PU CET Lahore (Engineering & CS) computer science Data Communication — Set 2

PU CET Lahore (Engineering & CS) computer science Data Communication — Set 2

1. Question 1

   Q1. Which protocol is used for error detection and correction in data communication?

   • A) TCP
   • B) UDP
   • C) HDLC
   • D) CRC

   Answer: CRC

   Explanation: CRC (Cyclic Redundancy Check) is a protocol used for error detection and correction by calculating a checksum.

2. Question 2

   Q2. What is the data transmission rate measured in?

   • A) Bytes per second
   • B) Bits per second
   • C) Packets per second
   • D) Frames per second

   Answer: Bits per second

   Explanation: Data transmission rate is measured in bits per second (bps), representing the number of bits transmitted over a channel.

3. Question 3

   Q3. In a full-duplex communication, data can be transmitted

   • A) In one direction at a time
   • B) In both directions simultaneously
   • C) In one direction only
   • D) None of the above

   Answer: In both directions simultaneously

   Explanation: Full-duplex communication allows data transmission in both directions simultaneously, enabling simultaneous sending and receiving.

4. Question 4

   Q4. Which of the following is a characteristic of a simplex communication channel?

   • A) Data can be transmitted in both directions
   • B) Data can be transmitted in one direction only
   • C) Data transmission is not possible
   • D) Data can be transmitted in both directions simultaneously

   Answer: Data can be transmitted in one direction only

   Explanation: A simplex channel allows data transmission in one direction only, from transmitter to receiver.

5. Question 5

   Q5. What is the purpose of the stop-and-wait protocol?

   • A) To ensure reliable data transfer
   • B) To improve network throughput
   • C) To reduce packet loss
   • D) To increase network congestion

   Answer: To ensure reliable data transfer

   Explanation: The stop-and-wait protocol ensures reliable data transfer by waiting for an acknowledgment before sending the next packet.

6. Question 6

   Q6. What is the function of the MAC (Media Access Control) sublayer?

   • A) To manage the physical transmission medium
   • B) To control access to the transmission medium
   • C) To provide error detection and correction
   • D) To manage network routing

   Answer: To control access to the transmission medium

   Explanation: The MAC sublayer controls access to the transmission medium, resolving contention between devices.

7. Question 7

   Q7. Which type of cable is immune to electromagnetic interference (EMI)?

   • A) Coaxial cable
   • B) Twisted pair cable
   • C) Fiber optic cable
   • D) Shielded twisted pair cable

   Answer: Fiber optic cable

   Explanation: Fiber optic cables are immune to EMI as they transmit data as light signals through glass or plastic fibers.

8. Question 8

   Q8. What is the primary function of a router?

   • A) To connect multiple networks together
   • B) To amplify weak signals
   • C) To filter out unwanted traffic
   • D) To provide network security

   Answer: To connect multiple networks together

   Explanation: A router connects multiple networks together, routing traffic between them based on network addresses.

9. Question 9

   Q9. In a TCP/IP network, what is the purpose of the ARP protocol?

   • A) To resolve IP addresses to MAC addresses
   • B) To resolve MAC addresses to IP addresses
   • C) To provide network routing
   • D) To manage network congestion

   Answer: To resolve IP addresses to MAC addresses

   Explanation: ARP resolves IP addresses to MAC addresses, enabling devices to communicate at the data link layer.

10. Question 10

    Q10. What is the maximum data rate of a T1 line?

    • A) 1.544 Mbps
    • B) 2.048 Mbps
    • C) 10 Mbps
    • D) 100 Mbps

    Answer: 1.544 Mbps

    Explanation: A T1 line has a maximum data rate of 1.544 Mbps, a standard for digital transmission in North America.

11. Question 11

    Q11. Which protocol is used for sending email?

    • A) SMTP
    • B) HTTP
    • C) FTP
    • D) SNMP

    Answer: SMTP

    Explanation: SMTP (Simple Mail Transfer Protocol) is used for sending email between mail servers and clients.

12. Question 12

    Q12. What is the primary function of the transport layer?

    • A) To provide reliable data transfer
    • B) To manage network routing
    • C) To control access to the transmission medium
    • D) To provide network security

    Answer: To provide reliable data transfer

    Explanation: The transport layer provides reliable data transfer, ensuring that data is delivered error-free and in the correct order.

13. Question 13

    Q13. In a packet-switched network, what is a packet?

    • A) A fixed-size block of data
    • B) A variable-size block of data
    • C) A frame with error detection
    • D) A segment with flow control

    Answer: A variable-size block of data

    Explanation: In packet switching, a packet is a variable-size block of data with a header containing control information.

14. Question 14

    Q14. What is the purpose of the TTL (Time To Live) field in an IP packet?

    • A) To prevent packet looping
    • B) To ensure packet delivery
    • C) To manage network congestion
    • D) To provide network security

    Answer: To prevent packet looping

    Explanation: The TTL field prevents packet looping by limiting the number of hops a packet can take.

15. Question 15

    Q15. Which device operates at the physical layer of the OSI model?

    • A) Router
    • B) Switch
    • C) Repeater
    • D) Bridge

    Answer: Repeater

    Explanation: A repeater operates at the physical layer, amplifying weak signals to extend the transmission distance.

16. Question 16

    Q16. What is the primary function of the data link layer?

    • A) To provide reliable data transfer
    • B) To manage network routing
    • C) To control access to the transmission medium
    • D) To provide error detection and correction

    Answer: To control access to the transmission medium

    Explanation: The data link layer controls access to the transmission medium and provides error detection and correction.

17. Question 17

    Q17. Which of the following is a type of network topology?

    • A) Star
    • B) Mesh
    • C) Bus
    • D) All of the above

    Answer: All of the above

    Explanation: Star, mesh, and bus are all types of network topologies, each with its own advantages and disadvantages.

18. Question 18

    Q18. In a CSMA/CD network, what is the minimum frame size required?

    • A) 32 bytes
    • B) 64 bytes
    • C) 128 bytes
    • D) 256 bytes

    Answer: 64 bytes

    Explanation: The minimum frame size is 64 bytes to ensure collision detection, as per Ethernet standards.

19. Question 19

    Q19. How many bits are used for the IP address in IPv4?

    • A) 16
    • B) 32
    • C) 64
    • D) 128

    Answer: 32

    Explanation: IPv4 addresses are 32 bits long, typically represented in dotted decimal notation.

20. Question 20

    Q20. What is the primary purpose of subnetting?

    • A) Improving security
    • B) Reducing broadcast traffic
    • C) Increasing address space
    • D) Simplifying routing

    Answer: Reducing broadcast traffic

    Explanation: Subnetting reduces broadcast traffic by dividing a large network into smaller, manageable sub-networks.