Network & Internet basics.
Tags: student
Published: 2020-11-16 10:38:05

Network & Internet Basics

The Internet is a large network of computers that communicate all together, when two computers connect together they connect with either an ethernet cable or a wireless wifi signal that connects them. 

It's like a road that connects you from your house to a shop, servers are highly functional computers that are connected to the internet. Servers store webpages, apps, files and etc in their SSD harddrive. 
Servers are like the shop you want to buy something from, 

Data centers are big buildings with many servers or highly functional computers, that store the data in the servers. We have a few here in Iceland and it seems like it's a growing business here since we have a lot of space and a cold climate, which helps with keeping the centers cool, so they don't need to use a lot of energy to cool it down.

Everything connected to the internet directly or indirectly has an Ip address, so servers, clients, routers, cell phones, and so on.
Like Google server has a special protocol address, or IP address it has 72.14.205.100 and your personal computer has one as well. That's why DNS was invented or Domain Name Server, it's like a huge phonebook that connects all the names to the IP addresses, so every time you hit Google.com you are directed to the 72.14.205.100  IP address.

Our personal computers are not servers, they are clients that are connected to an internet service provider like Vodafone or Síminn and they connect us to the internet.

When information or data is sent through the internet the information is usually broken down into smaller pieces or packets as they call it.

Anywhere the internet intersects there is a Router, Routers direct your packets where to go. Every time you visit a webpage there may have been 10-15 routers direct you on the way.


•Your internet connection:
 Allows you to send and receive data on the web. It's basically like the street between your house and the shop.

•TCP/IP: 
Transmission Control Protocol and Internet Protocol are communication protocols that define how data should travel across the internet. This is like the transport mechanisms that let you place an order, go to the shop, and buy your goods. In our example, this is like a car or a bike (or however else you might get around).


•DNS: 
Domain Name Servers are like an address book for websites. When you type a web address in your browser, the browser looks at the DNS to find the website's real address before it can retrieve the website. The browser needs to find out which server the website lives on, so it can send HTTP messages to the right place (see below). This is like looking up the address of the shop so you can access it.

•HTTP: 
Hypertext Transfer Protocol is an application protocol that defines a language for clients and servers to speak to each other. This is like the language you use to order your goods.


•Component files:
 A website is made up of many different files, which are like the different parts of the goods you buy from the shop. These files come in two main types:
o	Code files: Websites are built primarily from HTML, CSS, and JavaScript, though you'll meet other technologies a bit later.
o	Assets: This is a collective name for all the other stuff that makes up a website, such as images, music, video, Word documents, and PDFs.

(This information was taken from „www.developer.mozilla.org“)




When you type in a webpage, your browser goes to the DNS server(„phonebook“) which looks up and finds the Ip address of the server that is hosting that website you want to look at.

There are two types of hosting, traditional hosting that's in servers, inside data centers and the other one is in the cloud or called cloud hosting, like in Github. Cloud hosting has been getting a very good reputation for its versatile scaling options, data security, mobility control, efficiency and cost reduction, disaster recovery. Many web owners are moving their webpages from traditional hosting to cloud-based hosting these days.

After the browser has found the IP address it sends an „HTTP“  message request to the server for a copy of that webpage to the client. This message and all the data is sent between clients and servers on the internet using the TCP/IP. After the servers accept requests it sends all the files in packets back to the client. 
Which then we can finally look up, the webpage he or we typed in.