Understanding Local Area Networks. Part 1

A free video tutorial from Melbourne Gregory
M.S., M.B.A
Rating: 4.4 out of 5Instructor rating
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Understanding Local Area Networks. Part 1

Lecture description

In this module, student will learn about Local Area Networks (LANs), Network Devices, and Data Transfer.

Learn more from the full course

Computer Network: IT Networking Fundamentals 2016

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02:14:15 of on-demand video • Updated March 2016

This courses address Local Area Networks (LANs), network definition using the OSI model, wired and wireless networks, Internet Protocol (IP), TCP/IP in the command line, networking services, wide area networks (WANs), and much more
Understanding Local Area Networks: Learn about local area networks (LANs) including network devices, data transfer, and types of LANs. Explore network topologies and access methods. Compare peer-to-peer and client/server network models.
Defining Networks with the OSI Model. ​Get to know the OSI model, and explore switches. Review the layers in the OSI and TCP/IP models, plus review different types of switches.
Understanding Wired and Wireless Networks including an overview of twisted-pair and fiber optic cables, and an overview of wireless devices and wireless networking standards.
Understanding Internet Protocol: Review IPv4 and IPv6. Review IPv4 address categories, default gateways, DNS servers, and subnetting.
Implementing TCP/IP in the Command Line: Basic and advanced TCP/IP commands.
Networking Services: Look at topics related to understanding common networking services and different name resolution techniques.
Understanding Wide Area Networks. Explore routers and WANs. See how routers function, including how data can be routed statically or dynamically, and learn how WANs are connected.
Learn about concepts of the Internet.
English [Auto]
I everyone I'm instr. Gregory and welcome to network and fundamentals. This is module one. The very beginning and we're going to focus on understanding in the where that works. Thanks for joining me. I'm really excited to teach you about that because let's get started. All right so let's do a quick overview of our agenda. First we're going to discuss a local network and then talk about the data transfer on a Local Area Network also known as a man. And then we're going to feature different types of local area networks that you may run across. All right so what is a network. A network is just two devices that are connected to each other with the physical medium like oh why your cable or radio signal and that connection allow the two devices to exchange data back and forth. Networks have a lot of different purposes. They're used for communication and collaboration inside of a business or an organization. They allow us to share information like in resources like your tweets and your texts and they make it possible for us to organize data but they also allow us to save a lot of cost because we can share resources like printers and other services that are available through networks. All right. So our network is organized right. We have all the devices around the world but how are they organized well one another. They're organized based on their geographic locations. Remember that networks are organized based on their geographic location right where they are in the world or in a building or a city and a local area network specifically is simply a group of computers or devices that are featured in the same small geographic location. All right so let's repeat that networks will organize based on what their geographic location and local network are. It is a group of computers that are featured in the same small geographic location. So think of like a school or a small office thats a local area network. Now the the computers and the devices on a local network share a common communication media. So we have cables like we talked about earlier or a wireless connection. Right. And these computers and devices are also connected to something called a central connected device. We'll talk about those in a little bit. Right. But those are like your hubs and your switches and your routers. Right. And these devices are very important for you to learn about. All right. So what devices may come in a local area network. We have a host like your phones laptops desktop PCs servers and tablets right. And we also have central connected devices which are your hubs your switches and your routers. Now we typically interact as users with host machines and those host machines that connect to central connected devices which are responsible for relaying our data to other host machines. A host is defined as any device that has something called an IP address and IP address is used to send or receive information. It is very similar to the mailing address at your house. It helps to identify not only the device but also the network in which they are located. And if you go back to that home address analogy a network could be something like your city or maybe even your street block central connected devices or for a connected host and also transmit data. Now different central connected devices perform these functions in different ways. All right so I'm going to show you a model. OK first we can start talking about hubs. Host send data to a hub and then broadcast that data to other devices that are connected to it. Now this is sort of an antiquated technology it's very old. It's becoming more and more obsolete. So take a look at this model on the right I have here. Now if the computer at the top census data every device connected to a hub is going to receive that data. Now the potential problem here is that this computer may only want to send the data to the laptop down at the bottom of the screen and not to the server that's located at the top. Right. We were able to correct this problem with the help of devices costs which is unlike hobs switches send and receive data to their intended destination. All right so take a look at the example here on the right. You got data being sent simultaneously. And they also go specifically to their intended target. So a good way for you to Rupes summarize it is that switches are simply monitored and Harp's. Let's talk about routers routers are at the edge of the loquitur network and they are responsible for connecting us to the Internet or they act as a gateway to other networks. So routers allow communication between hosts on other Nogueira networks all these devices connect to each other by way of network adapters and network adapters also known as a network interface cards. Now these pieces of equipment make it possible for our computers and even our cell phones to communicate with each other now and network interface card communicate by way of wire and wireless signals. If you look at the example on the right. Why don't adapters features an RJ 45 ports and wireless adapters feature an antenna and connect to networks use in a wireless access point. Ethernet cables are made up of copper wires and they transmit data in the form of electrical pulses. Now wireless communication and contrasts rely on an entirely different technology. Radio signals right now as I said copper cables transmit data in the form of electrical pulses. So if there's a pulse then that might represent a state call on and no pulse then represent a state call off and we normally say that a pulse will be represented by a 1 and then no pulse will be represented by a 0. Right. And this is called binary. You'll learn more about this as you learn more about network so here we talk about wireless access points. They provide a central point of access for your laptops and your cell phones and even your PCs and we can wirelessly transmit data on these wireless access points which are actually connected to switches and routers. So even though we access the network wirelessly that data is still transmitted across the wired network. All right so let's switch mode and talk about data transfer on a gray area network. All right so data is transferred in a serial format. Right. So what does that mean. Instructor GREGORY That means one bit of data at a time is. And you know that it can travel in any single bitstream in both directions. And to and from and how does that depend on the type of connection. All right. Even a couple of different connections so if you look at the the the model we have here on the right arm first we have something called the simplex right which means it's like a one way street. Right. And data can only transfer from one device to another whereas you have something called Duplaix which is like a two way street. And this means as you can guess that it can be sent and received at the same time simultaneously. And there's also something called a half duplex. Now this is kind of unique because this is like you have a two way street but only one of them is in use at any given point in time so that it can be sent and data can be received but not at the same time. The speed that data travels is measured by bits per second and that's called the data transfer rate. And we signify that data transfer rate as you can see in my illustration here at the bottom right. Right. So we have the number 10 here right. And then we have the M which in this case stands from megger and then we have the lowercase b in this lowercase b is a little bit different from the type of data that we store and represent bits. Right. Not to be confused with a capital B which represents bytes. Right now this whole construct you see I have here it's called the bitrate. And we use that to measure how fast data transfer over a network before data is transferred it actually goes to a really interesting process. We break down large chunks of data into things called segments right and then address information is wrapped around that segment and we call it a packet. Right so take a look at the illustration I have here right now from there we are a little bit more information in order to make it something called a frame. Right. And then each frame is broken into bits that we can see on your screen right now. This visual that I have here may be a little bit confusing but I just want you to know one thing. Data is ultimately going to be represented in bits before it's transmitted across a network. Right. So this whole thing end up taking this form right here that you see right and then is transmitted over a physical media in binary. All right. Of course when data is received by a device like your cell phone or your computer it goes through the reverse process. So what happens is that the receiving computer is going to take all those bits and it's going to read the frame reassemble the Ethan and frame and it's going to strip the physical information and then it's going to strip the logical address and information known as your IP address right. And so it's no longer a packet anymore. Right. It's going to come back into its segment form and then it's going to be reassembled into the fire that you and I click on in like your Windows Explorer or your in your Google Chrome whatever browser you use. Right. Which I think is a really cool process and actually really simplifies the way data transfer occurs. All right so how does data know where to go. Well we mentioned IP addresses right. And those are your logical addresses that uniquely identified the device and its network. So an example here would be 192 and that 168 that won that one. Right. And every IP address is broken down into two different parts by something called the Southern mask. And we'll detail that here in a little bit. And so we have a network I.D. portion which is your 192 168 or one. And then we have your host ID which is one. Now this network ID it's like a city right in the state. And I guess maybe your street name. And then we also have your host ID which would be like your house number. All right. Another thing that's really worth mentioning is that the IP address is right the way they appear know that these little dots right between your 192 they have yet dot the 160 dot. You know that split up the different numbers those separate artists. Right. And our kids are actually just 8 bits right and they are 4 octets and an IP address which means an IP address is 32 bits. So 32 zeros and ones it like I just said we're going to touch on subnet mask now and detail that and a little bit of a subnet mask is just the group of four numbers that define a computer network. Right. So look here and the model that I have at the bottom right the 2:55 represent the network portion of an address. Right. So 192 that 168 that one just like the example we saw earlier. OK. And the zero represents the host portion. All right so that's like your street address. In contrast all of the here EPROMs everything is represented by 2:55 is going to be a network portion. Right now this is really important for us to keep in mind as we learn this right and we're going to revisit this throughout the course. All right. So finally our last objective types of local area networks. Right. We have wired local networks that comes in different forms and these wired low loquitur networks. Each PC is connected to a central connected device. Does that sound familiar. We talked about it earlier right. And whether it's a router or a switch and that happens by way of an ethernet cable or a copper base twisted pair cable we also have wireless local area networks where each of our devices is going to connect to a network way of a wife signal and then transmit data ultimately onto a wide network. All right. And the host on this network will connect through a wireless access point. Right. So this is a great alternative to your wired network. It definitely provides a level of convenience and flexibility that the wired network just doesn't. And finally we have a very special type of local area network called the Virtual loquitur network or a VPN. Right. And in a villa and devices are based or grouped based on their functions. So keep that in mind physical location of these devices does not matter at all. You can have two devices sitting right next to each other but they're treated as if they're on completely different local area network. Right. So it's a really cool technology and it's something that make it definitely a lot easier for you to manage your network and keep some devices more secure. All right. And you know it provides a different sense of right to different devices based on their organization. All right. Thank you so much for joining me here. Let's do a quick recap of our agenda again. OK. So we covered local area networks and we talk about what local networks are right. And we discussed data transfer in general on a local area network. How did it get from one place to another. And also we talked about the different types of local area networks. All right I'm really excited to continue our journey through network and fundamentals again so I'll see you again in modules.