Stretch tasks Computer Networks and Topologies

Round 1: Quiz Blitz

1. A network on one site, using hardware the organisation owns Geography and ownership: one site, and the organisation owns the hardware.
2. It crosses land the organisation does not own Sites in different towns are joined over land the organisation cannot cable itself.
3. A router A router joins networks together and directs packets between them.
4. switch Every device has its own cable running to the switch.
5. True Every device depends on the one shared cable.
6. False The switch is one: if it fails, the whole network stops.
7. Two devices sent at once, so both must wait and send again Only one device can transmit on the shared cable at a time.
8. More secure: an attacker needs access to the cable; More consistent speed, with less interference Cable is harder to intercept and is not affected by walls or other networks.
9. MAC address filtering A MAC address can be faked, so filtering only raises the effort.
10. Sends it only to the device it is addressed to That is why a star network with a switch is fast and private.
11. Its network interface card The address is built into the network interface card.
12. the internet It spans the world over infrastructure owned by many providers.

Round 2: Quick Fire

1. • A LAN covers one site, with hardware the organisation owns
   • A WAN spans a large area using infrastructure hired from a provider
   Model answer

   A LAN covers a small area on a single site, and the organisation owns the hardware. A WAN covers a large geographical area, joining sites in different towns or countries, using infrastructure hired from a telecommunications provider.

2. • In a star, each device has its own dedicated cable
   • On a bus, devices share one cable, so they collide and must wait
   Model answer

   In a star, each device has its own dedicated cable to the switch, so it competes with nothing. On a bus, every device shares one backbone cable and only one can transmit at a time, so when it is busy there are collisions and devices must wait and send again.

3. • A wireless signal travels through the air, where anyone in range can receive it
   • To intercept wired data, an attacker needs physical access to the cable
   Model answer

   A wireless signal travels through the air as radio waves, so anyone within range can receive it. To intercept data on a wired connection, an attacker needs physical access to the cable itself.

4. • A switch connects devices within one network
   • A router connects networks together, such as a LAN to the internet
   Model answer

   A switch connects devices within one LAN, forwarding each frame only to the device it is addressed to. A router connects different networks together and directs packets between them, for example joining a LAN to the internet.

Round 3: Big Think

1. • A star gives each device its own cable to a switch
   • So a star is faster, with no collisions
   • One broken cable affects only that device
   • But a star costs more, and the switch is a single point of failure
   • A bus shares one backbone cable
   • So a bus is cheaper, with less cable and no central device
   • But a bus is slow when busy, and a backbone break stops everything
   • A reasoned recommendation, such as a star being worth the small extra cost
   Model answer

   A star gives every computer its own dedicated cable to a switch, so it is faster, with no collisions, and if one cable fails only that device is affected. However, it needs more cable and a switch, so it costs more, and the switch is a single point of failure. A bus shares one backbone cable, so it is cheaper, with less cable and no central device, but it is slow when busy because of collisions, and a break in the backbone stops the whole network. I would use a star: for six computers the extra cost is small, and it is worth paying for the speed and reliability.

2. • Wireless is convenient: phones and laptops connect without cables
   • Wireless is cheap and quick to install
   • Wireless is less secure, because anyone in range can receive it
   • Wireless is slower and suffers interference
   • A wired link suits the tills: fast, reliable and secure for payments
   • Use encryption such as WPA2 or WPA3
   • Set a strong password on the access point, not the default
   • MAC address filtering, which raises the effort even though it can be spoofed
   Model answer

   Wireless is convenient for customers, because their phones and laptops can connect without cables, and it is cheap and quick to install. However, it is slower and less consistent, suffers interference from walls and other networks, and is less secure because anyone in range can receive the signal. The tills should use wired connections, because card payments need a fast, reliable link that an attacker could only intercept with physical access to the cable. The wireless network should use WPA3 encryption, a strong password on the access point rather than the default, and MAC address filtering for staff devices, which raises the effort even though a MAC address can be spoofed.

This or That

1. LAN One site and hardware the school owns make it a LAN.
2. A router A switch connects devices within one network. A router joins networks.
3. Bus One shared backbone uses far less cable than one cable per device.
4. Only that device loses its connection Each device has its own cable, so the failure stays local. Only the switch failing stops everything.
5. A wired connection An attacker needs physical access to a cable, but a radio signal reaches anyone in range.
6. No: a MAC address can be spoofed It raises the effort, so it is used alongside encryption and a strong password.
7. A switch On a bus, every frame travels past every device, which is also less secure.
8. A WAN It spans the world over infrastructure from many providers: the largest WAN of all.

Memory Match

• A 2 LAN: One site, hardware owned by the organisation
• B 3 WAN: Spans sites using hired infrastructure
• C 6 Router: Joins networks and directs packets between them
• D 5 Switch: Forwards each frame only to its destination
• E 1 Bus topology: Every device shares one backbone cable
• F 4 Star topology: Each device has its own cable to the centre

Sort It

1. Bus Every device shares one backbone cable That shared cable is what makes a bus.
2. Bus Cheap, because it uses little cable One cable and no central device keep a bus cheap.
3. Bus Needs a terminator at each end Terminators sit at the two ends of the backbone.
4. Star Costs more, because it needs a switch and lots of cable Every device needs its own cable, and a switch is required.
5. Bus Collisions happen when two devices send at once Only one device can use the shared cable at a time.
6. Bus Every frame travels past every device That makes a bus less secure.
7. Star If the central device fails, everything stops The switch is a star's single point of failure.
8. Star Adding a device means running one more cable to the centre A star grows one cable at a time.
9. Star Every device has its own cable to a switch Dedicated cables to a central switch make a star.
10. Star One broken cable affects only one device In a star, each cable serves one device.
11. Bus A break in the backbone stops the whole network The backbone is a bus's single point of failure.