Server Client

The internet is a network — an interconnected system of nodes that communicate with each other according to pre-defined protocols.

A protocol is simply a set of rules that parties agree to follow in communication, so that they can understand each other. When you order a coffee at a cafe, you follow a protocol that’s something like this:

<GREETING>
CUSTOMER: Hello.
BARISTA: Hello, what can I get for you?
</GREETING>

<ORDER>
CUSTOMER: I'd like a latte please.
BARISTA: Sure, that's $4.50.
</ORDER>

<PAYMENT>
CUSTOMER: Here you go.
BARISTA: Thank you for your business! Have a nice day!
</PAYMENT>

There are lots of different protocols, but the most common ones are HTTP and TCP/IP.