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What is a network?

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This is talk the type of tick tock.

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Do you like tick tock?

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What is your favorite tick tock videos?

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Cats you like cats on tick tock.

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You learning about Kenay and then you also going to learn about hacking.

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Is hacking your favorite if you want to be a hacker poodle.

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Well done, poodle.

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You've got a lot of learning to do.

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So today we're going to learn about what is a network.

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Now, if we're going to talk about networking, we should really define what a network is.

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So what is a network now?

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I'm not talking about a social media network.

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I'm not talking about your contacts, let's say, on Facebook or LinkedIn or Twitter or tick tock or

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whatever.

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Your social media platform of choices we're not talking about is social media network.

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In this case, we're talking about a computer network.

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So what is a computer network?

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And she has a challenge.

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I'm going to ask the robots what a computer network is.

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See how much you understand by this definition.

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Alexa, what is a computer network?

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A computer network is a digital telecommunications network for sharing resources between nodes, which

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are computing devices that use a common telecommunications technology, data transmission between those

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who supported over data links consisting of physical cable media such as twisted pair of fiber optic

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cables, or by wireless methods such as Wi-Fi, microwave transmission or freespace optical communication.

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OK, so there's the course we finish now.

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We all understand what computer networking is.

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Yeah, if only now, if you're a robot, you may be able to understand everything about computer networking

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just by listening to those two paragraphs.

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But I think for us, we need to spend quite a bit more time to really understand what a computer network

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is and understand how computer networks work.

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Let's start firstly with the why.

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Why do we have computer networks?

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What's the whole point of the Internet?

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What's the whole point of all this infrastructure that's been built around the world?

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And the big reason to have a network as per this definition is to share resources.

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We want to share information or share some kind of resource with someone else.

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Now, what is a resource?

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In the old days, a common example of a resource would be a printer.

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If you had an office with 100 people in the office, you could buy a printer for every workstation or

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for every PC.

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And that's what they had to do before the days of networking.

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They either had to have a printer for every computer or have no printers, or what they had to do is

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do something like this where they copy a file onto a floppy disk and then go over to the printing station

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and then print it manually.

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It's not cost effective to buy a printer for every workstation or for every person.

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It makes much more sense to have a centralized resource, in this case a printing resource, and share

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that resource amongst the people in the office.

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So rather than having, let's say, 100 printers for 100 people only, let's say have 10 printers.

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So you've reduced the cost by creating a shared resource, a resource that can be shared by what are

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called clients.

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So we have client devices or PCs in this example that are sharing a resource, in this case a printer.

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Another example is file sharing.

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This is very common.

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I want to share a file with you.

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So how do I do that now?

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In the old days, the way to do that was to get a floppy disk like this.

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The problem with these floppy disks is in the old days, they're only supported one point for four megabytes.

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It's not a very big drive, but there you go.

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Really old example.

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So they'd have to if they wanted to share a photograph or a file with someone else that have to copy

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it to this floppy disk, then walk using what we would call sneaker net.

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So they'd firstly have to copy the photo or the file onto this disk, then walk using sneaker net across

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the office, put it into the other computer and then access the file.

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So that's how they would share a resource in this case, a file or a photograph.

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Now, today, we still use this kind of technology by using USB thumb drives.

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So if I wanted to share a resource with you, like a photograph or a file, I could copy it onto this

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USB drive and then give it to you and then you'd copy it to your computer.

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So sneaker net, the original type of networking, if you like, is where a human being would take a

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resource.

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I'd copy a file or a photograph onto this USB drive.

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I'd walk to your computer and then give it to you and share the resource with you.

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But that's not very effective.

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It's not scalable, doesn't work that well.

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You let's be honest, most humans would be too lazy to have to walk around the office to share files.

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It's much easier just to share files using a digital transmission mechanism or medium, and they're

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different types of digital transmission mechanisms.

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Why are we doing this?

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We are trying to share a resource between what in this definition is called a node, and they define

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that as a computing device.

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So a node is a computing device and there are many types of computing devices.

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We could have windows, laptops, we could have Mac books, we could have phones, we could have servers.

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Those are often the devices that most consumers will think about.

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And I've mentioned printers already has another one.

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But in networking we have specialized devices such as hubs, switches, routers and firewalls to name

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a few.

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So stepping back a second, why do we have a computer network we want to share resources, which could

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be a printer, could be a file, could be a video.

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So four videos are very popular these days.

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You watching this video through a computer network?

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I'm sharing this information with you using a data link in the Wikipedia definition.

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They talk about a data link being a physical cable such as trusted pay fiber optic cables, Wi-Fi or

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some type of data link where I'm sharing information with you.

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So the big idea here is I'm sharing a resource with you and I need a way.

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To get that to you, you need a device that could receive the resource, we need some kind of transmission

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media, which could be physical cables or it could be wireless.

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So the idea is, rather than having to physically transport a file on a USB drive or in the very, very

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old days using a floppy disk, we use a cable or some kind of mechanism to transmit data from one device

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to another or from one device to many devices.