Communication Technologies

Communication technologies are systems that allow us to transmit data between devices, such as over a local area network or the internet.

These are essential in the modern world in both our business and personal lives – be it messaging your friend across the street, or working with a colleague based in another country.

This lesson we’ll learn about:

  1. Setting up an ad-hoc network
  2. Security issues with open networks
  3. Performance issues with ad-hoc networks
  4. Issues affecting network availability

Media Attachments: Presentation Video

1. Setting Up an Ad-Hoc Network

Setting Up an Ad-Hoc Network

An ad-hoc network is where two devices can directly communicate with each other, instead of through a medium like a router or wireless access point. Personal Area Networks (where multiple devices connect around a single individual) commonly are set up as an ad-hoc network.

There are many ways to create an ad-hoc network, some of which are very complex, but there are also some simpler methods that you’ve probably used before. The most common of these is Tethering.

Tethering is where a device used to create a personal hotspot that other devices can connect to and make use of its internet connection. This most commonly would be connecting a laptop to a smartphone to make use of its mobile broadband connection. This is commonly done with wireless methods like Wi-Fi or Bluetooth, however, it can also use a wired USB connection.

  • Easier to connect devices together so setting up the network is quicker and simpler.
  • Less expensive as the lack of a central access point saves on the cost of this device.
  • Less speed as ad-hoc modes usually only support slower transfer speeds.
  • Less secure as ad-hoc devices have limited control of connections so it’s easier for an attacker to connect.

Further Thought

There’s also a method of directly connecting to another PC on your own PC using an ad-hoc network. Try and look up how this is done and see how complicated it is compared to creating a hotspot using your phone.

2. Security Issues with Open Networks

Security Issues with Open Networks

Open Wi-Fi is a wi-fi hotspot that that doesn’t require a password to access. This means that they don’t have encryption and so data sent over them is insecure. We commonly find these in places like restaurants, cafés and hotels.

As these open wi-fi networks can be connected to without a password and don’t use encryption on the data transmitted over the network you must be aware that anybody within signal range can connect to the network also and could steal your data.

These other users could use special tools so that any information sent over the open network could be intercepted (for example, your bank account details, passwords, etc.). In fact, on an unencrypted wireless network, its possible for an attacker to steal data being transmitted without even connecting to the wireless network themselves.

This is why your device often provides a warning when connecting to an open network. You should never transmit any private data when connected to an open network unless you are using an encryption technology like a VPN (Virtual Private Network).

Further Thought

We mention VPNs can be used to make transmitting private data on an open network secure. Research exactly what a VPN is.

3. Performance Issues with Ad-Hoc Networks

Network Services and Resources

A major limitation of ad-hoc networks are the performance issues that these networks suffer from. There are a number of performance issues, most notably:

  • Maximum Speed – ad-hoc networks cannot transfer data as fast as networks in infrastructure mode as they have a smaller maximum data transfer speed.
  • Maximum Range – wireless routers have higher powered antennas and so can provide much greater ranges than wireless connections directly between devices. Other methods of ad-hoc networks like Bluetooth and USB cables have very short ranges too. Further, when in ad-hoc mode, operating systems usually hide the signal strength indicator.
  • Interference – ad-hoc networks produce a lot more interference when many devices are connecting as each has its own connection with devices often moving around and crossing signals. This can reduce range, lead to dropped connections and reduce speed.

Further Thought

With these performance issues in mind, why do we use ad-hoc mode at all? Think about different situations it would be used in and why ad-hoc mode is preferable.

4. Issues Affecting Network Availability

Network Monitoring Tools

Below we will go into different issues that can affect the performance and availability of networks:

  • Location of the network – is it city or rural?
    • City locations tend to have excellent network coverage as there are lots of people, so telecom companies will have a big market to compete in and so will invest heavily in these areas.
    • Rural locations are sparsely populated so less money will be invested for proper coverage. This means less choice of providers, longer distances from exchanges/cell phone towers and therefore slower connections.
  • Location of the network – developed or developing country?
    • Developed countries will likely provide excellent network coverage as money will be appropriately put into developing these networks.
    • Developing country often won’t have enough money devoted to its countries network infrastructure to provide coverage across the country and modern broadband speeds.
  • Available infrastructure
    • This can tie in with the above mentioned, as rural areas and developing countries will have infrastructure unable to support fast speeds.
    • For example, if you want to get fibre to the premises connections in Britain, you’ll usually need to live in a city or town.
  • Mobile network coverage
    • Some locations will not have cell phone towers located within a close enough distance to provide access to a 4G connection. You may not have a mobile broadband connection at all.
    • Generally speaking 4G broadband covers around 90% of the UK landmass, but this can vary a bit depending on the provider.
  • Blackspots
    • Geographical features like mountains, valleys or hills will disrupt wireless signals as the signals can’t pass through solid stone.
    • This can be similar in big cities with buildings made of thick concrete, where signals will have an equally tough time getting through.

Further Thought

Think about some of the implications this would have on businesses that want to operate around the world. What is the impact of poor network coverage in developing countries?

Lesson Summary

So to summarise what we’ve learnt in this lesson:

  • The ad-hoc mode of a network allows two devices to directly communicate with each other.
  • They are cheaper and easier to set up but are less secure and offer poorer performance.
  • Personal hotspots (tethering) allow others to piggyback off your phone and use its Internet connection.
  • Open Wi-Fi are unencrypted networks from which you can connect to the Internet.
  • Any information sent over an open network is at risk of being intercepted and viewed.
  • Ad-hoc networks have a limited maximum speed that is low, have a shorter range and are more susceptible to interference.
  • If connecting to an ad-hoc network, you will need to be as close to the source as possible else your signal strength will be poor and unstable.
  • Network availability has many issues depending on location:
    • Rural places will have limited coverage due to sparse population and poor infrastructure.
    • Developing countries won’t have proper funding to develop infrastructure and support fast speeds.
    • Available infrastructure and mobile network coverage may mean fast connections are not possible.
    • Mountains, valleys, hills and concrete buildings can cause blackspots where signal strength is poor or non-existent.