B.V Patel Institute of Business Management, Computer & Information Technology,UTU

Transcription

1 Fundamentals of Computer Networks Unit-1 Introduction Short Question 1. How error controls services is differ in data link layer and transport layer? 2. Give the full form of following: a. ANSI b. ICE c. ITU d. IEEE e. ISO 3. Identify five components of data communication system. 4. Which organization consists of computer scientist and engineers is known for its development of LAN standards? 5. Match the following to one or more layers of OSI model: a. Establishes, Manages and terminate sessions b. Ensure reliable transmission of data c. Log-in and log-out procedures d. Provides independence from differences in data representation e. Flow control f. Define frames g. Routing 6. Which are the various ways in which the wires can be run to link computers together? If there is a single path between source host and destination host, does it need a router between the two hosts? Why? 7. Differentiate between active hub and passive hub. 8. Enlist different category of Network. 9. For n devices in a network, what is the number of cable links required for a mesh, ring, bus and star topology? 10. Enlist all types of transmission impairment. 11. Assume six devices are arranged in a mesh topology. How many cables and ports (for each device) are needed? 12. What is the main function of session layer? Figure In figure 1.0 what happens if one of the stations is unplugged? 14. Which components are required in data communication? 15. Enlist protocols that work at application layer. 1

2 Long Question 1. Explain each component of data communication. 2. Why topology is required in network? For each of following four different networks, discuss the consequences if a connection fails. a. Six devices arranged in a bus topology b. Five devices arranged in mesh topology c. Four devices arranged in a ring topology d. Seven devices arranged in a star topology (without the hub) 3. Describe star topology with its advantage and disadvantage. 4. Explain each layer of OSI model. 5. Write note on standard and standards organization. 6. OSI Model is layered architecture. Justify. 7. Which layer is responsible for Routing? Explain it with all its responsibility. 8. Describe the fundamental characteristics for data communication and explain each of them. 9. At which layer encryption & decryption does? Explain it with its other responsibilities in detail. 10. List roles and responsibilities of Data link layer and network layer. Explain any two of each in detail. Multiple Choice Questions 1. Where is a hub specified in the OSI model? a) Session layer b) Physical layer c) Data Link layer d) Application layer 2. Which transmission mode is used for television broadcast? a) Simplex b) Half-Duplex c) Full-Duplex d) Automatic 3. The following is used to interconnect workstation distributed around office within a single building or group of building. a) LAN b) MAN c) WAN d) Wireless 4. Which of the following protocol suite for the current Internet? a) UNIX b) TCP/IP c) ACM d) NCP 2

3 5. Which of the following is an application layer service? a) Dialog control b) Service point addressing c) Network virtual terminal d) Flow control 6. In which of the following topology, if a cable (act as a backbone) break then stops all transmission? a) Mesh b) Bus c) star d) primary 7. defines how a particular pattern to be interpreted, and what action is to be taken based on that interpretation. a) Semantics b) Syntax c) Timing d) Attenuation 8. How many layers are in the TCP/IP model? a) 4 layers b) 5 layers c) 6 layers d) 7 layers 10. Physical or logical arrangement of network is a) Topology b) Routing c) Networking d) Modem 11. Frequencies of failure and network recovery time after a failure are measures of the of a network. a) Performance b) Reliability c) Feasibility d) Security 11. In which of the transmission mode, the channel is shared by both communicating devices at all times? a) Performance b) Reliability c) Feasibility d) Security True/False 3

4 1. In star topology all computers are connected to each other with individual cable. 2. A server in network will use and provide network resources. 3. In star topology all computers are connected with single backbone cable. 4. Internet is a network of network. 5. MAN is cover inside a town or city. 6. In broadcasting only one can send and more than one can receive. 7. Wide area network are connected across a distance of less than 30 miles. 8. Networks cannot extend beyond the boundaries of a building. 9. LANs typically connect separate offices in the same organization, whether they are across town or around the world from each other. 10. Each network device must have a unique address so that data can be transmitted reliably to and from that device. 11. A MAN is a network with a size between a LAN and a WAN. 12. The standard used for wireless LANS is IEEE The combination of LANs and MANs is known as WAN. 14. The main purpose of each layer is to give services to lower layer. 15. In connection oriented service, the source and destination have a fixed path. Fill in the blanks: 1. A in a network is dedicated to performing specific task in network. 2. If a computer on the network shares resources for others to use, it is called. 3. In topology, if a computer s network cable is broken, whole network goes down. 4. Terminators are used in topology. 5. layer is used to determine signal type: analog or digital. 6. All computers are connected to a single device is called topology. 7. In topology all computers are connected to each other with individual cable. 8. Number of links to connect n nodes in a mesh topology is =. 9. In Ring Topology, Repeater works in 3 modes:, and. 10. Three main categories of networks are, and. Short Question Unit-2 Communication media & data transmission 1. Draw diagram showing the transmission media classification. 2. What is the position of the transmission medium in OSI model? 3. What is the significance of the twisting in twisted-pair cable? 4. Differentiate between modulation and demodulation. 5. List an unguided media with their respective frequency. 4

5 6. Enlist at least 3 names of guided media. 7. Which parameter is used to measure the thickness of wire? 8. Fiber optic provides greater immunity to tapping. Justify. 9. What is the purpose of cladding in a fiber optic cable? 10. Differentiate between analog data and digital data. 11. State the meaning of sky propagation. 12. What is the major factor that makes coaxial cables less susceptible to noise than twisted pair cables? 13. Name the TCP/IP protocol is used for transferring electronic mail messages from one machine to another. 14. Differentiate between omnidirectional waves and unidirectional waves? Long Question 1. Explain propagation modes of fibre optics signal in detail. 2. State the difference between guided media & unguided media. 3. What are differences between STP & UTP cable? 4. Write characteristics of twisted pair cables and list out two merits of it. 5. What are the selection criteria for different guided media? State the use of each guided media. 6. Note advantage of radio wave and disadvantage of radio wave in brief. 7. Write a note on unguided media. Briefly explain any two unguided media. 8. Explain the principle used in optical fiber for transmission of signals. How does it differ from twisted pair cable? 9. Write characteristics of Infrared and list out two merits of it. 10. Note advantage of micro wave and disadvantage of it in brief. Multiple Choice Questions 1. Which protocol is used to associate logical address to physical address? a) ICMP b) ARP c) RARP d) UDP 2. Which agency developed standards for electrical connections and the physical transfer of data between devices? a) EIA b) ITU-T c) ANSI d) ISO 3. Which cable consists of an inner copper core and a second conducting outer sheath? a) Twisted-pair b) Coaxial c) Fiber-optic d) Shielded twisted-pair 4. In which cable attenuation increases with frequency increase above 100 khz? 5

6 a) Ethernet cable b) Coaxial cable c) Twisted pair cable d) Fiber optic cable 5. Which of the following primarily uses guided media? a) Cellular telephone system b) Local telephone system c) Satellite communications d) Radio broadcasting 6. Which of the following is not a guided medium? a) Twisted-pair cable b) Coaxial cable c) Fiber-optic cable d) Atmosphere 7. What is the major factor that makes coaxial cable less susceptible to noise than twisted-pair cable? a) Inner conductor b) Diameter of cable c) Outer conductor d) Insulating material 8. Radio communication frequency range from a) 3 KHz to 300 KHz b) 300 KHz to 3 GHz c) 3 KHz to 300 GHz d) 3KHz to 3000 GHz 9. When a beam of light travels through media of two different densities, if the angle of incidence is greater than the critical angle, occurs. a) Reflection b) Refraction c) Incidence d) Criticism 10. Signals with a frequency below 2 MHz use which propagation? a) Ground b) Sky c) Line-of-sight d) Parallel 11. Which cable consists of two insulated copper wires twisted together? a) Coaxial b) Fiber-optic c) Twisted-pair d) Thin 12. Which cable consists of a central conductor and a shield? a) Coaxial b) Fiber-optic 6

7 c) Twisted-pair d) Thin 13. Which cables are composed of a glass or plastic inner core surrounded by cladding, all encased in an outside jacket? a) Coaxial b) Fiber-optic c) Twisted-pair d) Thick 14. In a fiber-optic cable, the signal is propagated along the inner core by. a) Reflection b) Refraction c) Modulation d) All of the above 15. Which of the following are used for short-range communications such as those between a PC and a peripheral device? a) Radio waves b) Microwaves c) Infrared waves d) Serial waves True/False 1. In twisted pair both wires are used to carry signals to receiver. 2. The most common UTP connector is RG The most common cable used in communication is referred to as unshielded twisted pair. 4. Gauge is a measure of the thickness of the wire. 5. Coaxial cables are categorized by their RG (radio government). 6. RG-59 with impedance 75Ω is used in Cable TV. 7. In Coaxial cable, propagation modes of signal can be step index or graded index. 8. SC connector is used for cable TV. 9. In, Line-of-sight propagation, very higher-frequency signals are transmitted in straight lines directly from antenna to antenna. 10. Radio frequency range between 1 and 300GHz. 11. Microwave frequency range between 1 and 300GHz. 12. Radio waves are omnidirectional. 13. Data cannot be corrupted during transmission. 14. Radio waves are used for unicast. 15. In block coding, we divide our message into blocks, each of k bits, called codewords. Fill in the Blanks 1. can be broadly defined as anything that can carry information from a source to a destination. 2. The most common twisted-pair cable user in communication is referred to as 7

8 . 3. IBM has produced a version of twisted-pair cable for its use called. 4. The most common UTP connector is. 5. A twisted pair consists of two, each insulated with its own plastic insulation. 6. In telecommunications, transmission media can be divided into two broad categories namely &. 7. are those that provide a conduit from one device to another. 8. is a cable that accepts and transports signals in the form of light. 9. Coaxial cables are categorized by their ratings. 10. To connect coaxial cable to devices, the most common connector used today is. 11. mode carries multiple beams from a light source move through the core in different paths. 12. mode uses a step-index fiber and a highly focused source of light that limits beams to a small range of angles, all close to horizontal. 13. Whenever bits flow from one point to another, they are subject to unpredictable changes because of. 14. The term means that only 1 bit of a given data unit is changed from 1 to 0 or 0 to A/An code can detect only the types of errors for which it is designed; other types of errors may remain undetected. 16. In block coding, we divide our message into blocks, each of k bits, called. 17. To detect or correct errors, we need to send bits with data. 18. Coding scheme is divided into two broad categories namely &. 19. The term means that 2 or more bits in the data unit have changed from 1 to 0 or from 0 to is the process of adding 1 extra byte whenever there is a flag or escape character in the text. 8