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Class 8 Computer Science — The boxes that make a network work

Work out what a hub, a switch, a router, a modem and an access point each do, and choose the one a job needs.

Name: ________________________

  1. 1.Two computers stand in the same room and are plugged into the same switch. One sends the other a file. Does the file pass through the router at the edge of the building?

    • a) No — both machines are on the same network, so the switch can deliver it by itself
    • b) Yes — every message a computer sends passes through the router
    • c) No — a message between two computers uses no device at all
    • d) Yes, because the router holds the list of which machine is which

  2. 2.A hub copies every message out to every other machine plugged into it. Four computers are on one hub, and each of the four sends one message. How many copies arrive at machines altogether?

  3. 3.A school has two buildings, and each building has a network of its own. Messages now need to travel between the two. Which device does that job?

    • a) A router
    • b) A longer cable and nothing else
    • c) A switch
    • d) A hub

  4. 4.A switch sends a message out to the one machine it is addressed to and to nobody else. Eight computers are plugged into a switch, and one sends a message meant for a second. How many computers receive a copy of it?

  5. 5.Ten computers are plugged into one hub, which copies every message out to every other machine. The hub is swapped for a switch, which sends a message only to the machine it is addressed to. One computer now sends one message. How many fewer copies leave the device than before?

  6. 6.A lab already has a switch with every computer cabled to it. An access point is added. What can the lab do now that it could not do before?

    • a) Reach a second network on the other side of the school
    • b) Push messages along the existing cables faster than before
    • c) Stop a copy of every message going to every machine
    • d) Let a device with no cable of its own join the network

  7. 7.A hub copies every message it receives out to every other machine plugged into it. Eight computers are plugged into one hub, and one of them sends a message meant for a second. How many computers receive a copy of it?

  8. 8.A lab with twenty machines has its hub taken out and a switch put in its place, and everything suddenly runs faster. What is the reason?

    • a) Far fewer copies of each message are being put on the cables, so there is less traffic to get through
    • b) A switch is built with thicker cables than a hub is
    • c) A switch sits closer to the machines than a hub does
    • d) A switch keeps a copy of every message so nothing ever needs sending twice

Answer key — Class 8 Computer Science — The boxes that make a network work

  1. 1. a) No — both machines are on the same network, so the switch can deliver it by itself
  2. 2. 12
  3. 3. a) A router
  4. 4. 1
  5. 5. 8
  6. 6. d) Let a device with no cable of its own join the network
  7. 7. 7
  8. 8. a) Far fewer copies of each message are being put on the cables, so there is less traffic to get through