ict chapter 4

• WiFi and Bluetooth use electromagnetic radiation as the carrier of data transmission to offer wireless communication between devices
• WiFi and Bluetooth uses electromagnetic radiation as the carrier of data transmission to offer wireless communication between devices
• The act of changing the channels they use is called spread spectrum frequency hopping
• Bluetooth uses key encryption to create wireless personal area network (WPAN)
• Bluetooth is useful :

  • when transferring data between 2 or more devices which are very close together ( less than 30m distance )
  • when the speed of data transmission is not critical
  • for low bandwidth applications ( eg. sending music files from a mobile phone to a headset )
• Data redundancy is when data is stored on more than one server in case of maintenance or repair, allowing clients to access data at any time.
• 3 common cloud storage systems :

  • public cloud
  • private cloud
  • hybrid cloud
• Public cloud : this is a storage environment where the client and cloud storage provider are different companies
• Private cloud : this is storage provided by a dedicated environment behind a company firewall, client and cloud storage provider are integrated and operate as a single entity
• Hybrid cloud : This is a combination of the 2 previous environments, some data resides in the private cloud and less sensitive/less commercial data can be accessed from a public cloud storage provider
• Advantage of cloud storage :

  • the cloud system offers almost unlimited storage
  • client files stored in the cloud can be accessed at any time from any device, anywhere in the world, as long as internet access is available
  • if a client has a failure of their hard disk or backup device, cloud storage will allow recovery of their data
• Disadvantage of cloud storage :

  • if the client has a slow or unstable internet connection, they could have many problems accessing or downloading their data/files
  • there is a risk of loss of all backup data ( data loss )
  • costs can be high if a large storage capacity or high download/upload data transfer rate is required
• A NIC is needed to allow a device to connect to a network. A NIC turns binary data into an electrical signal that allows access to a network
• Each NIC is given a unique hardwired (or hard-coded) media access control (MAC) address at the manufacturing stage. When installed in a device, the MAC uniquely identifies that device
• Wireless network interface cards (WNICs) are the same as NICs in that they are used to connect devices to the internet or other networks. However, they use wireless connectivity, utilising an antenna to communicate with networks via microwaves.
• The media access control (MAC) address is a number which uniquely identifies a device when it is connected to a network.
• MAC addresses are useful when trying to identify network faults because they never change, which makes it a more reliable method of identifying data senders and data receivers on a network.
• Because the operation of the internet is based on a set of protocols (rules), it is necessary to supply an IP address. Internet protocols define the rules that must be agreed by senders and receivers of data communicating through the internet. An IP address essentially identifies the location of a device on a network.
• Data packets

  Data is moved around networks in the form of data packets
• Sending data

  1. Data is split up into a number of packets

  2. Each packet is transmitted separately
• Packet header contents

  • Sender's IP address
  • Receiver's IP address
  • Sequence/identity number of the packet
  • Packet size
  • Number of data packets that make up the whole message
• Router receiving a packet

  1. Checks the destination IP address against the stored routing table

  2. Determines the packet's next step in the path
• A data packet will pass through a number of routers before it reaches its final destination
• The information in the data packet headers allows the data packets to be reassembled in their correct order, according to the sequence/identity number, by the receiving station
• Hubs

  • Hardware devices that can have a number of other devices connected to them
  • Used primarily to connect devices together to form a local area network (LAN), often in the same building
• Hub operation

  1. Takes a data packet received at one of its ports

  2. Broadcasts it to every device connected to it
• Data packets are delivered to every device on the network

  • Hubs are not very secure because every device will receive every data packet
  • There will be unnecessary traffic on the network, which results in reduced bandwidth
• distances :

  WAN - 100km - 1000k

  MAN - 1km - 100km

  LAN - 10m - 1000m
• advantages of zero login :

  • enhanced security
  • faster and easier way to login to a system
• there are many types of authentication :

  • zero login
  • biometrics
  • physical tokens
  • electronic tokens
  • smart cards
  • magnetic stripes
• disadvantages of zero login :

  • how do users know when they are being monitored
  • how do you know if and when you have been logged out
  • how well protected is it in reality
• advantages of magnetic stripe cards :

  • easy to use
  • it is not expensive technology
  • magnetic cards can be remotely deactivated ( if lost or stolen )
• disadvantages of magnetic stripe cards :

  • less secure than, for example, biometric methods (no encryption is used and the stripe contents can be copied fairly easily)
  • The cards wear out with a lot of use.
  • Magnetic readers often fail to read the cards on first attempt.
• disconnected physical token : where a separate device is used, requiring the user to key in data manually using a keypad

  connected physical token : this type of token transmits the generated one-time password directly to a computer through a USB connection; the user does not need to manually enter data.
• features of anti virus software :

  • They check software or files before they are run or loaded on a computer.
  • Anti-virus software compares a possible virus against a database of known viruses.
  • They carry out heuristic checking – this is the checking of software for types of behaviour that could indicate a possible virus; this is useful if software is infected by a virus not yet on the database.
• Video conferencing


  A communication method that uses both video and sound
• Video conferencing


  • It is a substitute for face-to-face conferences between a number of people, who may be in a different part of the country or live overseas
  • It is carried out in real time and makes use of some form of network
• Basic hardware for video conferencing


  • Webcams
  • Large monitors/television screens
  • Microphones
  • Speakers
• Preparing for a video conference


  1. Agree a time and date for the conference to take place

  2. The delegates in each conference room must log into the video-conference system

  3. The video-conference set-up needs to be checked before the meeting goes live

  4. Webcams need to be placed in the correct position so that all the delegates in the room are within visual contact

  5. Microphones need to be placed centrally so that all of the delegates can speak

  6. It is important for one person to be the main contact in each conference room to make sure each delegate is able to be heard
• In addition to the hardware items, software plays an important role in a successful video conference