I’ve Always Wanted To Know:
How does the internet work?
We take it for granted that the internet just works when we go to a website or when chatting with someone but how does it work? How does typing a letter to your friend in an e-mail program get from your computer to their computer hundreds (or even thousands) or miles away?
It’s simple and complex at the same time. Here is a flow chart describing how the information gets from your webcam to their webcam.
Your PC transfers the information the chat program sends into TCP/IP and transmits that information through a network card to your modem or router. TCP/IP is the internet standard for encoding information to signify what computer and port the information should be transmitted to. All computers currently connected to the public internet must have an IP address which is unique. Because of the limited number of public addresses some routers can use NAT (network address translation) to funnel all information through one public address but there is always a unique public address involved. This is the key piece of information which let’s the internet work because without a unique address it would be impossible for a router to determine where the information should be sent to.
The modem/router then forwards that information to your internet providers local router. That local router then forwards the information to a regional router where the internet company has connections to the “public” internet or to private peering sites. The term “public internet” doesn’t mean it’s owned by the government or free but is an exchange operated by very large communication companies to facilitate exchanging data from one companies routers to another.
The information then exists the public internet and goes to the regional router of your friends internet provider and then to the local isp router. From there the information is forwarded to the local users modem and then on to your friends PC.
The path that it takes is established by routing information contained in the router and can take different paths depending on what connection is down or overloaded. There can be multiple copies of local and regional routers depending on the setup of the internet providers network and what connection the information must travel on to get to the right destination.
You can actually see the path information takes by typing into a command prompt in windows: tracert www.google.com. You will see each “hop” or line of the trace is a different step starting with your local PC as #1 and ending with the destination’s computer.