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Lesson 01 - Introduction to Networking

Summary

In this lesson you'll learn what a network is and be able to explain how different people look at a network. You'll also learn a little bit about a WAN, an Enterprise network and the Internet.

Elements of Communication

When communicating there are five things required in order to have successful communication.
  • Sender
  • Receiver
  • Message
  • Medium
  • Common Language
All five are needed to have communication take place, if any element  is missing then communication fails.  

There are two elements worth mentioning that aren't needed to have successful communication, but they might exist so it's worth mentioning. 
  • Security
  • Error control
 
Identify each in the following types of communication. Also identify security and error control if applicable.
  • Teacher in front of the class
  • Telephone conversation
  • TV transmission
  • Texting
  • Concert

What is a Network

A network can be defined as a combination of hardware, software and cabling, which together allow multiple computing devices to communicate with each other. Below we see an example of a network. In the diagram we see computers, a server, a printer, and a cloud. The cloud contains some stuff that isn't important to us at this point. The server is there to provide services to the users. This is an example of a small network.

As you can see from the image above there is a lot that is unknown about this network.  Throughout the course we will be revealing more and more detail about the network, both physically and logically.

Using a network

There are times when you use the network and you know you're using a network.  When you browse the Internet you know the pages you're viewing exists outside your device.  You know in order to view websites your device has to request them from somewhere else and they're sent to you.  They don't exist on your device.

There are other times when you know you're using the network.  When you post a message on Facebook you know people will see that message from their own devices.  They won't have to use your device to see the message.  The message travelled over a network to Facebook's server.

You know when you are downloading or uploading files you are using the network to transfer the data.  Downloading is getting a file from a network source.  Uploading is putting a file onto a network destination.

There are other times when you may use a network and not even realize it.  If you walk into a computer lab and sit down at a computer next to a printer.  When you print you may not know if that print job went over the network, or a USB cable.  You probably don't care either way, you just grab your print job and go.

Another time you may use the network and not know it is when you save a document.  If you save it to your Documents folder you may think you're saving it to the local disk, but in reality you're saving it to the server.  All you know is your data is there when you want it, so you don't care where it is.  

These are examples of using the network either on purpose, or by accident.  Sometimes you know you're using the network, sometimes you don't.

Different Types of Networks

Networks come in many different shapes and sizes, we will look at a couple of other example before we go any farther.

LAN - Local Area Network
The small network that we have been looking at is a Local Area Network, or a LAN. The LAN has a few characteristics such as:
  • Limited geographical area - Usually limited to one site.
  • High speeds - 10Mbps or higher, today speeds usually start at 100Mbps.
  • Locally owned media - The cable that runs through the walls and ceilings is owned by the company.
  • Transparent Use - User of network resources should be transparent to the user.
WAN - Wide Area Network
When you have a need to span your network over a larger area you create a Wide Area Network, or a WAN. A WAN is a way to connect LAN's that are far apart. A WAN has the following characteristics:
  • Wide geographical area, such as a state, country or world.
  • Lower speeds - Usually 1.5Mbps or slower, although WAN speeds have been increasing over the years.
  • Media is not locally owned, you usually lease it from a company for example, the telephone company
The Internet
The Internet is another network that we all use. This is a global network that people all over the world connect to and use to share information. Users connect to the Internet by using an Internet Service Provider (ISP) that connects you to the Internet.

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