Internet--> OSI Model--> Protocols

Created2020-12-30Updated2021-01-14

Internet: network of networks

“How internet works?” sounds like a simple question as we use internet almost anywhere now. Many people think internet is about connecting to Wi-Fi or using cellular data to browse websites or send messages to friends. I realise it is way more complex than that when I dive into this topic. For me, there are two sentences to conclude “internet”:

  • It is a network of networks.
  • It is about encrypting data and transferring data.

For example, we can form a private network to connect the devices together in our house. A school can build its own public network. The purpose of the network is to share the resources on different devices with each other. If a network is a small unit, internet connects many of the units together globally.
The OSI model is used to explain the story behind the scenes.

OSI Model: a standard for networks

When we browse a website using our computer, our device is a part of the network. Before we get the resource (web pages for instance) sending back from the other device remotely, we are actually sending our data first. But we do not realise this step as it is not showing on the screen. The data containing what we want, who we are, which browser window we are using, which device we are using, where we are living and where the data should go. The data also needed to be encrypted in terms of security purpose. When the data reaches the other side, it will be decrypted, and the device will prepare the resource we want. The similar process will happen again to send the data back to us.
The OSI Model (Open Systems Interconnection Model) describe the steps(layers) how a computer preparing data and transferring data to the right location(device).
Within the OSI mode, there are lots protocols available to make the process work and one of them is HTTP protocol.

Protocol – HTTP

Each step(layer) of preparing or transferring data has different protocols. If the data type is HTML files, the protocol can be HTTP protocol. In other words, if we design a web app, we need to use HTTP protocol to make the app understand the data coming through then sending back data that the browser can translate and displaying on the screen.

Reference:
https://www.youtube.com/watch?v=eKHCH6rw0As&list=LL&index=4
http://www.steves-internet-guide.com/tcpip-ports-sockets/
https://www.youtube.com/watch?v=x3c1ih2NJEg