Networking Exam Sample Question

Networks and Networking

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SECTION A Answer ALL questions in this section. This section consists of 20 questions and carries a total of 40 marks. 1. Which of the following IEEE specifications refers to the CSMA/CD access method? a) b) c) d)

802.5 802.6 802.3 802.4

2. Which of the following sentences concerning Synchronous transmission is TRUE? a) b) c) d)

This approach is best suited for transmitting larger streams of information. Both the sender and receiver devices do not need to be synchronized. Information is sent in forms of separate bytes. There are gaps between each byte sent.

3. What is one (1) purpose performed by the monitor station for a Token ring network? a) It is responsible for regulating the traffic over the ring network. b) It is responsible for assigning network addresses for the devices on the ring network. c) It prevents any collision of data frames on the ring network. d) It prevents data frames from circulating the ring network endlessly. 4. Which of the following IP addresses belongs to the class C classification? a) b) c) d)

191.165.16.10 223.132.10.8 226.204.13.80 128.60.30.14

5. Which of the following problems is NOT experienced by Token ring and FDDI networks? a) Access delay b) Data packets collision c) Ring delay d) Token availability 6. Which of the following statements correctly describe an advantage of frame relay over X.25? Diploma Part 2

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200801

Networks and Networking

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a) It provides peer-to-peer connection for the nodes connected to the WAN. b) It provides a consistent data rate for the user whether or not the bandwidth is used up. c) It allows for variable length packets, which reduces the delay over the network. d) It allows checking of errors only at the destination router. 7. Which of the following scenarios is NOT a over IP (VoIP) technology? a) b) c) d)

benefit of implementing Voice

Zero cost of implementation. Multi-vendor interoperability. Increase in productivity. Reduction in communication costs.

8. Which of the following Open Systems Interconnection (OSI) layers does the hub operate on? a) b) c) d)

Physical. Data link. Network. Transport.

9. Which of the following IP address classes creates equal number of network id and host id addresses? a) b) c) d)

Class B Class D Class A Class C

10. Using the Cyclic Redundancy Check (CRC) technique; with the data unit of 111111, the divisor 1010, and the remainder 110, which of the following values is the dividend at the receiver? a) b) c) d)

111111011 111111010 111111110 101010110

Diploma Part 2

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200801

Networks and Networking

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11. Which of the following pairs of answers is most appropriate for the statement; ‘10Base2 uses __________ cable, while 10Base5 uses __________’? a) b) c) d)

thin coaxial, thick coaxial twisted-pair, thick coaxial thick coaxial, thin coaxial fibre-optic, thin coaxial

12. Which of the following ISDN channels is used for applications requiring a transmission rate greater than 64kbps? a) b) c) d)

B C D H

13. What is the sampling rate for an analog signal with different frequencies which are 1.2KHz, 3KHz and 20Hz. Calculate the sampling rate using Nyquist Theorem. a) b) c) d)

6000 samples per second. 1500 samples per second. 400 samples per second. 240 samples per second.

14. In a ______________ transmission mode, transmission can occur both ways between sender and receiver but only one person can transmit at one time. a) b) c) d)

full duplex simplex half duplex dual duplex

15. The ___________________ is a type of wave propagation method which takes place closest to the earth and can spreads in all directions including underwater. a) b) c) d)

line of sight propagation surface propagation tropospheric propagation ionospheric propagation

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200801

Networks and Networking

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16. _______________ is one of the modulation techniques in digitization process which takes constant samples of the analog waves and charts it. a) b) c) d)

Quadrative Amplitude (QAM) Pulse Code Modulation (PCM) Amplitude Modulation (AM) Pulse Amplitude Modulation (PAM)

17. Which of the following statement is TRUE regarding circuit switching? a) Circuit switched networks are designed for digital telephone communication. b) The link would be established only if there is a transmission which needs to be done at the current time. c) Circuit-switching is very well suited for data signals, whose inherent nature of transmission is burst. d) Once a circuit has been established, it would remain so for the duration of the transmission. 18. Which of the following statements concerning a typical router is FALSE? a) It functions up to layer 3 of the OSI model. b) It is capable of determining which of its available connections would be best to relay a data packet. c) It is not able to connect networks using different topologies together. d) It will scan the addresses of the incoming packet against those stored in the routing table. 19. ______________ technique could facilitate bandwidth on demand because when an input channel requires a higher data rate, it would be demuxed into multiple paths and multiplexed at the destination. a) b) c) d)

Frequency Division Multiplexing Synchronous Time Division Multiplexing Asynchronous Time Division Multiplexing Inverse Multiplexing

20. Based on the diagram below, the stream of bits received at the destination is not the same as the bit which are originally sent from the sender. It shows that error had Diploma Part 2

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Networks and Networking

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occurs during the transmission. Which of the following best describes that particular type of error?

a) This multiple bit error occurs when two or more bits have been altered during the transmission. b) The best way to detect this type of error is using the vertical redundancy check (VRC) where a single parity bit will be appended to the stream of bits. c) This type of error can only be detected using Cyclic Redundancy Check (CRC) technique. d) This type of error is called burst error.

Diploma Part 2

Asia Pacific Institute of Information Technology

200801

Networks and Networking

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SECTION B Answer any FOUR questions in this section. This section consists of 5 questions and each carries 15 marks. This section carries a total of 60 marks. QUESTION B1. a) Identify the two types of antenna used in terrestrial microwave and briefly explain how does microwave signal propagates. (4 marks) b) Describe how crosstalk occurs and explain how does shielded twisted pair (STP) cables can overcome crosstalk. (3 marks) c) What is FDDI stands for and briefly explain why FDDI is more suitable for data network compared to token ring implementation. (5 marks) d) List the three (3) modulation techniques for analog to analog conversion. (3 marks) (Total marks: 15 marks) QUESTION B2. a) What is multiplexing? Briefly explain any two (2) benefits of multiplexing. (5 marks) b) What is the difference between serial transmission and parallel transmission? (2 marks) c) Briefly explain any three (3) considerations for implementing VoIP in a company’s network. (3 marks) d) Explain the meaning of “CSMA/CD” and what purpose it serves. (5 marks) (Total marks: 15 marks) Diploma Part 2

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Networks and Networking

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QUESTION B3. a) Assume seven (7) devices are arranged in a mesh topology. How many cables are needed to fully connect each device together? Show the working to the answer. (2 marks) b) Discuss and explain the advantages and disadvantages of star topology. (4 marks) c) Briefly explain the characteristic of packet switching using datagram approach and virtual circuit approach. (5 marks) d) A 10Base5 Thick Ethernet network cannot have more than 4 repeaters. Give at least two (2) reasons why. (4 marks) (Total marks: 15 marks)

QUESTION B4. a) Briefly describe the purpose of IP addresses falling under Class D and E. (2 marks) b) By assuming that these are classful IP addresses, find the network id and the host id of the following: i) ii) iii) iv)

105.43.12.7 192.15.10.5 30.67.12.1 129.23.4.0 (8 marks)

c) What is modulation? Briefly explain why modulation is needed for both digital and analog signals. (5 marks) (Total marks: 15 marks)

Diploma Part 2

Asia Pacific Institute of Information Technology

200801

Networks and Networking

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QUESTION B5 a) Explain how bridge could segment a network and describe why segmenting is important. (4 marks)

b) Explain three (3) improvements provided by frame relay technology in response to different demands of WAN users. (3 marks)

c) Briefly explain the encapsulation and decapsulation process in the data transmission. Use OSI model to help with the explanation. (8 marks) (Total marks: 15 marks)

Diploma Part 2

Asia Pacific Institute of Information Technology

200801