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Hello, my name is Mrs. Holborow, and welcome to Computing.
I'm so pleased you decided to join me for the lesson today.
We are going to describe the roles of protocols in communication, and why IP addresses are used in networks.
Welcome to today's lesson from the unit, Computer Networks and Data Transmission.
This lesson is called Protocols and IP addresses, and by the end of today's lesson, you'll be able to explain how devices on a computer network use protocols to communicate.
It would be useful if you have your worksheet ready.
Should we make a start? We will be using these keywords during today's lesson.
Protocol.
Protocol, a set of rules used to allow devices to communicate with each other.
Network.
Network, a group of devices connected together wirelessly or using cables, to enable communication.
IP address.
IP address, a unique identifier such as 192.
168.
4.
8 that is assigned to a network device.
There are two main parts to today's lesson.
We'll start by describing the role of protocols in communication, and then we'll move on to explain why IP addresses are used on networks.
The first part of the lesson is describe the role of protocols in communication.
All methods of communication need rules in order to pass on a message successfully.
These sets of rules are called protocols.
For example, in the UK, there is a protocol for people to shake hands when they're meeting in a formal situation.
Computers use protocols to allow devices to communicate with each other.
Protocols are the rules computers use to transmit data across networks.
This ensures that data is transmitted reliably and efficiently.
For example, your device may be made by one manufacturer, and the person you are communicating with might have a device made by another manufacturer.
Need to make sure that they have the protocols, or agreed rules, so that those devices can communicate with each other.
Okay, time to check your understanding.
Why do computers need protocols when communicating over a network? Is it A: With no protocols computers may send data to every device on the network.
B, to ensure that data is sent to the correct device in the correct format.
Or C, using protocols helps data travel faster.
Pause the video whilst you have a think That's right, well done, B is the correct answer.
Computers need protocols when communicating over a network to ensure that data is sent to the correct device in the correct format.
Here are some examples of protocols.
Let's start by looking at email addressing protocols.
We have to use the @ symbol, and the email address must be unique.
For example, andeep.
singh@example.
com.
Website addressing protocols.
All website addresses start with either http:// or https://.
All website addresses are unique.
And dots are used to separate each part of the address.
Here's the example.
https://www.
example.
com.
Jacob here has got a really good question.
"What would happen if one of these protocols is not followed?" What do you think might happen? Oh, Sofia says: "It's important that the protocols are followed in computer networks to prevent errors." These kind of errors may be things like emails may not be delivered, emails might be delivered to the wrong person.
A webpage may not be found, or the wrong webpage may be opened.
Time for a check.
What is missing from this email address to make it work correctly? Sofia oaknationalacademy.
org.
Is it A, an @ symbol? Is it B, it needs to start with either http:// or https://.
Or, C, it needs to end with.
com.
Pause your video here, whilst you have a think.
Did you remember those email protocols? All email addresses must have an @ symbol, so that's what's missing from this email address.
Well done.
It's now time to move on to our first task for today's lesson.
You're doing a great job so far, so well done.
Here, I have six envelopes with six addresses.
Which of these do you think will reach the person at their destination? Pause the video here, whilst you complete the activity.
That's right, only the middle one at the bottom would reach their destination.
And that's because it's the only letter with the combination of all of the bits of information.
So we have the person's name, we have the number that they live at, and the street.
We have the town, and we have the postcode.
None of the others have all of the pieces of information.
I'd now like you to imagine you are writing a letter to your favourite author.
What rules do you need to follow to make sure that the postal service sends the letter to the right person? And then list the rules that you need to include in the letter.
So for example, what does a standard letter look like? Pause your video here, whilst you complete the activity.
You were asked to imagine you were writing a letter to your favourite author.
You were first asked what rules you'd need to follow to make sure that the postal service sends it to the right person.
You would need to make sure you have the correct address, the correct name, that the envelope was sealed, and that it had a valid stamp that would cover the postage.
You were then asked to list the rules for what you needed to include in the letter.
You could have had things like, "Dear Laura", at the top, or "Dear Author".
You needed to have the address at the top and the date at the top.
And then, maybe your signature or name at the end.
How do these answers compare to what you had? If you need to make any more notes, you can always pause the video here.
Okay, for the final part of Task A, I'd like you to answer this question.
Why do computers need protocols to communicate on a network? And what do these protocols do? Pause the video here, whilst you complete the activity.
How did you get on? Great work so far, well done.
Here's a sample answer.
Protocols are like the instructions or rules for how computers send data to each other on a network.
They make sure the messages are sent in the right way, arrive at the right place, and are understood correctly.
We are now gonna move on to the second part of today's lesson explaining why IP addresses are used on networks.
Jacob's got a really good question again.
"Why does the postal service need an address and postcode on a letter?" Can you think why this might be the case? Ah, good response, Sofia.
"So they know exactly where to deliver the letter to." On a computer network, the router needs to know which device to send the information to.
So each device on a network needs to have a unique IP address.
This is the same as our addresses in the postal system.
Everybody's address is unique, because we have different house or flat numbers, and we have different postcodes for different areas.
An example IP address could be 192.
168.
5.
43.
IP stands for Internet Protocol, and we've seen the term protocol is used for agreed methods of communication.
In this type of address, the correct format is four numbers separated by a dot.
So we can see here we've got 192.
168.
5.
43, all separated by a dot.
And only numbers between zero and 255 inclusive are used.
So you can see in my four numbers, there are no numbers that are less than zero or more than 255.
Local networks are networks that connect devices together in one location such as a school.
IP addresses are used to identify devices connected to local networks, even if they're not connected to the internet.
Time to check your understanding.
Which of the following IP addresses has the correct format? Is it A, 192.
168.
256.
1.
B, 192.
16.
8.
12.
1.
C, 192.
168.
12.
1.
Or, D, 192.
1.
68.
12.
1.
Pause your video here, whilst you have a think.
Did you select C? Well done, 192.
168.
12.
1 is the only IP address here with the correct format.
That's because it has four numbers separated by a dot, and the numbers range from zero to 255 inclusive.
Here we have a diagram of a network.
The IP address is unique for each device on the network.
Notice, how all the network devices in the diagram have different IP addresses.
And this isn't just the computers or laptops, it's also the servers and router.
Jacob's got another great question.
"Why is it important that each device has a different IP address?" Maybe pause the video here and think about that question yourself.
Ah, Sofia is saying: "Because the network must be able to identify each device uniquely and accurately to deliver the correct information to the right device." Think about if you were on the school network and you'd requested a particular website, but that website got returned to somebody else who was on the school network at the same time.
Time for a check.
Each device on a network has a unique IP address.
Is this true or false? Pause your video, whilst you have a think.
That's right, it's true, But why is it true? It's true because the network must know which device is which to accurately deliver information to it.
When data is sent over a network, the router will add the IP address of the receiving device.
This makes sure that the data is sent to the right device.
The router also adds the IP address of the sending device.
So here are some examples.
We've got the To and the From, and you can see we've got the IP addresses in the format that we've just discussed.
Jacob's got a question.
"Why does the network need both the sender and receiver's IP address on the data?" Pause your video, whilst you have a think.
Oh, Sofia's got a brilliant response.
"So that if there's a problem delivering data, the sending device can be informed." This may mean that the sending device could resend the information if there was a problem.
Okay, you're doing a great job so far, so well done.
We are now moving on to the final set of tasks for today's lesson.
So for Task B, part one, I would like you to draw arrows from the sending device to the receiving device for each message on the left.
Pause the video here, whilst you complete the activity.
How did you get on? Great work.
You were actually playing the role of a router there.
You can see I've drawn on the arrows for all of the messages, but let's just take one of the examples.
We've got a laptop here with the IP address, 192.
168.
5.
1.
And that laptop actually sent two messages.
So I've got two arrows coming out from that device.
One of those messages went to another laptop with the IP address.
192.
168.
5.
5.
And the other message went to another laptop with the IP address 192.
168.
5.
6.
Did you put all the arrows on correctly? Don't worry if you didn't.
You can always pause the video here, and correct your response.
Now for parts 2 and 3.
For part 2, explain what happens if a device on this network gets disconnected.
And for part 3, explain why it is important to have the sender's IP address on network messages.
Pause the video, whilst you complete the questions.
Let's have a look at some sample answers.
So you were asked, What happens if a device on the network gets disconnected? A disconnected device will not be able to send data to other devices on the network.
It won't be able to send emails, share files, or participate in online games with other connected devices.
You are then asked to explain why it's important to have the sender's IP address on network messages.
It is important to have the sender's IP address on network messages, so that if there's a problem delivering the data, the sending device can be informed, and in some cases, may be asked to resend the message.
You have done a great job today, so well done.
Let's summarise what we have learned in this lesson.
Protocols are rules that ensure data is transmitted reliably and efficiently across networks.
Each device on a network needs a unique IP address, like a home address for your computer.
Messages on a network include both sender and receiver IP addresses to allow for returns if needed.
I hope you join me again soon.
Bye.
