How Internet Works?
Internet is more of a virtual thing to us, just like electricity. But it is not, there are lines connecting all the computers even the popular term “cloud” mislead us thinking the internet is living in the sky.
Internet is a huge web of computers, messages sending back and forth between those computers, how does these messages travels? Well, how do we travel around the world? Catching a bus, taking a taxi, heading to railway stations, airports. The digital messages travel very similarly.
IP address & DNS
As each house attached to a unique address, computers has their IP address, which is 4 piece of numbers, each number range from 0–255, like 188.8.131.52. Now very familiar? You are right, the numbers are hard to remember, so Domain Name System(DNS) comes to rescue. We type “www.google.com”, it actually goes to DNS servers first to fetch the corresponding numeric IP address which is “184.108.40.206”
ISP & Routers
The messages carried with destination IP address are sent out to travel to the destinations. It first run into Internet Service Providers(ISP) who own or rent the bandwidth for transferring those messages. But we can’t just connect every two computers directly like there is no direct bus route for every two houses, we use Routers to make the distribution. Routers are tiny computers holding the IP address tables, those addresses are the computers connecting to that router, when the router receive a message, it will exam if the destination address is recorded in the address book, if yes, directing the message, if no, send upward to larger hubs, until it finds the destination. Type “traceroute www.google.com” in the terminal, you can see how the system route all the way to Google.
But you might wonder, the messages we send out are text messages, how do they travel on the telephone lines? Well, that’s why we set up protocols to transform alphabetical text to electrical waves. The message will be divided into several chunks, adding ‘port’ number of the destination application(each application on computer is listening to a port), then add IP address before getting to hardware layer where those messages are transformed to signals to transfer.
For different data format we usually have different protocol, for example, HTTP, FTP etc. When you type in the browser search bar, the address is actually “Protocol:IP address/Port number/Filename”, like “https://medium.com/a3b16cdffxxxx”
This is a very high level of how internet works, but I think it is sufficient for a beginner front end develop. Next, we need to learn what is HTTP and how browsers work in depth.