chapter 5

Cards (39)

  • Devices
    Need to connect to a network and abide by protocols
  • IP address
    Identifies devices on a network, can be assigned by an administrator or DHCP, not fixed and depend on the network
  • Types of IP addresses
    • IPv4 (8 numbers separated by dots, e.g. 192.168.1.1)
    • IPv6 (8 groups of hexadecimals separated by colons, e.g. 2001:0268:0000:0042:0000:8u2e:0370:7334)
  • IPv6 was developed because the number of devices is growing faster than the number of physical users
  • MAC address
    A universally unique identifier made up of 6 pairs of numbers/letters, specific to the network interface card (NIC)
  • Uses of MAC addresses
    • Identifying devices on a network
    • Tracking devices on a network
    • Changing device's access to a network
    • Adjusting dynamic/static IP addresses
  • Each time a device connects to a network, it is identified by DHCP (usually using its MAC) and given the same IP address as before
  • Device names are not the best way to identify devices on a network as several devices can have the same name
  • Components of wired and wireless networks
    • Cables (Cat5, Cat6, optical fibers)
    • Wireless access point (WAP)
    • Gateway
    • Router
    • Switch
    • Booster
    • Server
  • Cables

    Used to connect devices in a wired network, speed measured in Mbit/s or Gbit/s
  • Wireless access point (WAP)

    Connects devices with WiFi connectivity to a wired network wirelessly, built into routers and boosters
  • Gateway
    Connects LAN to WAN
  • Router
    Stores all the connected device's IP addresses and forwards network traffic using the fastest route
  • Switch
    Has many ports to connect devices with wires
  • Booster
    Amplifies a network signal to cover larger distances
  • Server
    A computer that shares its resources with connected devices, called clients
  • Types of servers
    • Authentication server
    • Print server
    • File server
    • Application server
    • Web server
  • Authentication server
    Checks usernames and passwords when a user logs in, provides an electronic certificate to access resources
  • Print server
    Manages multiple printers, deals with print requests from client computers and adds jobs to a queue
  • File server

    Allows users to access shared and private storage
  • Application server
    Provides clients with access to applications that can be run directly from the server
  • Web server
    Processes requests for data made via HTTP, all the content stored on web servers is the World Wide Web
  • Aspects needed to connect to and use the internet
    • Internet service provider
    • Web browser
    • Search engine
    • Filter software
  • Internet service provider

    Grants access to telecommunications infrastructure
  • Web browser
    Takes requests and guarantees access to web servers
  • Search engine
    Allows users to enter keywords which are compared with web pages stored in a database to provide the most relevant results
  • Filter software

    Allows administrators to control users from accessing inappropriate/risky content by filtering web pages through their URL (web address)
  • Types of LAN/home networks
    • Peer-to-peer network
    • Client-server network
  • Peer-to-peer network

    • Devices are connected to each other and share resources without a server
    • Shared file and storage
    • Shared peripherals
    • Easier communication
    • More flexibility
    • Better media usage
    • Shared access to the internet
  • Client-server network
    • All devices are connected to one server
    • Roaming profiles - log into your account from any device
    • Administrator control over user access rights
    • Centralised administration - entire networks easily moderated and kept safe
    • Centralised backup - no hassle for individual users, backup is automated
    • Shared software
    • Shared storage and file access - file permissions can be set, amount of storage available to others
  • Techniques for securing data on networks
    • Logins and passwords
    • Firewalls
    • Encryption (Caesar cipher, symmetric key, public key)
    • Wireless encryption protocols (WEP, WPA)
    • Virtual private networks (VPNs)
  • Logins and passwords
    Users can only access resources with the correct login details, passwords are used to authenticate a user to a network
  • Firewalls
    Found in gateways, control what enters the network or LAN
  • Encryption
    The process of encoding, scrambling and jumbling data so unauthorised users can't understand it
  • Caesar cipher
    All data is shifted by a certain number of units to the left, the number of units is the key
  • Symmetric key encryption
    Uses the same key to encrypt and decrypt
  • Public key encryption
    Uses two mathematically related keys, one public key to encrypt and one private key to decrypt
  • Wireless encryption protocols
    WEP - all data sent out of a network is encrypted using the same key
    WPA - every single device has a unique key on the network, every data packet sent out is encrypted with a unique key
  • Virtual private network (VPN)

    Allows you to access LANs from remote locations, used for secure payments, staying away from tracking, accessing work network from home, accessing geographically locked content