Network Notes

COMPUTER NETWORK

Wi-Fi

  • Enables computers and other devices to communicate wirelessly with each other.
  • Wireless transmitter receives information from a network via its connection, converts it into radio waves and then transmits them.
  • Areas where internet can be accessed wirelessly using Wi-Fi are called Access Points or Hotspots.
  • Signal range depends on the type of wireless router and also obstacles in the way of the signal.

Advantages

  • You are not confined to a fixed place to access the network
  • Fewer/no trailing wires to trip over
  • Less wires – less installation costs
     

Disadvantages

  • Danger of hackers reading messages
  • Wireless signals may be weak in certain areas.
  • Recent research shows evidences of health risks

Bluetooth

  • It is a wireless technology used to exchange data over short distances using radio waves
  • Paired devices using Bluetooth pick up one of the 79 channels at random for data transfer
  • Used for short distances, where data transfer speed is not crucial and bandwidth is low.
  • suitable for small files

Applications

  • Connecting a keyboard to a computer
  • Connecting a wireless mouse to a computer
  • Connecting a wireless headset to a computer/smart phone
  • Printing wirelessly from a smart phone
  • Transfering data from a computer to a mobile phone
  • Transferring data from smart phone to a computer

 

Comparinson of WiFi and Bluetooth

FEATURE

Bluetooth

Wi-Fi

Maximum data transfer rate 25 Mbps 250 Mbps
Maximum effective range 30 metres 100 metres
Maximum number of devices connected Up to 7 Depends on the router used
Types of data transmission security Key matching encryption used

WEP: Wireless Equivalent Privacy

WPA: Wi-Fi Protected Access

Setting up a small network

  1. Purchase appropriate hardware and software
  2. Choose an Internet Service Provider (ISP), pay them subscription charges, get a router (often provided by ISP that includes wireless access point).
  3. Connect the router to the telephone line or cable point or satellite link
  4. Connect any cabled device (desktops, printers etc.) to the router using wires between the router ports and the Network Interface Card (NIC) on the device.
  5. Connect wireless devices (laptops, phones etc.) and configure them using their OS network settings
  6. Browser is required on each device to access the internet.

Some essential parts of a network

Access to an Internet Service Provider (ISP) 

  • Supplies the connection to the internet
  • Provides hardware such as Router/Wireless access point.
  • Storage on their server, where you can store your website
  • Email facilities
  • Instant messaging
  • Access to online Shopping
  • Access to news, sport, weather, financial pages etc.

Web Browser Software 

  • Program that allows to view web pages stored on the internet
  • Web browsers interpret the HTML codes in the web page
  • Web browsers allow the user to find information on web pages and websites via: Entering web address (URL), Keyword searches, Hyperlinks and Menus.

Email Software 

  • Software for creating, sending, receiving and organizing electronic mail, or email.
  • Features include: WYSIWYG editors for composing email messages, Anti-spam and anti-phishing security protection, Advanced search capabilities, Rules and filters for more efficiently handling and organizing messages, Email folders.

INTERNET

The largest network in the world, it is formed by huge group of worldwide networks joined together. Each of these networks consists of lots of smaller networks. When you connect to the internet, your computer becomes part of the largest network in the world.

Internet - Advantages

  • Huge amount of information can be accessed almost anywhere
  • Improved communication systems – text messages, emails, instant messaging etc.
  • Voice Over Internet Protocol (VoIP) – enables cheap international phone calls using internet rather than expensive phone service
  • Online shopping (E-commerce)
  • Online banking, bill payments etc.

Internet - Disadvantages

  • Misinformation: presence of many bogus or fake websites. You need to be careful while choosing information and look for only reliable sites.
  • Cyber crime: Hacking, Phishing etc. You need to be careful about revealing personal information such as bank and credit card details.
  • Addiction to games, gambling
  • Paedophiles look for children using the internet

World Wide Web and Internet

WWW is the way of storing and accessing the information over the internet whereas Internet is the infrastructure consisting of all the computers, devices.

INTRANET

Intranet is a private network that is used inside an organisation, makes use of web pages, browsers and other internet technologies.
Intranet provides restricted access to the information compared to the Internet. Parts of an intranet can be made available to anyone in the organization while some part of it consisting sensitive information can be made available to certain people only.
The restriction is achieved usually by means of username and passwords.

INTERNET Vs. INTRANET

Intertnet vs Intranet

 

WLAN - Wireless Local Area Network

  • Computers/Devices are able to communicate wirelessly
  • Uses are able to move around but can still be connected to the network/Internet.

WLAN - Advantages

  • Cheaper than wired LAN and less cabling is needed
  • Expansion of the network is easier – more devices such as printers scanners can be linked easily.
  • Users can work anywhere in the building where the wireless signal is available

WLAN - Disadvantages

  • Not suitable in areas where the wireless signal is too weak
  • Security issues as the radio signals may be intercepted by hackers
  • Wireless signals are not reliable as wired cables
  • Data transfer speed is lower than cabled network
  • Interference from other electrical and electronic equipment used in the same building may disrupt the wireless signal

 internet via smartphoe

 

Internet via tablet

 

 

 

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