Lesson video

Hi, I'm Allen, your computing teacher of this unit.

This is key stage for networks.

This is lesson two, and this is called basic networks.

You will need a pen and paper for this lesson, as you'll need to write down some of the answers for some of the tasks.

Turn off all notifications that are on any mobile devices, and remove any distractions that are nearby.

You can pause the video until you settled, and when you're ready, we can make a start.

Okay, in this lesson we'll explain, how devices can be connected to a network, whether that's wired or wireless.

We'll define Mac addresses, and there use networks.

And we'll explain the importance of networking, in mobile computing.

Okay, I'm going to start you off straight away with a task.

This is task one, and this is called different types of networks.

On the worksheet provided, you've got some boxes available to write in the kinds of networks that you've used today, in the last week, or in the last month.

So have a think about those, pause the video, and complete the task.

Okay.

How did you get along with that? Well, here's some of mine, they're going to be different for all of us, I suppose.

But today I've used my mobile phone network, to send and receive message.

I've used my raspberry pi, on my home network, to do some work.

And I'm using this laptop right now, that's to record this lesson for you.

This week, I suppose, in addition to the ones I've used today, I've used my home networks to have video calls with colleagues, and I've also used that same network, to stream mindfulness content, using Headspace.

And in addition to the ones I've used this week, I've also used the banking network, cash machine to withdraw money, and also use online shopping, for instance, to buy non-essential items that are not available in the shops, during lockdown.

So they are mine, you probably have some different ones, but it gives you an idea, of the different types of networks, that we use every day, often without really thinking about it.

So let's have a think about this for a second, the need for uniqueness.

okay.

So how do we make sure that a letter if we're posting a letter to someone, gets to the correct recipient.

You could pause the video for a second, and have a think about it.

Well, for a start, we make sure that it's got the correct house number or name, and it's got the post code on the envelope or package.

This combination of house number and postcode, ensures that we've got what's called a unique identifier.

How many houses are in the UK? Well, there's almost 28 million houses in the UK.

So that's a lot of unique identifiers.

How many network devices do you think that are in the UK? Do you think there's one for every house? Do you think there's less than one for every house? Or do you think there's more network devices, than there are houses? My guess is the probably more network devices that are in our houses.

You've got more than one person living in a house, and they've each got a mobile phone for instance, then obviously across the country, that's going to be a lot of devices.

So how do we ensure we have enough unique addresses, for all those devices? Because networking works exactly the same way, as we would for the postal system.

Every device needs to have a unique identifier for itself on a network.

Well, the way this is overcome, is using something called Mac addresses.

And Mac stands for Media Access Control.

Unique addresses are assigned to every single network device, individually.

And you can see on the right hand side, the, there's an example of a Mac address, for a Android mobile phone.

Some Android mobile phone, there's a wifi, adapt to that enables the phones to connect to a wifi network, and there's also Bluetooth hardware, on the device that allows you to connect to other devices using Bluetooth technology.

And each one of those will have a separate Mac address.

So not just one for the device, but one for every single piece of networking hardware.

So that's a really important point.

You can see here, there's one for a Linux laptop.

So the Mac address there you can see one for the wired hardware on the, on the Linux laptop, for connecting to a network, and you can see a wireless Mac address for connecting to a wireless network.

So again, two separate pieces of physical hardware, within those devices, and they will each have a separate Mac address.

So Mac addresses, they're 12 digits long.

The hexadecimal ranging from note to F.

So I'll give you a little bit of task in a second.

They're written in pairs.

So you can see her as an example got zero zero one, one, two, two AABB, FF and so on.

And each pair can be between not naught and FF.

So you can pause the video now and tell me what's the decimal equivalent.

You've got space on the worksheet to write your answers pause the video and complete the task.

Okay.

So hopefully you've realised that we can have between naught and two, five five in hexadecimal between not, naught and FF.

So that makes 256 separate values for every single path.

So with six pairs for a Mac address then, what's the total number of unique Mac addresses available to us? You can pause the video and write this on your worksheet.

Okay.

So it's again.

Okay.

So the answer to this question, if we have six pairs and each pair has 256 possibilities, then we have 256 the power of six, which gives us this number on the screen which is over 281 trillion separate unique addresses.

That's a huge number.

So hopefully that will keep us going for a while.

So there's another thing to think about with so many different companies making network interface cards.

How do we make sure that one manufacturer's interface card can communicate with another? Well, hopefully you've done something previously in other lessons talking about network protocols.

So they're set up by Tripoli, which sounds a bit of the Institute of electrical and electronic engineers.

And this was formed in 1963.

It produces standardisation documents for nearly all technical advances.

And these include things like Ethan networking and wireless networking.

Okay.

So this is task three and this is wired and wireless networks strengths and weaknesses on the worksheet.

You've got some space to write down some advantages and disadvantages of wired and wireless networks through some tips on there for you some things to think about such as suitability cost to instal and things like that.

So you can pause the video and complete the task.

Okay.

So let's take a look at some of the solutions for wired and wireless network strengths and weaknesses or advantages and disadvantages depending how you've worded them.

So wired.

Well, we've got faster transmission speeds as the data travels through physical cables instead of through the air.

And as a result of that, that's less prone to interference.

And it's also harder for that data to be intercepted along the way.

Some disadvantages are weakness.

Well with lots of cable, it's quite expensive.

And, and okay, along with that if you're in an office building or a building that sponsor a large area then getting cable to some of those locations in those buildings can be quite tricky.

It's also not suitable for mobile devices for obvious reasons.

Okay? So let's take a look at wireless strengths and weaknesses or advantages and disadvantages.

Well, it's easy to connect more devices if you've got a wireless access point and you knew that you know the password for that SSI ID or for that network then you can join that fairly easily.

And it uses less equipment and switches than a wired network.

As a result, it's quicker to instal and you only need one access point for an office, as multiple devices can connect to that wireless access point.

Okay.

So let's take a look at the weaknesses or disadvantages of wireless networks.

Radio waves can be intercepted quite easily.

Okay.

So when you're putting that might choose to do some harm by trying to intercept out data than being on a wireless network makes that that little bit easier and radio waves can be affected by interference.

So if you've got other things in the vicinity for instance, cordless telephones, then they can interfere with wireless signals to reduce the, reduce the speed, or you know, obstruct the signal in some way.

Okay.

I hope you enjoyed that lesson.

I'd love to see what kind of work you've done.

And if you'd like to share it, please ask your parent or carer to share your work an Instagram, Facebook or Twitter tagging at national hashtag learn with Oak.

I'll see you next time.