INT - Internet (Lesson)

The Internet

What is the Internet?

Let's begin by watching this video from code.org answering the question "What is the Internet?"

IP (Internet Protocol)

IP stands for Internet Protocol. Watch the video below to find how the request from your computer gets to where it needs to go and returns information back to you.   Note that this is done in small pieces called packets. Packets allow information to travel in smaller pieces across the internet allowing faster travel of all information. The information must then be reassembled when received. One way to think of the IP packets is like a letter you receive in the mail.  Each letter has a return address (the IP address of where the packet is coming from), a destination address (the IP address of where the packet is going), and the data which is the content.  The internet protocol routes the packets on the internet from one destination to another.

Routers connect to the network.  You probably have one in your home that connects to your Internet Service Provider (ISP) which in return connects to the Internet.  One of the functions of the router is to forward the data packets between networks.  When a packet hits the router, the router reads the IP address and continues forwarding.  There are multiple paths the router could send the packet but typically, the router looks for the shortest point.  The router knows this because it has a forwarding table.  This forwarding table helps pick the path for the destination IP address.

How the Internet Connects

View this video on how the Internet connects.

Transmission Control Protocol (TCP)

Now what happens if a router is down?  Is that packet lost?  The answer is no.  Remember the router looks for the fastest route but that is not the only route.  Because there are many paths, this increases the network redundancy. Network redundancy ensures network availability in case of device or path failure.  This redundancy also creates a fault-tolerance system.  A fault-tolerance system is one that can experience failure(s) in some of the components but continues to operate by following different routes. Another way to state this is there is no single point of failure.

Packets can be destroyed or lost.  That is where the Transmission Control Protocol (TCP) comes in.  TCP is used with IP to ensure the reliability of the packet being received.  Because of this, you will see the protocol combined which is TCP/IP (Transmission Control Protocol / Internet Protocol).

Now watch the more detailed information on packet switching. Information that you request or send over the internet is broken into packets, not necessarily traveling the same method to the destination computer and then reassembled to be handled by the receiving computer.  In the below learning activity, you will examine how a data file is broken into packets and transmitted over the Internet.

Packet Switching

For years, the only internet addresses were IPv4 but we have outgrown this limited number of unique addresses.  Why?  Think about all the Internet of Things (IoT).  Smart watches connect to the internet, wildlife cameras, cars, smart refrigerators, NEST controlled temperatures, etc.  Because we are running out of IPv4 addresses, IPv6 is now the new standard.

Earlier we mentioned all the possible items in a household that may connect to the internet and how the internet has grown.  The protocols which power the internet and the Web were designed to grow.  That means the systems are scalable.  What is scalability important? One big benefit is if a device uses the proper protocols, the device can be connected to the internet regardless of the location.  The IPv4 addresses had limitations but now with the IPv6, the IP address connections are limitless thus enabling the scalability, the addition or subtraction of devices on the internet.  The internet is accepting of as many devices as we want to connect.

But, we are limited by bandwidth.  Bandwidth is the maximum amount of data that can be sent in a specific time period; the maximum capacity of an internet connection. Because time is a factor, bandwidth is calculated in megabits per second (Mbps).  Think of it as the size of the pipe carrying the bandwidth.  The bigger the pipe, the more bandwidth.  Have you ever noticed how slow the internet gets when a bunch of people in your area start downloading or streaming movies?  Or when 3 people connected to one router play an online game?  The more being downloaded, the slower the download becomes. 

Now here is where some confusion comes in.  Internet speed is not download speed.  Internet speed is the transfer rate from a source system to the destination system in megabits per second.

Another term you may hear is latency.  Latency is the delay or the time it takes for a signal to reach its destination and back.  The lower the latency, the better.   For example:  you click on an address to get a webpage.  Latency is the time it takes the browser to get and show the webpage to you.

The last term for us to talk about is throughput measured in bits per second or data packets in a time slot. Throughout tells you how fast data is actually transferred on a network. 

Let's look at the video on IP and DNS.

Internet tools are applications (apps) and software that help us, the end user, be more productive, have fun while learning, or even provide music you like to hear. Here we will look at a couple of internet options and continue looking at different ideas throughout the course. Let's start with some of the tools that are social, that bring the world together as a community. These tools let you talk and discuss all over the world and have had significant impact on the world around us.

VIDEO SOURCING FROM CODE.ORG & KHAN ACADEMY Links to an external site..  USED ACCORDING TO TERMS OF USE.