3.5 Fundamentals of Computer Networks

• WAN vs. LAN

  • a WAN is spread across a wider geographical area whereas LANS covers a smaller geographical location
  • Speed of data transmission across a LAN is likely to be faster as it carries less traffic
  • LANS may not need data encryption as they are typically private
• Network Layers

  Application Layer

  • this is where he network applications operate
  • Protocol E.G: HTTPs, FTP, IMAP, SMTP

  Transport Layer

  • sets up the communication between the two hosts and they agree settings such as language and size of packets.
  • Protocol E.G: TCP, UDP
• Network Layers

  Network/Internet Layer

  • addresses and packages data for transmission. Routes the packets across the Network
  • E.G: IP

  Link Layer

  • network hardware located here. OS drivers also sit here.
  • E.G: Ethernet/Wifi
• Network Protocols

  set of rules used by devices for communication across a network
• HTTPS

  Hyper-text transfer protocol (secure), used by web browsers to access websites
• FTP


  File transfer protocol, used to move files between a network
• IMAP

  Internet message access protocol, similar to POP but only deleted when you choose to do so
• SMTP

  Simple mail transfer protocol, used to send emails between servers
• TCP

  Transmission control protocol/internet protocol, splits data into packets and then reassembles into correct order (checks for errors)
• UDP

  User Datagram Protocol, splits data into packets and then reassembles into correct order, sending them for fast transmission across the network (no error checking)
• IP

  Internet Protocol, responsible for packet switching and routes packets across networks
• Ethernet/Wifi

  Establish an active connection between a device and a network (using an NIC)
• BUS Topology


  All the devices connect to ONE main cable, which has terminators at the end (to stop data from going back across the cable)
• Network


  A group of interconnected devices that can communicate with each other
• PAN (Personal Area Network)


  A network that connects devices within a personal space, like a room or a person's body
• LAN (Local Area Network)


  A network that connects devices within a small geographic area, like a home or office
• STAR Topology

  All the devices are connected to a central switch or server that controls the network
• Star Topology Advantages

  • If one device or cable fails, the rest of the network will not be affected.
  • Easier and simpler to add to more devices
  • Limited or no data collisions as devices have independent connections
• Star Topology Disadvantages

  • If wired, the device requires separate cable/wire so can be expensive with many devices
  • If the main server/switch fails then the entire network will fail
  • Additional cabling is required for every device
• Bus Topology Advantages

  • Easier to connect the nodes/devices to each other
  • Less cabling required so its cheaper to install
• Bus Topology Disadvantages

  • If the main cable fails/is damaged, the whole network fails
  • There are more data collisions on this network due to following similar routes
• Computer Network

  a collection of computers together
• Wireless vs Non-Wireless


  Wired

  • Connection speeds typically faster and higher bandwith
  • typically better security
  • Cables can be hazardous
  • not all devices can connect via cable
  • can be expensive to set up

  Wireless

  • lower setup costs
  • easy to connect a new device
  • Users can connect to the network as long as they are within range
  • connected speeds can be slower
  • can be subjected to interference from walls, nearby devices etc
  • connections not as stable
• What is the main advantage of using an interpreter?


  Interpreters are more effective for debugging individual errors.
• What is the function of an Integrated Development Environment (IDE)?

  An IDE provides tools and features to aid program and software development.
• What are the main features of an IDE?

  1. Code editors
  2. Debugging tools
  3. Run Time Environment
  4. Built-in translators
• What is a Wireless Access Point (WAP)?


  A WAP creates a wireless LAN for devices to connect to.
• What is the role of a router in a network?

  A router transmits data between multiple networks.
• What does a switch do in a network?

  A switch connects devices on a LAN and transmits data to the correct MAC address.
• What is a Network Interface Controller/Card (NIC)?


  A NIC is an internal component that allows a device to connect to a network.

  
• What is twisted pair cabling primarily used for?

  Twisted pair cabling is mainly used to physically connect devices on a LAN.
• What is coaxial cabling made of?

  Coaxial cabling is made of a single copper wire surrounded by insulation and shielding.
• What is the purpose of fibre optic cabling?

  Fibre optic cabling refracts light to transmit data over long distances.
• What are the advantages and disadvantages of wired vs wireless networks?

  Wired:

  • More reliable, faster, and stable
  • Less prone to hacking

  
  

  Wireless:

  • Easier to connect more devices
  • More portable and cost-effective
• What are the advantages of computer networks?

  • Sharing of hardware and data
  • Monitoring users
  • Centralized backup
  • Remote access to data
• What are the disadvantages of computer networks?

  • Prone to hacking
  • Slower during heavy traffic
  • Increased installation and maintenance costs
  • Reliance on server
• What are the four main types of network security?

  1. Firewalls
  2. Authentication
  3. MAC Address Filtering
  4. Encryption
• What is the definition of a computer network?

  A computer network is a collection of computers connected together for sharing resources and data.
• What are the four layers of network functionality?

  1. Application layer
  2. Transport layer
  3. Internet layer
  4. Link layer
• What is the function of the transport layer in a network?

  The transport layer sets up communication between two hosts and agrees on settings like language and packet size.