Connectivity

Connectivity

1. Home networks

   • Most homes with a home network use it primarily to allow users to share an internet connection.
   • Local area network
     • To create a home network you need to set up a local area network or LAN. This connects all the computers in the house so resources can be shared.
     • Benefits = sharing the internet connection, sharing files, sharing peripherals and internet telephone services.
   • Routers
     • Connecting to the Internet from a home network requires a router. The router connects all the computers to the modem by giving them an internal IP address so that it 'knows' where to send the data.
   • You need a network interface card (NIC) to connect the computers to the network unless you are using Wi-Fi dongles.

2. Network security

   • Importance of security
     • When you connect to your own wireless network you will see all the others within range in a pop up. You can see other people's networks and if it's not secure they will be able to use your Internet connection - at your cost. There are also websites which publish the location of unsecured 'hot spots' so people can get internet access without paying.
   • Ways of securing wireless networks
     • Changing the default admin password on the router
     • Setting up a form of encryption
     • Setting up a Media Access Control address filtering.
     • Turning off the router when not in use
   • Encryption
     • Encryption scrambles data so that only computers with the right key can access it. The most common form of protection for wireless networks is WEP but WPA2 is more secure and becoming more popular.
     • Each device in your network has MAC address. You can specify which addresses can connect to your wireless network. Remember, a firewall or locking a door will not prevent people accessing a non-secure wireless network.

3. Combining technologies

   • Communications technologies in different devices:
     • Phone: 4G, Wi-Fi, Bluetooth and USB port
     • Laptop: Wi-Fi, USB port, firewall port, Bluetooth and Ethernet port
   • Devices working together
     • The mobile phone and the laptop are compatible because they both have USB ports and can communicate via Wi-Fi or Bluetooth. So you can use the camera on the phone to take a picture, transfer it to a memory stick and them and via Ethernet cable.
     • Many devices are converging: performing functions that were originally performed by different devices. If your mobile phone has a camera and an internet connection, you can take and upload photos to a website using just one device. A device that can perform several functions is called a multifunctional device.

4. Bandwidth and latency

   • Bandwidth = measurement of capacity
     • Bandwidth is the number of bits that can go through the network connection in 1 second. It's measured in bits per second.
     • High bandwidth = lots of bits. Low bandwidth = not many bits.
   • Latency = measurement of delay
     • Latency is the time in milliseconds between a bit leaving one device and arriving at the other. It's measured in milliseconds.
     • Low latency = short time. High latency = long time
   • User experience
     • For streaming videos from YouTube you need a high bandwidth network connection, otherwise the video will keep pausing as your computer waits for more bits to arrive. To get quick search results from Google you need a low latency network connection. Information is travelling in both directions so it needs to arrive quickly.
       • The best networks, including those suitable for online gaming, have high bandwidth and low latency. Remember that low bandwidth and high latency are usually bad from a user's point of view.

5. Wi-Fi and mobile broadband

   • The most common ways of connecting to the internet on the move and Wi-Fi hotspots and mobile broadband which relies on the 3G network at present.
   • Wi-Fi
     • Wi-Fi devices need to be within range of a wireless access point or 'hotspot'.
     • BENEFITS = Good range - works up to 60 meters from the hotspot, SPEEDS UP TO 54Mbps and quite widely available.
     • DRAWBACKS = Hackers sometimes set up fake Wi-Fi hotspots putting users' details at risk and you cannot use if you're not in range.
   • Mobile broadband
     • At present, mobile broadband allows devices to connect to the Internet via the same network that 3G mobile phones use. Many mobile phone have the technology to pick up 3G signals built in, whereas other devices such as laptops need a dongle . A mobile phone with 3G capability can also be made into a hotspot.
     • BENEFITS = Greater coverage than Wi-Fi and it's more secure than Wi-Fi as data is encrypted.
     • DRAWBACKS = Have to pay for broadband including roaming charges if you're abroad, downloads limited and lower bandwidth than Wi-Fi.

6. Peer-to-Peer networks

   • A peer-to-peer network is when digital devices communicate wirelessly with each other directly without the need for a transmitter between them. You need to know about the technology that allows peer-to-peer networks to be set up.
     • In the past.....
       • Devices communicated with in each other through a transmitter: a wireless access point when using Wi-Fi and a mobile phone mast when using mobile broadband.
     • Wi-Fi direct
       • The Wi-Fi Alliance has now introduce Wi-Fi direct. This new technology allows devices to connect directly using Wi-Fi without the need for a wireless access point.
       • BENEFITS = Wi-Fi Direct allows users to set up peer-to-peer networks. Wi-Fi Direct also allows the devices to use an access point for normal Wi-Fi use.
     • Bluetooth
       • Another way of establishing a peer-to-peer network is to use Bluetooth.
       • BENEFITS = Allows devices to communicate automatically when within range, can connect up to 8 devices at the same time and low power so doesn't interfere with other devices.