Categories
Class 12

Computer Networking

Very Short Answer Questions

  1. Define a network. What is its need?
    A network is an interconnected collection of autonomous computers. We need networking for resource sharing and as a communication medium.
  2. Write two advantages and disadvantages of networks.
    Advantages:
    a) It allows resource sharing.
    b) It acts as a communication medium.
    Disadvantages:
    a) It makes the system more complicated.
    b) File security becomes more important.
  3. A school with 20 standalone computers is considering networking them together and adding a server. State 2 advantages of doing this.
    Advantages:
    a) Resources can be shared easily.
    b) Software can be shared easily.
  4. What is a communication channel? Name the basic types of communication channels available.
    Communication channel means connecting cables/media. The cables that connect two or more workstations are the communication channels. The basic types of communication channels are:
    a) Twisted pair cable
    b) Coaxial cable
  5. What is MAC address?
    MAC address refers to the physical address assigned by NIC manufacturer.
  6. What is IP address?
    IP address is the unique series of numbers, uniquely identifying a computer in a network.
  7. What is MAC address? What is the difference between MAC address and an IP address?
    MAC address refers to the physical address assigned by NIC manufacturer. MAC address is a 6-byte address with each byte separated by a colon. Whereas each IP address is a 32-bit address, which is a series containing four numbers separated by dots or periods.
  8. What is a domain name? How is it alternatively known?
    The domain name is a unique name assigned to a website. It is alternatively known through its IP address.
  9. How is a domain name related to an IP address?
    Domain name is related to an IP address because every computer connected to the Internet has an IP address. Therefore, different websites on the Internet also have their unique IP address.
  10. What are the various types of networks?
    There are 4 types of networks:
    a) LAN (Local Area Network)
    b) MAN (Metropolitan Area Network)
    c) WAN (Wide Area Network)
    d) PAN (Personal Area Network)
  11. What is the difference between MAN and WAN?
    MAN spreads over a city but WAN spreads across countries.
  12. What is meant by topology? Name some popular topologies.
    The pattern of interconnection of nodes in a network is called topology. Star, Bus, Ring, Tree, Graph and Mesh are some of the popular topologies.
  13. What are the factors that must be considered before making a choice for the topology?
    Following are the factors:
    a) It should be cost effective.
    b) It should be flexible.
    c) It should be reliable.
  14. What are the similarities and differences between bus and tree topologies?
    The transmission in both bus and tree topology is same. In both cases, there is no need to remove packets from the medium because when a signal reaches the end of the medium, it is absorbed by the terminators.
    Bus topology consists of a single length of the transmission medium onto which, various nodes are attached. But in Tree topology, the shape of the network is that of an inverted tree with the central root branching and sub-branching to the extremities of the network.
  15. Give two characteristics of Star Topology. Also, show it using a diagram with interconnection of 5 computers.
    Two characteristics:
    a) It consists of a central node to which all other nodes are connected by a single path.
    b) It is used in most existing information networks involving data processing or voice communications.
    Star Topology
  16. What are the limitations of star topology?
    Limitations:
    a) It requires a long cable.
    b) It is difficult to expand.
  17. Write one advantage of star topology over bus topology and one advantage of bus topology over star topology.
    Advantage of star topology over bus topology is that fault diagnosis is easier in star topology.
    Advantage of bus topology over star topology is that bus topology is easier to extend.
  18. When do you think, ring topology becomes the best choice for a network?
    Ring topology becomes the best choice for a network when optical fibers are used for high speed transmission.
  19. Write the two advantages and two disadvantages of bus topology in a network.
    Two advantages:
    a) Short cable length needed.
    b) Easy to extend.
    Two disadvantages:
    a) Fault diagnosis is difficult.
    b) Nodes must be intelligent.
  20. Briefly mention two advantages and disadvantages of star topology in a network.
    Two advantages:
    a) Easy problem diagnosis.
    b) Provides easy access for service.
    Two disadvantages:
    a) Requires long cable length.
    b) It is difficult to expand.
  21. Give two advantages and two disadvantages of following network topologies:
    a) Star
    Two advantages:
    i) Easy problem diagnosis.
    ii) Provides easy access for service.
    Two disadvantages:
    i) Requires long cable length.
    ii) It is difficult to expand.
    b) Tree
    Two advantages:
    i) Shorter cable length needed.
    ii) Easy to extend.
    Two disadvantages:
    i) Fault diagnosis is difficult.
    ii) Fault isolation is difficult.
  22. Give two advantages and disadvantages of following network topologies:
    a) Bus
    Two advantages:
    a) Short cable length needed.
    b) Easy to extend.
    Two disadvantages:
    a) Fault diagnosis is difficult.
    b) Nodes must be intelligent.
    b) Tree
    Two advantages:
    i) Shorter cable length needed.
    ii) Easy to extend.
    Two disadvantages:
    i) Fault diagnosis is difficult.
    ii) Fault isolation is difficult.
  23. Write two advantages and disadvantages of the following:
    a) Optical fibres
    Advantages:
    i) It is immune to electrical and magnetic interference.
    ii) It has a very high transmission capacity.
    Disadvantages:
    i) Difficult to install.
    ii) Connection losses are common problems.
    b) Satellites
    Advantages:
    i) Area coverage is large.
    ii) Best alternative where laying cable is difficult.
    Disadvantages:
    i) High investment cost.
    ii) High atmospheric losses above 30 GHz limit carrier frequencies.
    c) Microwaves
    Advantages:
    i) Cheaper than digging trenches for laying cables.
    ii) Offers freedom from land acquisition rights.
    Disadvantages:
    i) It is insecure.
    ii) Susceptible to weather effects.
  24. A company has 3 departments namely Administrative, Sales, Production. Out of Telephone Cable, Optical Fiber, Ethernet Cable, which communication medium is best for high speed communication between departments?
    Optical Fiber is best suited for high speed communication between departments.
  25. Write two disadvantages of twisted pair cables.
    Disadvantages:
    a) Low bandwidth.
    b) Incapable of carrying signal over long distances without using repeaters.
  26. Which of the following is/are not communication medium?
    a) Optical fiber cable (Yes)
    b) Coaxial cable (Yes)
    c) Microwave (Yes)
    d) LAN (No)
    Out of the above, write the names of wired communication media.
    Optical fiber cable and coaxial cable are wired communication media.
  27. Define the following:
    a) Hub: It is a hardware device used to connect several computers together.
    b) Switch: It is a device that is used to segment networks into different sub-networks called subnets or LAN segments.
  28. What is the use of repeater in a network? How is it different from hub?
    A repeater is used to amplify a signal that is being transmitted on the network. It is different from hub because a hub is used to connect several computers together.

Short Answer Questions

  1. What is a network? What are its goals and applications?
    A network is an interconnected collection of autonomous computers.
    Goals of network:
    a) Resource sharing
    b) Reliability
    c) Cost factor
    d) Communication medium
    Applications of network:
    a) Sharing peripherals, information, distributed control
    b) Access to remote database
    c) Communication facilities
  2. What do you understand by Domain Name Resolution?
    Domain Name Resolution refers to the process of obtaining corresponding IP address from a domain name.
  3. What are communication channels? Discuss various communication channels available for networks.
    The cables that connect two or more workstations are the communication channels.
    Various communication channels:
    a) Twisted pair cable: It consists of two identical wires wrapped together in a double helix.
    b) Coaxial cable: It consists of a solid wire core surrounded by one or more foil or wire shields, each separated by some kind of plastic insulator.
    c) Optical fibers: It consists of thin strands of glass or glass-like material which are so constructed that they carry light from a source at one end of the fiber to a detector at the other end.
  4. Write some advantages and disadvantages of the following:
    a) Optical fibers
    Advantages:
    i) Immune to electrical and magnetic interference.
    ii) Suitable for harsh industrial environments.
    Disadvantages:
    i) Installation problem.
    ii) Connection losses are common problems.
    b) Coaxial cables
    Advantages:
    i) Data transmission is better than twisted pair cable.
    ii) Suitable for broadband transmission.
    Disadvantages:
    i) Expensive.
    ii) Not compatible with twisted pair cables.
    c) Twisted pair cables
    Advantages:
    i) Simple.
    ii) Easy to install and maintain.
    Disadvantages:
    i) Incapable of carrying signal over long distances without using repeaters.
    ii) Has low bandwidth capabilities.
    d) Radio waves
    Advantages:
    i) It offers mobility.
    ii) Cheaper than digging trenches for laying cables.
    Disadvantages:
    i) Insecure.
    ii) Susceptible to weather effects.
    e) Microwaves
    Advantages:
    i) Cheaper than digging trenches for laying cables.
    ii) Offers freedom from land acquisition rights.
    Disadvantages:
    i) Insecure.
    ii) Susceptible to weather effects.
    f) Satellites
    Advantages:
    i) Area coverage is large.
    ii) Useful for sparsely populated areas.
    Disadvantages:
    i) High investment cost.
    ii) High atmospheric losses above 30 GHz limit carrier frequencies.
  5. Discuss and compare various types of networks.
    Various types of networks:
    a) LAN: Small computer network confined to a localized area.
    b) MAN: Networks that spread over a city.
    c) WAN: Networks that spread across countries.
    d) PAN: Small network of communication-capable devices within the range of an individual person.
  6. Explain various mostly used networks.
    Various types of networks:
    a) LAN: Small computer network confined to a localized area.
    b) MAN: Networks that spread over a city.
    c) WAN: Networks that spread across countries.
    d) PAN: Small network of communication-capable devices within the range of an individual person.
  7. Discuss the factors that govern the selection of a topology for a network.
    Following factors:
    a) Considering how crucial the work is.
    b) Cost
    c) Length of cable needed
    d) Future growth
    e) Communication media
  8. Compare and contrast:
    a) Star and bus topologies
    Star uses long cable length whereas bus uses shorter cable length.
    Problem diagnosis is easy in star, but difficult in bus.
    b) Star and tree topologies
    Star uses long cable length whereas tree uses shorter cable length.
    Problem diagnosis is easy in star, but difficult in tree.
    c) Bus and ring topologies
    Both bus and ring requires short cable lengths.
    Bus is not suitable for optical fibers, but ring is.
  9. What is the role of modem in electronic communications?
    A modem allows us to connect and communicate with other computers via telephone lines.
  10. What are hubs? What are its types?
    A hub is a hardware device, used to connect several computers together. Two types of hubs are active hubs and passive hubs.
  11. What is the role of a switch in a network?
    A switch is a device that is used to segment networks into different sub-networks called subnets or LAN segments.
  12. Briefly discuss the role of following devices in the context of networking:
    a) Repeater: It is a device that amplifies a signal being transmitted on the network. It is used in long network lines, which exceed the maximum rated distance for a single run.
    b) Gateway: It is a device that connects dissimilar networks. It operates at the highest layer of network abstraction.
  13. What are the common threats to network security?
    Common threats:
    a) Snooping
    b) Eavesdropping
    c) Denial of Access to Information
    d) Denial of Access to Applications
    e) Denial of Access to Systems
    f) Denial of Access to Communications
  14. What are Denial of Services attack?
    Denial of Services attacks are those attacks that prevent the legitimate users of the system, from accessing or using the resources, information, or capabilities of the system.
  15. How can you prevent/counter threats to network security?
    Preventive measures:
    a) Authorization.
    b) Authentication.
    c) Firewall.
    d) Intrusion detection.
    e) Implement proper security policy for the organization.
    f) Use proper file access permissions when sharing files on the Internet.
  16. Which of the following units measures the speed with which data can be transmitted from one node to another node of a network? Also give the expansion of the suggested unit.
    a) KMph
    b) KMpl
    c) Mbps
    Mbps (Megabits per second)
  17. Identify the type of topology from the following:
    a) If each node is connected with the help of independent cable with the help of a central switching (communication controller)
    Star topology
    b) If each node is connected with the help of a single coaxial cable.
    Bus topology

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