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Class 8 Computer Science — The shapes a network is built in

Work out how much cable a bus, star, ring or mesh needs, and what a single break costs each of them.

Name: ________________________

  1. 1.In a mesh every computer has a cable to every other one. Match each mesh to the number of cables it needs.

    • 3 computers
    • 8 computers
    • 9 computers
    • 10 computers
    • 12 computers
    • 28
    • 3
    • 66
    • 36
    • 45

  2. 2.In a mesh, every computer has a cable to every other one. How many cables run from one single computer in a mesh of seven?

  3. 3.Six computers are joined in a star. Each one has a single cable running to the switch in the middle, and no other cables at all. How many cables does the network use?

  4. 4.In a star network each computer has one cable of its own to the switch in the middle. One of those outer cables is cut. What happens?

    • a) The switch is cut off but the computers can still reach each other
    • b) Every computer on the network is cut off from every other one
    • c) The computer on the far end of that cable is cut off, and the rest carry on as before
    • d) Nothing changes at all, because messages take a different route

  5. 5.Put these networks in order by how many cables each one uses, fewest first.

    • A bus joining four computers along one long cable
    • A star joining four computers to a switch
    • A mesh joining five computers
    • A mesh joining four computers

  6. 6.Five computers are joined in a mesh, so every computer has its own cable to every other computer. How many cables is that altogether?

  7. 7.A full mesh is almost never used for a large office. What is the reason?

    • a) The number of cables climbs far faster than the number of computers does
    • b) No more than four computers can ever be joined in a mesh
    • c) A mesh can only carry a message in one direction round the office
    • d) A mesh stops working the moment a single cable is cut

  8. 8.A star has eight computers around one switch. The switch itself stops working. How many of the eight can still reach another computer?

Answer key — Class 8 Computer Science — The shapes a network is built in

  1. 1. 3 computers → 3; 8 computers → 28; 9 computers → 36; 10 computers → 45; 12 computers → 66
  2. 2. 6
  3. 3. 6
  4. 4. c) The computer on the far end of that cable is cut off, and the rest carry on as before
  5. 5. 1. A bus joining four computers along one long cable 2. A star joining four computers to a switch 3. A mesh joining four computers 4. A mesh joining five computers
  6. 6. 10
  7. 7. a) The number of cables climbs far faster than the number of computers does
  8. 8.
    • 0
    • none