Networks

• firewall


  A hardware device or piece of software that monitors packets going to and from a network
• protocol layering

  splitting the complicated process of networking into individual functions
• Advantages of client-server

  • data stored in one location
  • only one point of failure
  • only one location to backup
  • data and recourses can be shared between clients
• Disadvantages of client-server

  expensive to set up and maintain

  functionality depends on server, if the central point fails the whole system goes down
• Advantages peer-peer

  • cheaper and easier to maintain
  • not dependant on central server
  • allows users to share recourses
• Disadvantages of peer-peer

  • backups need to be performed separately
  • impossible to trace the location of files so difficult to locate recourses
• Explain why protocols are important on a network

  Allows network to communicate by ensuring all devices follow the same

  rules/standards so they interpret data/signals in the same way
• State the name of the four layers of the TCP/IP stack.

  1. Application Layer
  2. Transport Layer
  3. Internet Layer
  4. Link Layer
• Describe what is meant by the term 'WAN'

  Wide Area Network

  Collection of connected devices over a large geographical area often using 3rd party communications channels
• With regards to network protocols define what is meant by layer

  a division of network function
• benefits of LAN

  • can work collaboratively on same files
  • share hardware recourse
  • access files from any computer on network
  • software is deployed and updated from central point
• how long are IP addresses and what are they written in?

  4 bytes deanery
• where is an IP address configured?

  software
• What are IP addresses used for?

  routing across WAN
• how long are MAC addresses and what are they written in?

  6 bytes, HEX
• Where is a MAC address configured?

  hardware
• IP vs MAC

  IP can be changed and are allocated as needed, MAC cannot be changed
• advantage of using layers to construct network protocols

  • It is self-contained
  • Allows different developers to concentrate on one aspect of the network
  • Can be taken out and edited without affecting other layers
• WAN vs LAN

  • WAN over a large geographical area, LAN over a small geographical area.
  • WAN uses external hardware, LAN has its own infrastructure
• Name the system which matches URLs to IP addresses on the web.

  Domain Name Server
• Identify three tasks carried out by a router.

  1. Receive packets
  2. Transmits packets
  3. Assign IP addresses to nodes/devices
  4. Converts packets from one protocol to another.
• Which device connects a local area network to the internet?

  router
• Explain what is meant by circuit switching

  Sending data over a WAN. The nodes of each network establish a communications channel where all data will follow this path during data transfer
• For client-server what does the server control?

  server controls access and security to one shared file store
• on client-server where is data stored?

  one shared file
• What does the DNS do?

  maps a domain name in a URL to an IP address
• What is packet switching?


  A method of transmitting data in which it is broken down into small packets and sent separately over a network.
• How does packet switching work?

  • TCP splits data in smaller packets
  • Each packet is given a number and an address and takes it's own route across the network
  • Packets are received by the host server, checked and request for packets is resent if necessary
  • Packets are assembled back in correct order and the request is processed
• protocol


  set of rules for how devices communicate
• proxy


  a computer application that accesses data on different computer systems/networks
• TCP

  Transmission control protocol

  provides an error free transmission between two routers
• IP

  Internet protocol

  routes packets across a WAN
• An IP routes packets across a what?

  WAN
• Describe what is meant by the term 'client-server'

  Client devices connected to a server, that provides access to a recourse/service
• Explain purpose of network switch

  • Joins devices together on a LAN
  • Receives packets
  • Recipient’s address is given in packet header/it uses the mac address
  • Sends packets
• Explain what happens to the link layer of the TCP/IP

  • Receives data from internet layer to send
  • MAC addresses are added to the packet
  • Passes and receives data across wireless network
• Explain what happens at the application layer

  • Protocol to be used is decided based on the application
  • Adds encryption
  • Passes on to transport layer to send
  • Gets data from transport layer when receiving
  • Removes headers or other non-viewable data
  • Decrypts message
• server

  A device which provides a central point of access/control