You’re on vacation in Italy, sitting at a nice café (with free Wi-Fi). It’s a few days into your trip now and you’ve taken some beautiful photos that you want to share with your parents back home.
Mom and Dad aren’t too familiar with Dropbox or Google Drive, so instead, you attach the photos to an email.
Your mouse hovers over the send button and click…almost instantaneously it shows up in your Mom and Dad’s inboxes halfway across the world.
What just happened?
First, Some Network Basics
Before we even get into how the email got to your Mom, halfway across the world, we need to understand the physical components of a network.
Networks are groups of interconnected devices. Any device that is connected to a network is known as a node. Most modern networks contain the following nodes:
- Network Interface Cards / Network Adapters
- Wireless Access Point
1. Network Interface Cards
Also known as Network Adapters, Network Interface Cards are hardware that’s installed in computers, such as your laptop or PC. Though not a node themselves, they allow computers and electronic devices to join a network as a node.
Switches are central nodes that forward messages between nodes in the same network by rapidly creating and deleting connection points.You can think of them as the managers of the network, maintaining the flow of information between the devices in a network, whether wireless or wired.
A router is a device that connects two or more separate networks. Routers forward data to other routers of different networks until the data has reached its destination.
4. Wireless Access Points
WAPs allow nearby computers and nodes to interact with a network wirelessly, usually via Wi-Fi. They’re nodes that provide wireless capability to a wired network.
Multiple WAPs can be connected to extend the wireless capability range of a network, such as in a large building. However, WAPs aren’t a required component of a network, as networks can remain completely hardwired.
Quick Note: Wi-Fi Connection vs. Internet Connection
Contrary to popular belief, Wi-Fi does not have anything to do with your internet connection and the two terms should not be used interchangeably, although they often are.
Wi-Fi only applies to the strength of your connection to a Wireless Access Point Located in your Local Area Network. Internet connection measures the strength of your router’s connection to the internet. You can have a strong connection to your Wi-Fi, but no connection to the internet or vice versa.
Here’s another 8 things you didn’t know about WiFi.
The Birth of the Internet
The origin of the internet began in the late 1960’s and early 1970’s from a new network technology created by the U.S. Department of Defense. It was known as the Advanced Research Projects Agency Network (ARPANET).
Its purpose was to connect various Department of Defense scientists and researchers across the United States working on defense projects. Researchers incorporated ARPANET into the networks they were working at including universities. As more and more networks joined the system, the internet began to take shape.
So, What is the Internet?
In basic terms, the internet is a global interconnected collection of networks that communicate using internet protocols (wait, how do protocols work?). You can think of it like a network of networks where every network is a node.
However, new devices and technologies have created new ways to connect to networks through the internet. A combination of them is often used to make these connections.
1. Wired Internet
This is the most common form of connection to the internet. Hundreds of thousands of miles of wires are laid throughout the world. They range from phone lines (DSL) to fiber optic cables.
Data can travel up to 70% the speed of light through ideal wire mediums such as fiber optic cables, which allow extremely fast transfer of data.
Many of these wires are laid underground or underwater to prevent degrading. On land, along with being underground, they’re also placed with utility lines that travel along roads.
Single lines can span thousands of miles, such as the underwater transatlantic communications cables that connect various parts of the U.S and Canada to Europe. This is the ideal and fastest way to access the internet.
2. Satellite Internet
People who have satellite dishes on their roofs are connecting to the internet via satellite. This is usually required when there are no wired connections available in the local area to connect to the internet, such as third world countries and areas with low populations.
Though satellite is relatively fast, it’s still slightly slower than wired connections due to longer transmission distances (up and back down instead of across). Also, if the final address for the data isn’t within range of the satellite (like sending that email to your parents), the data needs to passed from satellite to satellite until it arrives at one that is within range.
3. Cellular Internet
A relatively recent addition, cell phones have joined the internet. Cell phones connect using cell towers, which then connect to physical wires and to the rest of the internet.
In a sense, cell towers are sort of like extremely wide Wireless Access Points, except they’re only for cell phones or data enabled devices. Cell phones may also act as wireless routers using mobile hotspots, in which a laptop or similar device could connect using Wi-Fi to access the internet.
Ok now about that email…
How Does the Internet Work?
As you close your laptop and continue your journey across Italy, your email is on a journey of its own, albeit a much faster journey.
When you clicked send, your laptop’s Network Interface Card sent the data in the email to the Wireless Access Point using Wi-Fi. The WAP then sent the data through a wire to the local router.
The local router took that data and sent it to another router, which then sent to another router, and another router, all the way through a chain of routers until the data was transferred over one of the transatlantic communication cables to the United States.
There, it ended up at a Google data center (because your parents use Gmail) and Google then sent a notification to your parent’s laptops stating that they’d received a new email.
Mom sees it first, goes to her email account, and clicks on the email. The data is transferred from the Google data center through multiple lines and reaches the router of your mom’s home, which then goes through the Ethernet cable she has connected to her computer, through her laptop’s network interface card, and is finally displayed on her screen.
All in the blink of an eye. Cool huh?