Lesson video

Hi, I'm Allen, computing teacher for the unit, which is KS4 Networks.

In this lesson is one of six and this is all about what networks are.

You will need a pen and paper for this lesson.

As you'll need to write down some answers for some of the tasks.

You can turn off all notifications on any mobile devices.

And remember I need distractions that are nearby.

When you're ready, we can make a start.

Okay, in this lesson, we're going to define what networks are.

We're going to describe the hardware needed to create a network of devices.

I'm going to explain some of the problems and benefits associated with networks too.

So how would you describe a computer network? Somebody says to you, what is a computer network? What would you say to them? You can pause the video and have a think for a second.

We'll put simply, a computer network is two or more devices connected together, so they are able to share resources.

So let's take a look at some networking hardware.

On the left you can see a network interface card or NIC as it's abbreviated to.

And this enables a wired connection to be made between a computer and another network device.

On the right hand side, you have a wireless access point and that connects to a wired network and provides wireless network access to other devices.

On the left-hand side here we have a switch which allows devices to connect to it via an Ethernet cable, and uses packet switching to ensure that the right data gets to the right device.

But on the right-hand side you have a router which is responsible for moving data from one network across to another.

So for instance, from your home network to the internet.

On the left, you can see a modem which converts analogue data to digital signals.

And then that can be transmitted over networks traditionally through telephone cables.

And on the right, you can see a wireless network interface card or wireless NIC.

This performs a similar function to a normal interface card but uses radio signals to connect to the network.

Okay, so it's time for task 1.

On the worksheet, you have a number of devices that we've just previously explained.

You've got to match the right name up to the right device.

And then when you've done that, you can write a definition of what that device is responsible for on that too.

You can pause the video and complete the task.

Okay, how did you get along? Well, the first image is of a router.

Again, that is responsible for moving data from one network to another.

We then had the next graphic down which was a network interface card, which enables a wired connection between a computer and another network device.

The third one down was number 5 which was a modem, converts data from analogue to digital signals to be transmitted generally across telephone cables as we said before.

The next image down was a wireless network network interface card which performs a similar function to a network interface card but uses radio signals to connect to the network.

The second to last one was a wireless access point.

So that connects to a wide network and provides wireless network access.

And the last one is a switch, which enables multiple wide devices to connect to the network.

And as we said before this uses packet switching to make sure that all devices get the correct information.

Okay, time for task 2.

On the worksheet you've been provided with some advantages and disadvantages of some statements about networks.

You've got to have a think about them and decide whether they're an advantage of a network or a disadvantage.

You can pause the video and complete the task.

Okay, well here's as a solution for you we can have a look down the right hand side and see whether there are advantages or disadvantages.

Sharing device such as printers.

Well, that's an advantage, a clear advantage.

So we can have one printer in a room full of people in a classroom, for instance, and you can all have access to that printer instead of requiring one connected to each machine.

Managing networks is complicated, but that is a bit of a disadvantage.

It doesn't require somebody who's trained in network technologies to be able to manage that network and problem solve, should something go wrong.

It's easiest to backup data from a network computer to a remote server.

Well, that's clearly an advantage.

Backing up data is very, very important.

And if networking can obviously assist in this then that's fantastic because then the data is not all in one place.

It can be backed up to somewhere separate.

So if anything has happened in here, for instance and I lost my data in this room, if it was backed up to somewhere externally, then I'd be able to restore that data when the time comes.

Software can be shared across all computers in the network.

Well, again, that's clearly an advantage.

Thinking of a classroom setting.

You all may require a test, a certain piece of software and the fact that they can all be shared on the network for multiple users to use is clearly an advantage.

Hacking of computers becomes much more likely when connected to a network.

Well, this is the disadvantages.

And so if you've got a device connected to the internet and you know, a hacker wants to compromise your machine or run some malicious software on that then that becomes much easier if it's actually connected to the network as opposed to not.

Data can be stored centrally.

This is similar to the kind of software shared across the network.

It's an advantage, if multiple people want access to the same data in an organisation or in a school for instance, then having that data stored centrally means those that require access to it can get access to it.

Networking equipment can be expensive.

Well, that's clearly a disadvantage.

The benefits may outweigh that, but again to have a network installed with a specialist equipment would be expensive.

We've now piracy and illegal copying of data is easier across the network.

Well, that's clearly a disadvantage.

And so having software on a device that is networked allows you to be able to copy that somewhere else.

And again, if that's, you know a piece of software that's licenced then obviously that becomes easier but it's a disadvantage for sure.

And network allows for electronic communications such as email or instant messages.

Great, I think, I don't know where we'd be without email or instant messages now, particularly instant messaging.

So that's clearly an advantage.

Allows us to communicate more easily.

Disadvantage viruses can spread more easily from one computer to another.

Well, yeah, just like the way, you know, viruses spread between humans and network connection is the vehicle that allows viruses to spread from one machine to another.

So clearly by being on a network, then that allows that possibility.

Users can connect with other users in different countries.

While that's a great advantage, despite being on different time zones we can contact people at the other side of the world, pretty much instantaneously.

Similarly with similar kind of benefit users can work on documents collaboratively.

So again, I could be working on a document with somebody in London, for instance, and I'm up here in North Wales, or I could equally be working on a document with somebody in Australia.

It doesn't really matter, the network facilitates that for us.

Files can easily be shared between users.

Excuse me, again, same thing applies, if I'm working on something, I need to share files with someone regardless of where they are as long as we're all network, then that can be done to.

And security of the computers attached to a network is much more complicated.

Well, that is a disadvantage.

If you've just got one, the one machine at home and you're thinking about the security of that machine then that's fairly easy to think about.

You know you can make sure that your software is always up-to-date and you've got a strong password on your machine.

Your route has got a strong password, too.

That's all you really have to think about.

As soon as you start connecting machines together and having different networks connected to each other then the security does become a little bit more complicated.

Okay, so task 3.

What I'd like you to do for this task is think of some examples where computer networks might exist.

And why they might be networked or you know, how they might be networked together.

For what reason? Not necessarily, you know, a computer with a printer for instance, you've got a little bit of a tip in the picture there on the right hand side.

So you might get in, you've got your first one for you.

See if you can think about some networks that exist already and why they might be connected together.

You can pause the video and complete the task.

Okay, how did you get along? Well, this is a potential solution, okay.

So this isn't the exhaustive list of possible networks but it's just some that I've put down to give you an idea of how we might go about these kinds of tasks.

So I had a picture of a traffic light on the original task introduction, if you remember.

So a traffic light system, at a acrossroads, all the traffic lights and network together, so that they can communicate.

and they know when one is on red the other on green and not all on green at same time.

Otherwise that would be a bit of a problem.

Another example would be a point of point of sale machine or tills in a store.

There'll be networked so that they can keep control of stock levels.

So if somebody buys, you know, tin of beans or some milk or bread, whatever, then that is knocked off what the store knows it's got in stock.

And then head office would know how many to send or the store's running out.

And also for accounting purposes for financial data as well.

If you go to a restaurant some of staff may have handheld devices rather than a pen and pad.

They can take your order on a handheld device.

They can put that on a little dock or it'll wirelessly sending information to the kitchen.

And then that food is cooked without the need for going backwards and forwards to a kitchen with a piece of paper.

We've got ATM or cash machines or to teller machines, connected to the central banking network.

So if you put your card in and you withdraw some money out of your account, then that's obviously connected to the bank that you bank with.

And then it knows to update your balance.

And then lastly, I've put down a ticket machine at a train station.

So that will be networked.

It would need to be linked to the timetabling so that it knows what kind of journeys are going to and from where it's specific times of the day and then would allow you to purchase tickets.

And then the train network would know, how many people are expected on that train.

So that's just some examples for you, they're hundreds more and you may have got some different ones.

I'd love you to share what they are, if you have got some different ones.

So, as I said before, it'd be great if you could share your work on Oak National if you've got some networks that I didn't come up with.

If you'd like to please ask your parent or carer to share your work on Instagram, Facebook or Twitter, tagging @OakNational and #LearnwithOak.