Let's assume that we have a Raspberry Pi as our client and https://www.facebook.com as our server. When our client requests a web page from the server there must be some protocols, some rules that this request will be handled. With other words, there must be a specific way of transmitting and receiving data from each other. Internet Protocols (IP) are exactly the rules according to which a client and a server talk.
There are some basic IP with which the current browsers communicate with servers and get data. However, when we talk about IoT and low power hardware, we cannot keep these protocols and use them. As a result, it is important to go through some basic stuff and know the idea behind all the communications out there.