Discovering computer networks: hands on in the Open Networking Lab
Discovering computer networks: hands on in the Open Networking Lab

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Discovering computer networks: hands on in the Open Networking Lab

1.1 Devices on a home network

In this part you will look at some of the devices in a typical home network. There are three short videos to watch and some activities. When you have completed this part you should be able to identify typical home network devices and the connections between them. In particular you should be able to identify a home gateway and understand some of its functions and connections.

Watch the video below, which is about 2 minutes long. It explains what we mean when we talk about a home network.

Devices on a home network

Download this video clip.Video player: 01_devices_on_a_home_network.mp4
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I’ve just been sending a few emails. One to my friend in Portugal, one to my sister who lives about four miles away, and one to husband – he’s working upstairs in the study, today it’s my turn for the kitchen table – but we just needed to exchange a few diary dates. I’ve also paid a few bills online, I’ve booked an airline ticket and I’ve been looking up some information on the internet.

You know, I’ve been using this technology for years now, but I’m still in awe of the way it all works, and I wonder whether you are too? The way our emails get to the right destination, the way we can access information from almost anywhere and the way all our devices will talk to each other. Somehow we take it all for granted, don’t we?

In this house, we’ve got what I think is probably a typical home network setup. There’s a device that I’m going to call the home gateway now that’s connect by cable into our telephone socket. It’s this device that gives us access to the internet, so ‘gateway’ is a good name for it. But quite often it’s also referred to as a home router. My husband and I have both got laptops. We can connect them directly into the home router, but more often than not we connect them wirelessly. We’ve got a wireless printer. We’ve both got smartphones; we’ve both got tablets. And all these devices can talk to each other from more or less anywhere within the house, though we do have a few dead spots.

This collection of interconnected computing devices in a fairly small geographical area is known as a local area network, usually abbreviated as LAN.

In this session we’re going to take a closer look at that device that is at the heart of the home LAN: the home gateway, or home router as it’s sometimes called.

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Activity 1 Think about

5 minutes

  • List all the devices that are connected to your home network.

  • Identify whether they use a wired or a wireless connection – or both.


Did you remember to include devices like a games console, Kindle and smart TV?

Watch the video below, which is about 4 minutes long. This video looks at the network connections in a laptop and a home gateway.

A closer look at network connections

Download this video clip.Video player: 02_a_closer_look_at_network_connections.mp4
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In this video I’m going to take a closer look at my own laptop and gateway – particularly those parts that are associated with the connections between the two.

I’ll start with my laptop. I’ve turned it round so you can see the connections at the back. I’ve got quite a few things plugged in here. Computers and most laptops provide what is known as an Ethernet port. This is for a direct wired connection between the computer and the home gateway. You can see my Ethernet port here. Ethernet is the computer networking technology most used in local area networks. As well as providing the physical system for connecting together a number of devices to form a local area network, Ethernet also controls the way information is passed between devices.

OK. Let’s have a look at this device that I’m calling my home gateway. You’ll often hear it called a router as well but actually it does so much more than routing, which is why I’ve chosen to call it a home gateway. Home gateways come in a variety of form factors. This is a picture of mine. It’s pretty old now – probably four or five years – but a similar model is still available to buy. Nevertheless all models will have some common features. I’ll run through some on mine.

Some models have internal antennas, but mine has two external ones, one set to the 5 GHz band and the other to the 2.4 GHz band. Mine has a set of status lights that indicate its current operating state. A steady light on this one indicates it has an internet connection. This one indicates that it has a functioning ADSL connection. ADSL stands for asymmetric digital subscriber line. It’s a type of broadband communications technology used for connecting to the internet through the copper cables of the telephone network. This is the power indicator. And this one shows whether or not there is a wired Ethernet connection. You’ll see it’s unlit on mine at present as I’m not using any Ethernet connection. This one, however, is lit. It shows there’s a wireless connection.

This set of lights here indicate the volume of activity over the connection. There’s not much activity on my computer at the moment, otherwise you might have seen these lights going up to the full range.

Now I’ll show you the back of my home gateway. I’ve removed all the connecting wires because it just makes it easier to see. So I’m not connected to anything at the moment but if I was this is where the power supply would be connected.

There’s a little dimple here with the word ‘reset’ next to it. If I needed to reset the router to its default settings I’d just have to stick the point of a pen or something like that into that little dimple.

These four connections here are known as Ethernet ports, sometimes called RJ45 ports. These are where I can plug in connections with my external devices such as a desktop computer.

Here at the bottom is the ADSL connection. I talked about ADSL a few moments ago. So this connects to my telephone socket.

Finally, if I look on the base of the device, there’s a label that gives me some more information about it. Do you see that mine identifies itself as a ‘wireless modem router’? Earlier on I said that the device had multi functions and there are some clues here about what these functions are.

The ‘wireless’ part tells you that it’s acting as a wireless access point, the ‘router’ part tells you that it has a routing capability and the ‘modem’ part indicates that it also incorporates a modem (which is short for modulator/demodulator). This converts the signals that arrive through the phone network into signals that can be understood by a computer.

As well as the make and model number of the device there is a set of four bar codes with letters and numbers below them all of which provide information for setting up and connecting to other devices. You’ll learn more about these later but for now, just be aware that most home gateways have some sort of label like this.

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Activity 2 Think about

5 minutes

  • If you can, have a look at your own home gateway. Try to identify some of the common features that were discussed in the video. Go online and search for images of home gateways. (Hint: use ‘home router’ as your search term.) Again, try to identify some of the common features that were discussed in the video.

  • The home gateway images I found online showed many different form factors. Most of them had external antennae – some as many as four. I found a number of images showing the Ethernet and ADSL ports at the back.

  • Go online and search for images of home gateway labels. (Hint: use ‘home router label’ as your search term.) What are the most common features that you saw?

  • Most of the home gateway label images I found showed a set of bar codes, one or more of which had the word MAC by one of them; about half of them showed the SSID.

Watch the video below, which is about 1 minute long. It shows how drawing a diagram of a network helps to visualise how the different network devices are connected together.

Network diagram

Download this video clip.Video player: 03_network_diagram.mp4
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So I’ve shown you some of the components of my own home network and in particular my home gateway. As well as my laptop, the other components I identified as being part of the network are my smartphone and my tablet. I also have a wireless printer. So to finish this session I’m going to create a quick sketch to show how all the components are connected together.

I’ll start with my home gateway. This is connected via the ADSL socket to my telephone socket. My home gateway also acts as a wireless access point and I’m indicating the wireless signals by these curved lines. This is quite a common method of indicating a wireless communication but you’ll come across other ways too.

Here are the other devices I identified: my phone, my tablet and the wireless printer, all with wireless connections to the network. There’s my laptop – again with a wireless connection – and my desktop computer with its wired Ethernet connection to my home gateway.

Your own home network may be different to this. For example your printer may have a physical wired connection to your computer and you might have many more devices than me.

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Activity 3 Try it out

5 minutes

Draw a diagram of your own home network.


Your network diagram probably showed more wireless connections than wired connections.


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