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MCQs on Computer Networks - Practice Paper for BSNL TTA Exam

1. Which layer is immediately below the data link layer?
a. Physical
b. Network
c. Transport
d. Application
Answer: A
2. What does flow control determine?
a. When a device can transmit
b. Whether a device is connection oriented or connectionless
c. Both a and b
d. Neither a nor b
Answer: C

3. Converting data into signals by transforming and encoding the information to produce electromagnetic signals is the functionality of a ___________.
a. Source
b. Transmitter
c. Receiver
d. Destination
Answer: B
4. Which of the following describes stop-and-wait flow control?
a. It is simple
b. It is complex
c. It is best with small frames
d. It is best over long distances
Answer: A
5. What must a sender do before a receiver’s sliding windows buffer can expand?
a. Send an acknowledgment
b. Receive an acknowledgment
c. Either a or b
d. Neither a nor b
Answer: A
6. Controlled access line discipline is used with which type of circuit?
a. Point-to-point
b. Multipoint
c. Either a or b
d. Neither a nor b
Answer: B
7. Which of the following is the simplest error-detection method?
a. Parity
b. Longitudinal redundancy checking
c. Checksum checking
d. Cyclic redundancy checking
Answer: A
8. Which type of error detection uses binary division?
a. Parity
b. Longitudinal redundancy checking
c. Checksum checking
d. Cyclic redundancy checking
Answer: D
9. Which of the following is also called forward error correction?
a. Simplex
b. Retransmission
c. Detection-error coding
d. Error-correction coding
Answer: D
10. The solution to the problem of scalability of the Internet is to break the network down into manageable parts, or domains each called ____________.
a. Router
b. Autonomous system
c. Interface
d. Bridge
Answer: B
11. For a CSMA/CD network, twice the propagation time between the two most distant stations is called _________________.
a. Slot time
b. Transfer time
c. Round trip delay time
d. Both a and c
Answer: D
12. When a network interface has a failure in its circuitry, it sends a continuous stream of frames causing the Ethernet LAN to enter a Collapse state. This condition is known as __________.
a. Scattering
b. Blocking
c. Jabbering
d. Refreshing
Answer: C
13. The IEEE 802.3 specification divides the data link layer into two sub-layers: the Logical link control sub-layer and the medium access control sub-layer. An example of one implementation of medium access control is _______________.
a. TCP protocol
b. CSMA/CD protocol
c. IP protocol
d. UDP protocol
Answer: B
14. In an object-oriented model, when different classes have operations with the same name but different implementation, they are having the property of ___________.
a. Inheritance
b. Association
c. Polymorphism
d. Aggregation
Answer: C
15. Telnet, FTP, SMTP, DNS, HTTP are examples of protocols that are used in ____________________.
a. Application layer of OSI reference model
b. Presentation layer of OSI reference model
c. Session layer of OSI reference model
d. Data link layer of OSI reference model
Answer: A
16. Session control, file and printer are three categories of messages which pass requests and acknowledgements in a client-server platform. They are used by __________________.
a. TCP/IP protocol
b. Ethernet protocol
c. CSMA/CD protocol
d. SMB protocol
Answer: D
17. ____________________ is a technique which transforms an analogue telephone circuit into a digital signal, and involves three consecutive processes: sampling, quantization and encoding.
a. Frequency Modulation (FM)
b. Pulse Code Modulation (PCM)
c. Amplitude Modulation (AM)
d. Phase Modulation (PM)
Answer: B
18. The frame alignment word is a sequence of bits that allows the start of each STM-1 frame to be clearly identified within SDH network. It is contained within _________________.
a. Regenerator section overhead
b. Multiplex section overhead
c. Synchronous section overhead
d. Sequence section overhead
Answer: A
19. The Star arrangement in the figure below shows how it is used to distribute the timing source within a telecommunication station in SDH network.
This is an example of ___________________.
a. Intra-station synchronization
b. Inter-station synchronization
c. Ultra-station synchronization
d. Multi-station synchronization
Answer: A
20. ____________ is the standard defined by the American National Standard Authority, ANSI T1 for synchronous operation used in North America.
a. DXC
b. STM-1
c. ADM
Answer: D
21. The failure density function, f(t) is used to give the probability of failure during an interval of time. It is known as ______________.
a. Probability density distribution
b. Cumulative probability distribution
c. Cumulative density distribution
d. Failure probability distribution
Answer: A
22. _______________ is one of the Telecommunication management network (TMN) functional blocks that will convert TMN information into a format that can be easily understood by the user.
a. Operations system function block
b. Workstation function block
c. Reference function block
d. Network element function block
Answer: B
23. In Telecommunication management Network (TMN) system, the role of the manager is to issue commands and requests to the agent. These commands and requests are known as ________________.
a. Notifications
b. Feedbacks
c. Operations
d. Acknowledgements
Answer: C
24. The sequence of the binary digits representing the outcomes of parity checks in Hamming codes is known as _________________.
a. Look-up entry
b. Hamming distance
c. Radix
d. Syndrome
Answer: D
25. Rather than sending the absolute value of each sample, it is possible to achieve a smaller transmission bit-rate by sending the difference between consecutive samples. This is known as _______________.
a. Delta modulation
b. Delta–sigma modulation
c. Adaptive delta modulation
d. Differential PCM
Answer: A
26. The electron beam in the cathode ray tube (CRT) inside the TV set is made to scan the whole visible surface of the screen in a zigzag pattern. This is known as ____________.
a. Raster
b. Picture line
c. Frame
d. Broadcast
Answer: A
27. The figure below shows an example of a modulation system used in digital communication.
What is that modulation system?
a. PCM Modulation.
b. Delta Modulation.
c. Sigma Modulation.
d. Differential Modulation.
Answer: B
28. One of the compression techniques in communication uses the fact that in most pictures, there is considerable correlation between neighboring areas that is a high degree of redundancy in the data to compress. This type of compression is known as _____________.
a. Temporal compression
b. Dynamic compression
c. Spatial compression
d. Random compression
Answer: C
29. Reversible or lossless coding is a type of coding for which the exact data can be recovered after decoding. This type of coding is used by _________________.
a. PCM encoding
b. Huffman encoding
c. Run-length encoding
d. Both b and c
Answer: D
30. The error represented by the difference between the original and quantized signals set a fundamental limitation to the performance of PCM systems known as __________________.
a. Dynamic range
b. Quantization noise
c. Detection-error
d. Correction-error
Answer: B

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