Subject Code: BC0048
Subject Name: Computer Networks
Credits: 4 Marks: 140
Part A (One mark questions)
1. The term “Computer Network” is used to mean an interconnected collection of--------------------
----
A) Mini computers
B) Super computers
C) Autonomous computers
D) Micro computers
2. A node, which is more powerful, and can handle local information processing or graphics
processing is called a------------------.
A) Workstation
B) Server
C) Network Operating System
D) Peer system
3. The collection of communication lines and routers is called --------------------
A) LAN
B) WAN
C) MAN
D) Communication subnet
4. Wireless networks are mainly classified into ------------- categories.
A) 4
B) 2
C) 3
D) 6
5. In OSI-ISO architecture -------------------- layer is concerned with transmitting raw bits over the
communication channel .
A) Data link Layer
B) Physical Layer
C) Session Layer
D) All of these
6. ------------------- is a set of rules governing the format and meaning of the packets, or
messages that are exchanged by the peer entities within a layer.
A) Interface
B) Reference model
C ) protocol
D) None of these
7. -------------- is needed in the physical layer , where all the traffic for all connections has to be
sent over at most a few physical circuits.
A) subnet
B) Multiplexing
C) decoding
D) encoding
8. In OSI/IOS model at which layer modulator/demodulators are used ?
A) data link layer
B) network layer
C) session layer
D) physical Layer
9. ------------------- is/ are caused by the random motion of the electrons in a wire and is
unavoidable.
A) Dispersion
B) Thermal noise
C) Delay distortion
D) all of these
10. ---------------- results from interference of different frequencies sharing the same medium.
A) Intermodulation
B) Cross talk
C) Impluse
D) Thermal noise
11. In which mode of transmission, transmitting and receiving clocks are independent of
each other.
A) Simplex
B) Half duplex
C) Synchronous
D) Asynchronous
12. UART stands for---------------------
A) user access remote terminal
B) universal asynchronous receiver transmitter
C) uni addressed remote terminal
D) none of these
13. The type of network topology in which all of the nodes of the network are connected to a
common transmission medium which has exactly two endpoints is called ------------------------------
A) Bus
B) Ring
C) Tree
D ) Mesh
14.--------------- combines characteristics of linear bus and star topologies.
A) Ring topology
B) A hybrid topology
C ) A tree topology
D) mesh topology
15. A key characteristic of ----------------------- networks is that resources within the network
are dedicated to a particular call.
A) message switching
B) Packet switching
C) Circuit switching
D) any of these
16. In a packet switching networks a typical upper bound on packet length is -------------.
A) 50 bytes
B) 100 bytes
C) 500 bytes
D) 1000 bytes
17. Which of these is an example for unguided transmission media?
A) coaxial cable
B) optical fibers
C) wireless
D) twisted pairs
18. The key concern in the design of transmission system is -------------- and ---------------
A) data rate ,distance
B) speed, accuracy
C) accuracy, simplicity
D) distance , cost
19. ------------- transmits a signal encoded beam of light by means of total internal reflection
A) co-axial cable
B) twisted pair
C) microwave
D) none of these
20. In a twisted pair cable, twisting reduces---------------.
A) noise
B) electrical interference
C) cross talk
D) all of these
21. Which layer transfers data between adjacent network nodes in a wide area network or
between nodes on the same local area network segment.
A) physical layer
B) Data link layer
C) Network layer
D) Session layer
22. The data link layer is split into -------------- and ----------------- sub layers.
A) MAC , LLC
B )MCC , LAC
C) MCM , LCM
D) CRC , MLC
23. To find the hamming distance between two words we perform --------------- operation
between those words.
A) NAND
B) NOR
C) EX-OR
D) OR
24. Given data is 1111101 , after using even parity the code becomes -------------------
A) 111111 1 1
B) 00000111
C) 10101010
D) 11111010
25. Pure ALOHA has a maximum throughput of -----------
A) 16.4 %
B) 18.4 %
C) 17.4 %
D) 1 %
26. preamble field of 802.3 frame is encoded using ------------------- encoding
A) Manchester
B) differential Manchester
C) Bi polar
D) uni polar
27. In the IEEE standards 802.5 standard is also called ------------------
A) Ethernet
B) Token Bus
C) Wireless local area network
D) Token Ring
28. What is the length of Ethernet address ?
A) 32 bits
B) 64 bits
C) 48 bits
D) 16 bits
29. How many levels of priority is defined in IPV4 protocol?
A) 4
B)2
C )8
D) 6
30. ----------------is a static algorithm in which every incoming packet is sent out on every
outgoing line except the one it arrives on.
A) Flooding
B) Congestion
C) Link state routing
D ) Distance vector
31. The main function of ------------------ layer is routing packets from the source machine to
the destination machine.
A) transport
B) physical
C) application
D) network
32. When hierarchical routing is used , the routers are divided into -------------
A) sectors
B ) regions
C) pages
D) segments
33. Which routing dominates the internet ?
A) Dynamic
B) static
C) synchronous
D) Asynchronous
34. Which of these layer is responsible for flow control ?
A) Network layer
B) Transport Layer
C) session layer
D) Application Layer
35. Which of these function belongs to transport layer ?
A) routing of packets
B) congestion control
C) email
D) none of these
36. TPDU is an acronym for ---------------------
A) Transport protocol data unit
B) trasferent product data unit
C) transitive product data unit
D) transfer protocol digital unit
37. Packet lifetime can be restricted to a known maximum by using this /these method.
A) Restricted subnet design
B) putting a hop counter in each packet
C) time stamping each packet
D) all of these
38. Which of these protocol guarantees reliable and in-order delivery of data from sender to
receiver. ?
A) TCP/IP
B) UDP
C)STP
D)TDP
39. Which of these is a feature of hubs ?
A) Hubs amplify the incoming signal.
B) Hubs understand frames, packets or headers
C) All lines coming into a Hub must operate at a same speed.
D) all of these
40. Hubs are classified as --------------- and --------------- hubs.
A) active, passive
B) synchronous, asynchronous
C) simplex, half duplex
D) one way , multi way
Part B (Two mark questions)
41. --------------- have a single communication channel that is shared by all the users on the
network.
A) Point-to-poit
B) Broadcast networks
C) Protocol
D) PAN
42. The world wide Internet is a well known example of ------------------.
A ) PAN
B) Subnet
C) Intra-Network
D) inter-network
43. Which Layer is Responsible for Congestion Control ?
A) Network Layer
B) Datalink Layer
C) Transport Layer
D) Application layer
44) -------------Modulation, is a technique of conversion between the representation of digital data
in user equipment and the corresponding signals transmitted over a communications channel.
A) Line coding
B) Demodulation
C) Modulation
D) Segmentation
45. Videoconferencing is an example for ------------------- communication
A) Simplex
B) Half duplex
C) Full duplex
D) serial
46. E-mail is an example of -------------- mode of communication where one party can send a
note to another person and the recipient need not be online to receive the e-mail.
A) asynchronous
B) synchronous
C) full duplex
D) either A) or B)
47. Following are the advantages of tree topology
i)Point-to-point wiring for individual segments.
ii)Supported by several hardware and software venders.
iii) Easy to install and wire
A) i) only
B) i) and ii) only
C) iii) only
D) i) ,ii) and iii)
48. The most well-Known use of -------------------- is internet
A) Packet switching
B) circuit switching
C) message switching
D) multiplexing
49. Transmission medias are classified into two main categories, which are -------------- and ------
--------------.
A) twisted pair, coaxial
B) guided , unguided
C) analog, digital
D) synchronous, Asynchronous
50. Which of the following transmission media suffers more from transmission impairment.
A) coaxial cable
B) Optical fiber
C) twisted pair
D) wave guides
51. The DLL translates the physical layer's raw bit stream into discrete units called ---------------
A) packets
B) messages
C) frames.
D) TPDU
52. The Hamming Distance for the codes generated using either even or odd parity will be-------
-----------
A) 2
B) 4
C)1
D) 0
53. Who defined ALOHA protocol ?
A) Claude shanon
B) Nyquist
C) Abramson
D) Newton
54. What is the pattern of a preamble ?
A) 11110000
B) 11111111
C) 00000000
D) none of these
55. Which of these is/are the properties of routing algorithm ?
A) correctness
B) simplicity
C) stability
D) all of these
56. Where are routing tables placed ?
A) in network interface card
B) in routers memory
C) in server memory
D) in a subnet’s memory
57. Which of these is a minimal message-oriented transport layer protocol.
A) UDP
B) SMTP
C)HTTP
D)TCP/IP
58. Two main important protocols of transport layer are ----------- and -------------.
A) SMTP, HTTP
B) TCP, UDP
C) UDP, HTTP
D) SMTP, UDP
59. --------------- are fast multi-port bridges that provide an economical way to resolve network
congestion.
A) Switches
B) Gateways
C) Routers
D) Brouters
60 In ----------------------- configuration, the switch begins to forward the packet as soon as it
is received. No error checking is performed on the packet, so the packet is moved
through very quickly.
A) cut-free
B) franment-free
C ) store-and-forward
D) cut-through
Part C (Four mark questions)
61. Computer networks may be classified according to the -------------- at which they operate
according to some basic reference models that are considered to be standards in the industry
such as the----------- OSI reference model and the -----------TCP/IP model.
A) network layer, seven layer, four layers
B) transport layer, five layer, six layer
C) Physical layer, five layer, four layer
D) Physical layer, four layer, four layer
62. Match the following.
1. Physical Layer i) Dialogues control
Network Layer ii) Raw bits
Session Layer iii) Data encryption
Presentation Layer iv) Routing Packet
A) 1-iii, 2-iv, 3- ii ,4-i
. 1-ii, 2-iv, 3-i , 4-iii
/ 1-iii, 2-ii,3-iv,4-i
5 1-iv,2-iii,3-i,4-ii
63. What are the advantages of synchronous communication.
1. it reduces overhead bits
2. The character is self contained & Transmitter and receiver need not be synchronized
3. It overcomes the two main deficiencies of the asynchronous method, that of inefficiency
and lack of error detection.
4. Transmitting and receiving clocks are independent of each other
A) 1,2, and 3
B) 1 and 3
C) 1,2 and 4
D) 1,2,3 and 4
64. Match the following
1) FDM i)Light streaming
2) TDM ii) internet
3) WDM iii) analog communication
4) Packet switching Iv) digital communication
A) 1-iv, 2- i, 3-ii, 4- iii
B) 1- iii, 2-iv , 3-i, 4-ii
C) 1-ii, 2-i,3-iv 4-iii
D) 1-iii, 2-i, 3-ii, 4-iv
65. Match the following
1. CAT3 cable i) high speed computer communication
2. CAT5 cable ii)2 GHz t0 40 GHz
3. CAT6 & CAT 7 cable iii) 16 to 100 MHz
4. wireless transmission iv) 250 MHz to 600 MHz
A) 1-iii, 2-I 3-iv, 4-ii
B) 1-iii, 2-iv 3-ii 4-i
C) 1-ii, 2-iii, 3-iv 4-i
D) 1-iv 2-iii, 3-i 4-ii
66. State true or false
i) The Hamming Distance for the codes generated using either even or odd parity will
be 2.
ii) The DLL translates the physical layers raw bit stream into discrete units called
packets
iii) The network layer wants messages to be delivered to the remote peer in the exact
same order as they are sent.
iv) The data link layer is split into MAC and LLC sub layers.
A) true, true, true true
B) true, false , true, false
C) true, false, true, true
D) true, true, false, false
67. Match the following
1. preamble i. error checking
2. SOF ii. 10101010
3. checksum iii. 2 byte
4. Length iv 1 byte
A) 1- iv 2-i 3-ii 4-iii
B) 1- ii 2-iii 3-iv 4-i
C) 1-iii 2-iv 3-ii 4-i
D) 1-ii 2-iv 3-i 4- iii
68. State true or false
i) Low bandwidth lines cause congestion
ii) Slow processors cause congestion.
iii) Adding more memory increase congestion
A) true, true, false
B) false ,true, false
C) true, false , false
D) true , true, true
69. State true or false
1. TCP protocol is a connection less protocol.
2. Automatic repeat request schemes may be used to retransmit lost or corrupted data.
3. Automatic repeat request may keep the network in a congested state.
4. TPDU is an acronym for transfer product data unit.
A) true true true true
B) False true false false
C) false true true false
D) true false false true
70. State true or false
i. The connection establishment protocol introduced by Tomlinson is known as a three way
handshake.
ii. Asymmetric release is the way the telephone system works.
iii. The 16-bit checksum field is used for error-checking of the header and data.
A) false, false, false
B) true, true, true
C) true, false, false
D) false, false, true
71. Match the following
1. Network layer i. HUB
2. Data link layer ii. Gateway
3. Transport layer iii. Router
4. Physical layer iv. Switch
A) 1-iii 2-i 3- iv 4-ii
B) 1-iii 2-iv 3-ii 4-I
C) 1-ii 2-iii 3-iv 4-i
D) 1-iv 2-i 3-ii 4- iii
72. State true or false
i. Both hubs and switches come in managed and unmanaged versions.
ii. A bridge unlike repeaters will not start retransmission until it has received the
complete packet.
iii. The looping problem cannot be avoided by using the Spanning Tree Algorithm
(STA).
A) true, true, true
B) false, true, false
C) true, true, false
D) false, false, false
73. Match the following
1. shortest path algorithm i. forwarding
2. distance vector routing ii. Session routing
3. virtual circuit iii. Static routing
4. Datagram iv. Dynamic routing
A) 1-iii, 2- iv, 3-ii, 4-i
B) 1-ii ,2-iii , 3-iv , 4-i
C) 1-iii, 4-ii, 3-i, 4- iv
D) 1-iv , 2-iii, 3-ii, 4-i
74. state true or false
1. CSMA/CD is a layer 2 protocol in a layer 2 protocol in the OSI model.
2. Network interface cards (NICs) or chips normally do not accept packets addressed to other
Ethernet stations.
3. P- persistent CSMA is a slotted approximation.
4. generally LANs can sense the channel but wireless networks cannot sense the channel
effectively.
A) true, false, true, false
B) false, false, false, true
C) true, true , true , true
D) true, true, false, false
75. Find the transmitted code if the frame is (MSB) 1101011011 (LSB) and generator
4
polynomial is x
+ x + 1.
A) 1101011011 1110
B) 1001011011 0010
C) 1000011011 1100
D) 1111011000 1110
Answer Keys
Part - A Part - B Part - C
Q. No. Ans. Key Q. No. Ans. Key Q. No. Ans. Key Q. No. Ans. Key
1 C 21 B 41 B 61 A
2 A 22 A 42 D 62 B
3 D 23 C 43 A 63 B
4 C 24 D 44 C 64 B
5 B 25 B 45 C 65 A
6 C 26 A 46 A 66 C
7 B 27 D 47 B 67 D
8 D 28 C 48 A 68 D
9 B 29 C 49 B 69 C
10 A 30 A 50 C 70 B
11 D 31 D 51 C 71 B
12 B 32 B 52 A 72 C
13 A 33 A 53 C 73 A
14 C 34 B 54 D 74 C
15 C 35 D 55 D 75 A
16 D 36 A 56 B
17 C 37 D 57 A
18 A 38 A 58 B
19 D 39 C 59 A
20 B 40 A 60 D
