Protocols and Layers

• What are packets?


  Data split up into smaller pieces to be sent.
• Why are packets used?


  Because data files are too large to be sent in one go, therefore they are split up into packets that travel along different routes so that network can be used more efficiently.
• What are packets made of?


  The data itself, the sender and destination IP, and an order number.
• What may happen in the arrival of packets?


  They may arrive in the wrong order so they need to be re-ordered, or they may even fail to arrive, needing them to be re-sent.
• What is the ethernet?


  Main standard for wired networks - it is widely used so compatible with many devices.
• What are the properties of an ethernet?


  • High bandwidth
  • Inbuilt security
  • Reliable
  • Low purchase cost
• What does bandwidth do in wired networks?


  It depends on cable types - more bandwidth means higher speed.
• How is the installation of wired networks?

  More disruptive, as cables are needed to be installed.
• How is the cost of wired networks?


  They are expensive, as more hardware and more work are needed to set up.
• How is the security in wired networks?


  Good - in order to hack it, the hacker would need to physically plug into the network.
• How is the interference of wired networks?


  It is limited, as it is needed to be careful where cables are placed - for example, lighting cables can cause interference.
• How is portability in wired networks?


  Limited, as you cannot move far due to the cables.
• Wired networks have long range.
• What are some examples of wireless networks?

  Wi-Fi and bluetooth.
• What is Wi-Fi?


  Wireless technology using radio signals to connect devices to a network.
• What is the range of Wi-Fi?


  50 to 100 metres.
• What is Bluetooth?


  Wireless technology using radio signals to connect devices to each other.
• What is the range of Bluetooth?


  About 10 metres.
• How is bandwidth in wireless networks?


  Less bandwidth, meaning slower speeds.
• How is the installation of wireless networks?


  It is easy, as the only installation needed is a WAP, without extra cables.
• How is the cost of wireless networks? 


  Cheaper, as there is less hardware and work to set up.
• How is the security of wireless networks?


  Weaker, as anyone can pick up the signal and attempt to hack.
• How is interference in wireless networks?


  It can be a problem, as signals are affected by walls and electronic equipment, and can weaken with distance.
• How is portability in wireless networks?


  It is very mobile, the only requirement is to be within range.
• What is the range in wireless networks?


  More limited.
• What are some other benefits of wireless networks?


  More types of devices can connect, and fewer trip hazards from wires.
• What does encryption do in networks?


  Scrambles data so it cannot be understood if stolen, unless read with a decryption key - it protects data to adhere to DPA.
• How is encryption used in Wi-Fi?


  It is important that all data is encrypted, as signals can easily be picked up by any device.
• How is encryption in ethernet?


  Sensitive data should still be encrypted.
• What is an IP address?


  Internet protocol address - a logical address.
• What is the purpose of IP addresses?


  They identify where a device is on a network so packets can be sent in the right direction, and in the right order.
• Are IP addresses static or dynamic?


  They are dynamic - an available IP address is given to a device when it connects to a router.
• What is IPv4 and IPv6?


  • IPv4 is of 4 denary numbers between 0 and 255, separated by full stops
  • IPv6 is of 8 groups of hex numbers between 0 and FFFF separated by colons
• What is a MAC address?


  A media access control address - a physical address.
• What does the MAC address contain?


  The manufacturer ID and a serial number unique to the device.
• What is the purpose of MAC addresses?


  To identify who a device is on a particular network so data can be sent to it by the router.
• Are MAC addresses static or dynamic?


  They are static - they are given to the network card when the device is made, and cannot be changed.
• What is the format for MAC addresses?


  6 groups of 2 pair hex numbers (separated by colons).
• What are standards?


  Rules about how devices have to work and communicate.
• What is an example of a computing standard?

  The ethernet.