Year 9 Computing — 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.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) A switch keeps a copy of every message so nothing ever needs sending twice
- b) A switch is built with thicker cables than a hub is
- c) Far fewer copies of each message are being put on the cables, so there is less traffic to get through
- d) A switch sits closer to the machines than a hub does
2.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) Yes, because the router holds the list of which machine is which
- b) No — a message between two computers uses no device at all
- c) No — both machines are on the same network, so the switch can deliver it by itself
- d) Yes — every message a computer sends passes through the router
3.A home has one box that joins its computers to each other, hands messages on to the outside world, and plugs into the line coming into the house. Someone says the home therefore has no modem. What is wrong with that?
- a) A box that joins computers to each other can never plug into a line
- b) A home has no need for a modem at all
- c) A modem and a router are two names for exactly the same job
- d) One box can do several jobs at once, and the part talking to the line is doing a modem's job
4.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?
5.A message is sent from a computer in a lab to a machine on a network far away. Put these in the order the message reaches them.
- The computer that sends the message
- The router at the edge of the building
- A network outside the building
- The switch that computer is plugged into
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) Push messages along the existing cables faster than before
- b) Stop a copy of every message going to every machine
- c) Let a device with no cable of its own join the network
- d) Reach a second network on the other side of the school
7.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?
8.Match each device to the job it does.
- A hub
- A switch
- A router
- A modem
- An access point
- Delivers a message to the one machine it is addressed to
- Turns signals into a form that can travel down the line to the outside world
- Repeats everything it hears out to everything plugged into it
- Hands messages on between two different networks
- Lets a device with no cable of its own join the network
Answer key — Year 9 Computing — The boxes that make a network work
- 1. c) Far fewer copies of each message are being put on the cables, so there is less traffic to get through
- 2. c) No — both machines are on the same network, so the switch can deliver it by itself
- 3. d) One box can do several jobs at once, and the part talking to the line is doing a modem's job
- 4. 12
- 5. 1. The computer that sends the message 2. The switch that computer is plugged into 3. The router at the edge of the building 4. A network outside the building
- 6. c) Let a device with no cable of its own join the network
- 7. 1
- 8. A hub → Repeats everything it hears out to everything plugged into it; A switch → Delivers a message to the one machine it is addressed to; A router → Hands messages on between two different networks; A modem → Turns signals into a form that can travel down the line to the outside world; An access point → Lets a device with no cable of its own join the network