Computer Network Test - 3 - PDF Flipbook

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GATE
CSE

Computer
Network

Test-03Solutions

COMPUTER NETWOK
1. Consider a 50-kbps satellite channel with 500 milliseconds

round trip propagation delay. If the sender wants to transmit
1000-bit frames, how much time will it take for the receiver to
receive the frame?
a) 250 milliseconds
b) 20 milliseconds
c) 520 milliseconds
d) 270 milliseconds
Answer: (d)
Solution:
Total time = Transmission time of Message + propagation time
Round trip tie = 2 × propagation time
So, propagation time = 500/2 = 250 ms
Transmission time = frame size/ bandwidth
= 1000 bits/ 50 kbps = 20 ms
Total time to receive the frame by the receiver
250+ 20 = 270 ms
2. What is compression ratio in a typical mp3 audio file?
a) 4:1
b) 6:1
c) 8:1
d) 10:1
Answer: (d)

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Solution:
101 is the compression ratio in typical mp3 audio file.
3. Frequency shift keying is used mostly in
a) Radio transmission
b) Telegraphy
c) Tele phone
d) None of the above
Answer: (b)
Solution:
Frequency shift keying is used mostly in telegraphy FSK is a
frequency modulation schema in which digital information is
transmitted though discrete frequently changed of a carrier
signal
4. We cannot delete the ___icon but we can make it invisible.
a) Recycle
b) My computer
c) internet explorer
d) None of these
Answer: (a)
Solution:
We cannot delete the recycle icon but we can made it invisible
5. Which one is a collection of templates and rules?
a) XML
b) CSS
c) DHTML

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d) XSL

Answer: (d)

Solution:

XSL is a language for expressing style sheets an XSL style

sheet is like with CSS a file that describes how to display an

XML documents of a given type XSL shares the functionality

and is compatible with CSS2 (although it uses a different

syntax) it also adds: A transformation language for XML

document: XSLT

6. Determine the maximum length of the cable (in km) for

transmitting data at a rate of 500 Mbps in an Ethernet LAN with

frames of size 10,000 bits. Assume the signal speed in the cable

to be 2, 00,000 km/s.

a) 1

b) 2

c) 2.5

d) 5

Answer: (b)

Solution:

L = 10, 000 bits and B = 500 ×106 bps

V = 2 ×


d = ×
2×

d = 10,000×2×108 = 2000m
2×500×106

d = 2 km

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7. Consider the following two statements:
(i) A Hash function, which is used for computing digital
signatures, is an injective function
(ii) An encryption techniques such as DES performs a
permutation on the elements of its input alphabet

Which of the following options is valid for the above two
statements?
a) Both are false
b) Statement (i) is true and the other is false
c) Statement (ii) is true and the other is false
d) Both are true
Answer: (d)
Solution:
→Hash function is one to one function for each message x, the
hash value y = H(x) is unique.
→DES performs Initial permutation on all the input characters.
8. The PROJECT Command will create new table that has
a) more fields than the original table
b) more rows than original table
c) both (a) and (b)
d) none of these
Answer: (d)
Solution:
Projection means choosing which columns the query shall
return, and selection means which rows are to be returned

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9. An example of a file extension is;
a) text
b) Pict
c) mp3
d) web
Answer: (b)
Solution:
MP3 is an example of file extension

10. if an integer needs two bytes of storage, then the maximum
values of a signed integer is
a) 216-1
b) 215-1
c) 216
d) 215
Answer: (b)
Solution:
In two bytes there are total 16 bits for signed integer one bit
(MSB) is reserved for representing sign ( 1 for negative, and 0
for positive numbers) Now remaining 15 bits representing
magnitude from 0 to (215 -1) for positive and same for negative
numbers

11. X.25 is____Network.
a) Connection Oriented Network
b) Connection Less Network
c) Either Connection Oriented or Connection Less

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d) Neither Connection Oriented nor Connection Less
Answer: (a)
Solution:
X.25 is an ITU-T standard protocol suite for packet switching
wide Area network (WAN) communication
NASP addressing facility was added in this enabled x.25 to
better meet the requirements of OSI connection oriented
Network service (CONS)
12. A digital signalling technique is required to operate at 4800 bps
(bits per second). Each signal element encodes 8-bit bytes using
multilevel phase shift keying. In order to find the minimum
bandwidth required, the most appropriate formula to use would
be
a) Signal-to-Quantization ratio for the encoding scheme
b) Nyquist's formula for maximum channel capacity
c) Shannon's law for maximum capacity on a noisy channel
d) None of these
Answer: (d)
13. The below figure represents which one of the following UML
diagram for a single send session of an online chat system,

a) Package Diagram
b) Activity Diagram
c) Class Diagram
d) Sequence Diagram

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Answer: (b)
Solution:
The above figure represents an activity diagram. An activity
diagram is a flow chart to represent the flow from one activity to
another activity.
14. This flow can be sequential, branched or concurrent. What
frequency range is used for micro-wave communications,
satellite and radar?
a) Low frequency: 30 kHz to 300 kHz
b) Medium frequency: 300 kHz to 3 MHz
c) Super high frequency: 3000MHzto 30000MHz
d) Extremely high frequency: 30,000 MHz
Answer: (d)
15. Synchronous protocols
a) transmit characters one at a time
b) allow faster transmission than asynchronous protocols do
c) are generally used by personal computers
d) all of these
Answer: (b)
16. In Ethernet, the source address field in the MAC frame is the
_____address.
a) original sender's Physical
b) Previous station's Physical
c) next destination's Physical
d) original sender's service Port

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Answer: (b)
Solution:
In Ethernet, the source address field in the MAC frame is the
previous stations physical address. Source and destination’s
physical address changes multiple time throughout the route
may times, whereas the logical address i.e., the IP address never
change throughout the path from the original search to the final
receiver.
17. The cost of the network is usually determined by
a) time complexity
b) switching complexity
c) circuit complexity
d) none of these
Answer: (b)
Solution:
Circuit complexity is a branch of computational complexity
theory in which Boolean functions are classified according to
the size or depth of Boolean circuits that compute them the
circuit size complexity of a Boolean function is the minimal
size of any circuit computing.
18. A network which is used for sharing data, software hardware
among several users owning microcomputers is called
a) WAN
b) MAN
c) LAN

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d) VAN
Answer: (c)
19. The best-known example of a MAN is:
a) Ethernet
b) Cable Television
c) FDDI
d) |EEE 802 3
Answer: (b)
Solution:
A metropolitical area network(MAN) is a computer network that
inconnects users with computer resources in a geographic area
or region larger than that covered by even a large local area
network (LAN) but smaller that the area covered by wide area
network (WAN)
Rthernet is afamily of com[puter networking thechnologies
commanly used in local area networks (LANS) and
metropolitian area networks (MANs) IEEE 802.3 is aworking
group using wired etherenet
20. The simultaneous transmission of data to a number of stations is
called
a) broadcast
b) bandwidth
c) aloha
d) analog transmission
Answer: (a)

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21. Which of the following is an unsupervised neural network
a) RBS
b) Hopfield
c) Back propagation
d) Kohonen
Answer: (d)
Solution:
Kohonen is an unsupervised neural network. Remaining all the
three RBS, Hopfield, back propagation is supervised neural
networks. Kohonen is a self-organizing map which is a type of
artificial neural network that is trained under unsupervised mode
of learning to produce a low-dimensional discretized
representation of the input space of the training samples, called
a map.

22. The address resolution protocol (ARP) is used for
a) Finding the IP address from the DNS
b) Finding the IP address of the default gateway
c) Finding the IP address that corresponds to a MAC address
d) Finding the MAC address that corresponds to an IP address
Answer: (b)
Solution:
UTP stands for unshielded twisted pair which is made up by
twisting two unshielded wires on each other.

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23. What does the URL need to access documents?
i. Path name
ii. Host name
iii. DNS
iv. Retrieval method
v. Server port number
a) i, ii and iii
b) i, iii and v
c) i, ii and iv
d) iii, iv and v
Answer: (b)
Solution:
URL is an acronym for uniform resource locator and is a
referred (an address) to a resource on the internet A. URL has
two main components
Protocol identifier for the URL http:// example.com, the
protocol identifier is URL http:// example.com, the resource
name is example.com
When a user access a distributed internet service using a URL,
the domain name (DNS) of the URL is translated to the IP
address of a server that is proximal to the user
Port number of http is 80

24. What is the meaning of � � � � signal in Intel 8151A?
a) Read (when it is low)
b) Read (when it is high)

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c) Write (when it is low)
d) Read and Write (when it is high)
Answer: (a)
Solution:
� � � � Signal in Intel 8151A means read, when it is low.
25. How does Packet Burst affect network performance?
a) It increases speed at which packets are distributed.
b) It increases network bandwidth.
c) It helps in error control.
d) It helps in secure communication.
Answer: (b)
26. On a LAN, where are IP datagrams transported?
a) ln the LAN header
b) ln the application field
c) ln the information field of the LAN frame
d) After the TCP header
Answer: (c)
Solution:
On a LAN, the IP datagrams are transported in the information
27. Field of Ethernet frame To avoid transmission errors, a check
figure is calculated by
a) transmitting computer
b) receiving computer
c) a personal computer
d) all of these

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Answer: (c)
28. What is the transmission signal coding method for a T1 carrier

called?
a) Binary
b) NRZ
c) Bipolar
d) Manchester
Answer: (c)
Solution:
In tele-communication, bipolar encoding is a type of return to
zero line code, where two non-zero values are used, so that the
three values are +, -, and zero
29. Which of the following is widely used inside the telephone
system for long-haul data traffic?
a) ISDN
b) ATM
c) Frame Relay
d) STN
Answer: (b)
Solution:
ATM a core protocol used over the Sonet/SDH backbone of the
public switched telephone network and ISDN.

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30. Carrier is
a) One or more conductors that serve as a common connection
for a related group of devices
b) a continuous frequency capable of being modulated or
impressed with a second signal
c) the condition when two or more sections attempt to use the
same channel at the same time
d) a collection of interconnected functional units that provides a
data communications service among stations attached to the
network
Answer: (b)

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