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

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. Some examples of this include:

  • Connecting your smartwatch to your phone.
  • Temporarily connecting two laptops to transfer files between them.
  • Connecting your smartphone to your laptop to use its mobile broadband connection (known as tethering).

These ad-hoc networks are commonly set up with wireless methods like Wi-Fi or Bluetooth, however, it can also use a wired USB connection.

There are some clear benefits to setting up an ad-hoc network in these examples. However, there are some clear disadvantages to ad-hoc networks that make them not suitable for most situations.

Advantages

  • It is easier to connect devices together so setting up the network is quicker and simpler. This is very important in situations where the users are not very IT literate.
  • It is less expensive as the lack of a central access point such as a home router. This saves us the money of purchasing this device. It also means we don’t need to carry an additional device around with us.

Disadvantages

  • Ad-hoc networks are slower than traditional networks. This is because devices using the ad-hoc networking mode usually only support slower transfer speeds.
  • They are usually less secure due to commonly using wireless connections (which are less secure than wired ones) and there is no central device for managing the security of the network.

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.

2. Security Issues with Open Networks

Open networks are a wireless network 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.

Encryption is where your data is jumbled up to make it unreadable should someone manage to intercept your data. We’ll learn more about encryption later in the course.

We commonly find open networks in places like restaurants, cafés and hotels, because they want customers to be able to easily connect to the internet, without having to enter a password.

Wi-Fi networks broadcast data out, so any computer in range connected to the network will receive that data. It’s just that computers will normally ignore the data not addressed to them.

However, a malicious user could use special tools, such as a “packet sniffer” to read any data sent over the network even if it isn’t addressed to them. This might be your passwords or your bank details for example.

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

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. The speeds can also be affected by the increased interference.
  • 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 interference can increase the corruption of the data being transferred, which means this data will need to be re-sent. 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 connections, most notably your connection to the internet are not equal across the entire world. There are many issues that will affect the availability and performance of both mobile broadband and traditional broadband for end users.

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

Location of the Network

Cities are likely to have excellent network coverage as, due to the higher population levels, telecom providers will invest far more in these areas.

This includes having far more phone masts offering mobile broadband connectivity as well as providing access to superfast broadband, including FTTP (Fibre to the Premises).

This will mean that for those in rural areas you may not have fast fibre-optic broadband in your area and 4G mobile broadband, and even if you do, the speeds will be significantly poorer. In the case of mobile broadband, it’ll also be more like that you will get dropouts where your internet stops working.

This is even more true of the difference between developed and developing countries. 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.

The image below shows the difference between 4G availability in Zimbabwe and the UK. Red areas indicate the availability of 4G broadband.

Available Infrastructure

We’ve already mentioned in the previous section about the difference in infrastructure between cities and rural areas, as well as between developed countries and developing ones.

This includes the availability of cell phone towers providing mobile broadband connections as well as having the required infrastructure for fibre optic broadband to be made available.

For example, within the UK, if you want to have an FTTP connection in your home, you will likely need to live in a city or town as these are often the only places that will have the infrastructure to offer this.

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. We saw this in the images previously shown in this lesson.

The availability of good mobile network coverage isn’t just how far you are from a cell phone tower though, it is also affected by blackspots that can be caused by geographical features.

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.

We could find that our mobile broadband connections will drop out while travelling from things like passing through a tunnel, which would stop anything we’re downloading and could cause us to lose something we’ve been working on.

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.
  • Tethering allows you to piggyback off your phone and use its Internet connection.
  • Open networks are unencrypted Wi-Fi 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.