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Year 9 Computing — Addresses and names on a network

Read a machine's address, work out which machines share a network, and say what turns a name into an address.

Name: ________________________

  1. 1.Which of these is a name service's job rather than a router's?

    • a) Joining two different networks together
    • b) Saying which number belongs to a given name
    • c) Carrying a message out of the building
    • d) Choosing which network to hand a message on to next

  2. 2.Machines share a network when the first three of their four numbers match. One machine is at 172.20.1.5 and another is at 172.20.9.5. What has to happen for a message to get from one to the other?

    • a) It has to be handed to a router, because the two are not on the same network
    • b) One of them has to change its address so that all four numbers match
    • c) Nothing out of the ordinary — they are already on the same network
    • d) The two machines have to swap names with each other first

  3. 3.Two machines share a network when the first three of their four numbers are the same. Each of these machines is sending to the machine at 192.168.4.9. Sort each sender by whether its message stays on one network.

    Groups: Stays on one network · Crosses to another network

    • 10.0.4.9
    • 192.168.4.1
    • 192.168.4.40
    • 172.16.4.9
    • 192.168.7.40
    • 192.168.4.200

  4. 4.Every address on one network begins 10.4.2, and the last number may be anything from 20 to 90. How many machines can that network hold?

  5. 5.Two different machines on one network are given the same address by mistake. What goes wrong?

    • a) The network runs more slowly, but everything still arrives where it should
    • b) Nothing goes wrong, because an address is allowed to be shared
    • c) Both machines stop working altogether until one is unplugged
    • d) Messages meant for one of them can arrive at the other, because the address no longer says which machine is which

  6. 6.Machines share a network when the first three of their four numbers match. Match each machine to the network it is on.

    • 192.168.1.7
    • 192.168.2.7
    • 10.1.1.7
    • 172.16.5.7
    • 10.1.2.7
    • 192.168.2
    • 192.168.1
    • 10.1.2
    • 10.1.1
    • 172.16.5

  7. 7.Each of the four numbers in an address is held in one byte, so it runs from 0 up to the largest value one byte can hold. Which point on the line is that largest value?

    Mark the line with an X.

    0306090120150180210240270

  8. 8.A website is moved onto a different machine with a different address, and keeps the name it always had. What has to be changed so that people can still reach it?

    • a) Every browser in the world, one at a time
    • b) What the name service answers when it is asked about that name
    • c) The address of the computer belonging to each person visiting
    • d) The name itself, so that it matches the new machine

Answer key — Year 9 Computing — Addresses and names on a network

  1. 1. b) Saying which number belongs to a given name
  2. 2. a) It has to be handed to a router, because the two are not on the same network
  3. 3. 192.168.4.40 → Stays on one network; 192.168.7.40 → Crosses to another network; 192.168.4.200 → Stays on one network; 10.0.4.9 → Crosses to another network; 192.168.4.1 → Stays on one network; 172.16.4.9 → Crosses to another network
  4. 4. 71
  5. 5. d) Messages meant for one of them can arrive at the other, because the address no longer says which machine is which
  6. 6. 192.168.1.7 → 192.168.1; 192.168.2.7 → 192.168.2; 10.1.1.7 → 10.1.1; 172.16.5.7 → 172.16.5; 10.1.2.7 → 10.1.2
  7. 7. 255
  8. 8. b) What the name service answers when it is asked about that name