Terms like weigh in and land should be, in my opinion, pretty straightforward for people who are approaching the security plus exam. However, there are lots of network topology concepts that are on the test. So what I'd like to do in this episode is just take a few minutes, and I use the word review. If it's new to you, you get to learn something, but the different types of network topologies. Now, before we get started, make sure you understand that a network topology is basically the actual organization of a network in terms of how is the data moving around. And the best way to get started with this is to begin with the most basic of topologies, the local area network or a LAN, as you see in this diagram, what we have is a number of computers.
And all of these computers are connected together to one box called a switch. Now keep in mind, it doesn't have to be one switch, there could be two or three switches. And it doesn't have to be just a few computers. It could literally be Hundreds and hundreds of computers. But what's important as we look at this is that all of these computers are connected into what we call a broadcast domain. Now when I say a broadcast domain, all I'm saying is that if an individual computer sends out a broadcast, all of the other computers that hear that broadcast our members of the broadcast domain, so that is a classic local area network.
Now, what we can do here is we can extend that land. Let's say for example, we take that one land and break it up into 234, or five, six different lands. We interconnect these with one or more routers to generate what we call a wide area network or a LAN. A wide area network absolutely must have at least two local area networks and at least one router. However, we can scale this up if we want to. Now imagine all of the different wide area networks that are in The Houston Texas area.
So if we scale this up, here's Houston. Now all of a sudden, we've got all of these wide area networks that are within Houston. And even these wide area networks can connect together to create what we call a metropolitan area network. Now you got to be careful here that Metropolitan Area Network is also a wide area network, a wide area network that connects to other wide area networks is still a wide area network. What makes it a metropolitan area network is that it spans a city. Now, you could have a lot of variations to this.
You can have campus wide networks, you can have county network. So the geographical space just gives you an idea where the interconnections are taking place. In fact, let's scale this up even more. Now. I know some of you folks aren't in the US, but here's the continental United States. And let's scale up all of these wins all over the United States.
And now start to connect these guys together. What we've generated down folks is The Internet. And I guess I should extend this worldwide now. And even in outer space, the International Space Station, they have a really good internet connection as well. So what you're doing is you just keep connecting lands and connecting lands and connecting lands until you completely cover the entire world, and you get the internet. Now, there's a little more to it than that.
The other thing you got to keep in mind is that the protocol which runs the internet is TCP IP. TCP IP is free. It's extremely well known. And anybody can use TCP IP, even if you're not on the internet, as long as you're using legitimate IP addresses, like here's an ipv4 address, or how about an ipv6 address. If you're using the TCP IP stack, and you're making your own LAN or when or whatever you want, you are now creating the intra net. So an intranet is nothing more than a private network.
Which still runs on TCP IP. Now we can take this one step further. And here is my intranet. But way out somewhere I've got, in this case, some vendor who needs access to my databases or something like this. So I give that vendor a internet connection into my network so that they can do whatever they need to do. And that's a great example of an extranet.
Now, again, hopefully for most of you guys, this is very much a review episode. But do keep in mind on the security Plus, it will throw these terms out hot and fast. These are not the types of things you want to install on when you're going through some challenging security plus questions.