Stretch tasks Networks and Topologies

Round 1: Quiz Blitz

1. Who owns the infrastructure A LAN's hardware is owned by the organisation. A WAN uses connections leased from telecoms companies.
2. Router A router works between networks. Your home router joins your LAN to the internet.
3. Switch A switch reads the destination MAC address, which cuts out unnecessary traffic.
4. True The central switch is a single point of failure.
5. No single point of failure; Data can be rerouted if a link fails Multiple routes make mesh very reliable, but a wired mesh is expensive and complex.
6. Peer to peer Peer to peer is cheap and simple, with no server to buy.
7. latency Latency is delay. Bandwidth is capacity.
8. Lets a device connect to a network Every network interface card has a unique MAC address.
9. False Bandwidth is how much data can flow per second. Latency is how long it takes to arrive.
10. If the server fails, users lose access; Servers and specialist staff are expensive The other three are disadvantages of peer to peer.
11. The bandwidth is shared between more devices Bandwidth is shared, so each device gets a smaller slice.
12. Fibre optic Fibre carries far more data, much further, and is immune to electrical interference.

Round 2: Quick Fire

1. • A LAN covers a small area, with hardware owned by the organisation
   • A WAN covers a large area, using infrastructure it does not own
   Model answer

   A LAN covers a small area, such as one building, and its hardware is owned by the organisation. A WAN covers a large area and uses infrastructure the organisation does not own, leased from telecommunications companies.

2. • It reads the destination MAC address of the data
   • And sends the data only to the device it is meant for
   Model answer

   A switch reads the destination MAC address of each frame and sends it only to the device it is intended for, not to every device on the network.

3. • A broken cable only affects that one device
   • Devices are easy to add or remove
   • Few collisions and good performance
   Model answer

   If one cable fails, only that device is affected. Devices are also easy to add or remove without disturbing anyone else.

4. • Bandwidth
   • The number of users
   • The transmission media
   • Errors and interference
   • Latency
   Model answer

   Bandwidth, and the number of users sharing it.

Round 3: Big Think

1. • A clear choice: client server
   • Central backup of everyone's work
   • Central management of accounts and updates
   • Central control of security and permissions
   • Users can log on at any computer to reach their files
   • Peer to peer is impractical at this scale
   • Weighs the drawback: cost, or the server failing
   Model answer

   Client server would be better for the school. With 500 computers, central backup is essential, so every student's work is backed up in one place. The network manager can manage accounts and install updates centrally, and set security permissions so students cannot see staff files. Files are stored centrally, so students can log on at any computer and reach their work. Peer to peer would be impractical: files would be spread across 500 machines that must be switched on, and each computer would need to be managed individually. Client server is more expensive, and if the server fails everyone loses access, but at this scale it is the best choice.

2. • Star: every device connects to a central switch
   • Star: if the central switch fails, the whole network fails
   • Star: a broken cable only affects one device
   • Star: easy to add devices, with few collisions
   • Mesh: devices connect to many others, so there are multiple routes
   • Mesh: data is rerouted, so there is no single point of failure
   • Mesh: expensive and complex to cable
   • Wireless mesh avoids the cabling
   Model answer

   In a star topology every device connects to a central switch. If one cable fails, only that device is affected, devices are easy to add, and there are few collisions. But if the central switch fails, the whole network fails, and it needs a lot of cable. In a mesh topology each device connects to many others, so there are multiple routes. If one connection fails, data is rerouted, so there is no single point of failure, which makes mesh more reliable. But a wired mesh is very expensive and complex to set up, which is why wireless mesh networks are now common.

This or That

1. A switch A switch delivers within a LAN. A router works between networks, using IP addresses.
2. A WAN It spans the world on infrastructure that no single organisation owns.
3. Mesh In a mesh, data can be rerouted. A star depends on its central switch.
4. The number of lanes on a motorway Bandwidth is capacity. Latency is the delay, like the journey time.
5. A client and a server at once Every peer shares its own files and uses everyone else's.
6. High latency Latency is delay, and it makes live, two-way applications feel unresponsive.
7. A wireless access point A WAP connects devices to the network using radio waves.
8. Fibre optic Fibre carries light, not electricity, so interference cannot affect it.

Memory Match

• A 6 LAN: Small area, hardware owned by the organisation
• B 4 WAN: Large area, using leased infrastructure
• C 5 Router: Joins networks, using IP addresses
• D 3 Switch: Delivers within a LAN, using MAC addresses
• E 1 NIC: Hardware that connects a device to a network
• F 2 Latency: The delay before data arrives

Sort It

1. Mesh Devices connect to many other devices In a full mesh, every device connects to every other.
2. Mesh Complex to set up and maintain So many connections take a lot of work to install and manage.
3. Mesh Data can take the fastest available route With many paths, data can avoid busy links.
4. Mesh Data can take another route if a link fails Multiple routes are the whole point of a mesh.
5. Star Very few collisions, because the switch directs traffic The switch sends each frame only where it needs to go.
6. Mesh No single point of failure If one connection fails, data is rerouted another way.
7. Star If the central switch fails, everything stops The switch is a single point of failure in a star.
8. Star A broken cable only cuts off one device Each device has its own cable to the switch.
9. Mesh Common in smart home Wi-Fi systems Wireless mesh avoids the cost of cabling.
10. Star Easy to add a device without disturbing anyone Just plug a new cable into the switch.
11. Star Every device connects to one central switch That central switch is what defines a star.