A) Physical layer
(B) Data Link layer
(C) Presentation layer
(D) Session layer

Q40. In which circuit switching, delivery of data is delayed because data must be stored and retrieved from RAM ?
(A) Space division
(B) Time division
(C) Virtual
(D) Packet

Q41. In which Routing Method do all the routers have a common database ?
(A) Distance vector
(B) Link state
(C) Link vector
(D) Dijkestra method

Q42. Page Shift Keying (PSK) Method is used to modulate digital signal at 9600 bps using 16 level. Find the line signals and speed (i.e. modulation rate).
(A) 2400 bauds
(B) 1200 bauds
(C) 4800 bauds
(D) 9600 bauds
Hint: D = R/b or D = R/log2 L
where D= modulation rate in baud ; R data rate in bps; L number of different signal elements; b number of bits per signal element

Q43. The station to hub distance in which it is 2000 metres.
(A) 100 Base-Tx
(B) 100 Base-Fx
(C) 100 Base-T4
(D) 100 Base-T1
(D) None of the above

Q44. Mobile IP provides two basic functions.
(A) Route discovery and registration
(B) Agent discovery and registration
(C) IP binding and registration
(D) None of the above

Dec 2011

Q45. Hub is a term used with
(A) A Star Networks
(B) A Ring Networks
(C) A Router
(D) A Bridge

Q46. The amount of uncertainty in a system of symbol is called
(A) Bandwidth (B) Entropy (C) Loss (D) Quantum

Q47. Which of the following network access standard disassembler is used for connection station to a packet switched network ?
(A) X.3 (B) X.21 (C) X.25 (D) X.75

Q48. A station in a network in a network forward incoming packets by placing them on its shortest output queue. What routing algorithm is being used ?
(A) Hot potato routing
(B) Flooding
(C) Static routing
(D) Delta routing

Q49. Start and stop bits are used in serial communications for
(A) Error detection
(B) Error correction
(C) Synchronization
(D) Slowing down the communication

Q50. The number of bits required for an IPV 6 address is
(A) 16 (B) 32 (C) 64 (D) 128
June 2011

Q51. A comparison of frequency division and time division multiplexing system shows that
(A) FDM requires a lower bandwidth, but TDM has greater noise immunity.
(B) FDM has greater noise immunity and requires lower bandwidth than TDM.
(C) FDM requires channel synchronization, while TDM has greater noise immunity.
(D) FDM requires more multiplex while TDM requires band pass filter.

Q52. If carrier modulated by a digital bit stream, has one of the possible phase of 0, 90, 180 and 270 degrees, then modulation called

Q53. Consider the following statement :
(i) The bandwidth of the A.M., wave depends on the band width of the modulating signal.
(ii) The bandwidth of the A.M., wave depends on the modulation index.
(iii) The bandwidth of the F.M, wave for all practical purpose depends on the amplitude of the carrier.
Of these statements the correct statements are
(A) (i, ii)
(B) (i, iii)
(C) (ii, iii)
(D) All of the above

Q54. A smart modem can dial, hangup and answer incoming calls automatically. Can you tell who provides the appropriate instructions to the modem for this purpose ?
(A) Communication software
(B) Error detection protocols
(C) Link access procedure (LAP)
(D) Telecommunications

Q55. Which of the following switching techniques is most suitable for interactive traffic ?
(A) Circuit switching
(B) Message switching
(C) Packet switching
(D) All of the above

Dec 2010

Q56. Frequency shift keying is used mostly in
(A) Radio transmission
(B) Telegraphy
(C) Telephone
(D) None of the above

Q57. The baud rate is
(A) always equal to the bit transfer rate
(B) equal to twice the bandwidth of an ideal channel
(C) not equal to the signalling rate
(D) equal to half of the bandwidth of an ideal channel

Q58. How much bandwidth is there in 1 micron of spectrum at a wavelength of 1 micron ?
(A) 300 MHz
(B) 3 GHz
(C) 300 THz
(D) 30 KHz

Q59. Which of the following file transfer protocols use TCP and establishes two virtual circuits between the local and remote server ?

Q60. The threshold effect in demodulator is
(A) exhibited by all demodulator, when the input signal to noise ratio is low.
(B) the rapid fall on output signal to noise ratio when the input signal to noise ratio fall below a particular value.
(C) the property exhibited by all A.M. suppressed carrier coherent demodulator.
(D) the property exhibited by correlation receiver.

June 2010

Q61. The ______ field is the SNMP PDV reports an error in a response message.
(A) error index
(B) error status
(C) set request
(D) agent index

Q62. What does the URL need to access documents?
I. Path name
II. Host name
IV. Retrieval method
V. Server port number
(A) I, II, III (B) I, III, V (C) I, II, IV (D) III, IV, V

Q63. End-to-End connectivity is provided from Last-to-Last in
(A) Network layer
(B) Session layer
(C) Transport layer
(D) Data link layer

Q64. What services does the internet layer provide ?
1. Quality of service
2. Routing
3. Addressing
4. Connection oriented delivery
5. Framing bits
(A) 1, 2, 3 (B) 2, 3, 4 (C) 1, 3, 4, 5 (D) 2, 3, 4, 5

Q65. What is the maximum operating rate of a wireless LAN using infrared communication?
(A) 1 mbps (B) 2 mbps (C) 5 mbps (D) 11mbps


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