Subtitles of the Movie

Now let's go the next step. Let's talk about some subnetting Basics. Let's go back to our original 5 computer network. Now in the previous examples in the TCP IP Basics video we had these connected by a hub or a switch and now we're going to use a router because let's think about something, when we start connecting all these machines together then some interesting things start to happen. A lot of times these computers just need to talk to each other. Maybe you'll need to broadcast something to these computers, these need to work together and then sometimes talk to these people and so forth, but as your network gets a lot larger and a lot more complex this really starts to become a problem; that is, how do we control traffic flow to all these people, OK? And the answer is we can use routers and we can subnet the network and this is a very simplistic but hang in there with me. Notice that on the left side of the router here the IP address for this top machine on the left is 192.168.2.1, the bottom one is 192.168.2.2, but notice what happens on the right side: 192.168.3.1, 3.2 and 3.3. Now what's going on here? You remember that I'd said before that well that the IP address can be seen as a street and a house address and if you think about the address that if I were to send you mail, if you have a house and you're on a street then you've got a street address and a house address - 1504 Main Street - well Main Street, there are a lot of people on your street that that's part of their address. That tells us the general area. The 1504 tells us which particular house on Main Street. And , so what? we're looking at here is we could be talking about network IDs and notice 192.168.2 is the same on both of these, that is the street address and the 1 and 2 is the house address, OK? But what this really lets us do is we take a network that used to be this large and all the communication happened in this size environment and we now have divided it up really into two smaller networks. We have a 192.168.2 subnet and then we have a 192.168.3 subnet. OK? Now, this is one of the cool things that's happening all over the place with TCP IP because this lets me set up my networks however I would like to, set up as many separate neighborhoods as I want to and now I can control traffic across these two. And the router can take care of issues about moving them back and forth between the two networks. So if I do a broadcast from this computer the only people who are going to see it are the ones that are on my same subnet and all that traffic won't cross the router and come over into here; same thing for here. So when you think about subnetting I just want you to think that, okay, all I'm doing is taking my network, I'm breaking it up into smaller networks, if you will, or smaller neighborhoods on the network that can automatically communicate with each other but then they'll have to really have some help from the router to go to the other networks. OK, now this is the basis for the Internet, this is the basis for everything in TCP IP and in the next video we'll jump back into binary and take a look at how these subnets look kind of under the hood and that is where they will tend to test you, so if you're OK to this point let's go to the next video and let's talk about Determining Subnets.