Wednesday, September 16, 2009

How Does The Internet Work?

Our Internet is slow right now. I was asked by one of our student journalists to explain how the Internet works and why is it suddenly slower this year.

Mark Ordonez and I put this response together. How do you think we did? What could I add or change?

1. How does the internet actually work?

The Internet itself is a series of lines that are connected by pieces of equipment that send information to and from computers located all around the world. The lines can be electrically based (phone lines, T1, T3, etc) or can be light based (fiber optics). When a connection is made to a location it connects to pieces of hardware called routers and switches. These pieces of equipment determine where to request information from or where to send it. Each router, server, and computer has an address, called an IP address, that allows other computers to find it.

To give a concrete example:

If you are in the library at Maine South and you go to Google for a search. You first enter in a URL (universal resource locator) into your browser. The browser first breaks the URL http://www.google.com into two parts. The first part tells how to find Google and the second part tells the browser what to find. The first step is to find the address for Google and the browser asks a directory for the IP address of Google. The response comes back to your computer with a numerical address (the IP address) for Google instead of the words you typed into the browser. Then your request for the web page found at http://google.com heads out to the Internet. The request leaves your computer, travels through a series of wires, switches, and routers at Maine South, it then travels through fiber to Maine East, goes through a filter to make sure that your request is appropriate, and goes to a location in downtown Chicago and in connected to the Internet though our service provider. The request to see the web page at Google is forwarded to Google's server which then listens for what type of information you are looking for. In this case, it knows you want their front page of google.com, finds that page on its network, and sends it back your computer. Google knows where to send the page to because your request comes with a return address (your computer's IP address). Your browser then displays the information it receives from Google. It has to repeat these steps for each item on the page, such as the Google logo.

2. What makes one Internet's speed slow versus another one that is fast?

The speed of your Internet is determined by the speed of the network that is carrying your requests and the power your computer has to interpret those requests. Your computer receives back information from the Internet that comes in series of ones and zeros called bits. Your computer can only listen to and translate the bits into what is displayed on your screen at certain rate based on the power of your computer. At Maine South there are a variety of computers that have differing processing power based on the hardware inside of them. A more powerful computer will process the bits and display them to you faster than a less powerful machine. The second limiting factor is the speed that the network can send and receive bits which is limited by the smallest pipe that information is flowing through. The size of the pipe is measured by the amount of bits it can carry per second. At Maine South the information travels in a pipeline that can carry 100 million bits per second (100Mbps). Once it leaves Maine East and goes out to the Internet it has to flow through a pipe that can only carry 21Mbps. This where some of the slowdown can occur. Your request to the Internet is being pushed through that pipe along with requests from everyone else. If more than 21 million bits arrive at that point at any single time a back up occurs as bits wait to go out or come back in. This traffic jam is what slows down the Internet.

There are 2 ways to increase the speed of the Internet experience. The first is to have a more powerful computer, but it is not the most efficient way to speed up how you interact with the Internet. The best way to speed up your Internet experience is to increase the size of the smallest pipe that leads to the Internet so that less traffic jams occur. It would be like saying you don't need a faster car to get downtown you just need a wider highway to reduce congestion.

The size of Maine South's pipeline is currently limited based on a calculation determined by the government organization that provides Internet to most schools, libraries, and hospitals in Illinois. Those calculations allow us to have a pipe that is 21Mbps, but through a special program we were allowed a pathway of 47Mbps for the last few years. Recently budgetary limitations placed on our government sponsored Internet provider caused them to remove the special program Maine 207 was participating in causing our bandwidth being reduced to 21Mbps. This is why the Internet has been slower this year in comparison to last year. The District is currently working to fix this problem by acquiring a larger pipe out to the Internet so there is less of a chance for slower traffic. We expect this to be completed in the next few months.

For a quick video explanation of the Internet take a look at this video

0 comments: