02 - Networks and The Internet | 01. Overview Of The Internet

Question 1

When did the internet start?

Answer 1

1969

Question 2

Who created the precursor to the internet?

Answer 2

United States Department of Defense funded the creation of ARPANET, a precursor network to the internet

Question 3

What does ARPANET stand for?

Answer 3

ARPANET stands for Advanced Research Projects Agency Network

Question 4

What did ARPANET do?

Answer 4

ARPANET connected supercomputing centers run by government agencies and universities.

Question 5

What was created to standardize the transfer of data between all of these early networks to communicate with one another?

Answer 5

In the 1970s, the transmission control protocol and internet protocol, otherwise known as TCP/IP, were created to provide standards around the transfer of data that would allow these early networks to communicate with each other.

Question 6

When was TCIP/UP researched and implemented?

Answer 6

TCP/IP was researched and specified throughout the 1970s and adopted in the early 1980s. As different networks adopted TCP/IP, the interconnected global network of networks that is today known as the internet was formed.

Question 7

Which places/universities were early ARPANET institutions?

Answer 7

Westcoast: SRI, UCSB, UCLA, SDC, RAND, UTAH
Eastcoast: MIT, BBM, HARVARD

Question 8

T/F | The “internet” and the “world wide web” are the same thing?

Answer 8

FALSE. While people today often use the terms internet and world wide web interchangeably, they actually refer to quite different things.

Question 9

What is the “internet”?

Answer 9

The internet refers to the actual network of connected computing devices. Although the internet was around in the 1980s, there was not an intuitive way for most people to browse the internet. The internet just sent messages produced by one computer and presented them to another computer.

Question 10

When did the world wide web happen and who brought it about?

Answer 10

1989 when Tim Berners-Lee invented the world wide web.

Question 11

What is the “world wide web”?

Answer 11

The world wide web is a collection of interlinked websites and other web resources. The world wide web, in combination with the rise of web browsers in the 1990s, introduced a user-friendly interface that enabled users to browse multimedia content and interact with other users.

The invention of the world wide web led to the use of the internet in wider society through the 1990s and the creation of a variety of websites that are still in use today.

Question 12

The internet is a network that links computer devices worldwide, enabling people to share information with one another despite vast distances. But how is information sent from one device to another?

Answer 12

Servers

Question 13

What is a server?

Answer 13

A server is a specialized computer connected to a network which provides, or “serves up”, resources or services. The role of this computer is to listen to requests from network devices and send back data.

Servers are not like computers we know. They don’t have monitors and keyboards since they are focused on storage.

Question 14

What happens when you request a website in your browser?

Answer 14

When you type a web address and press enter a series of things occur:

1. The request is sent from your device to a server across the internet as a “client request” for the files that make up the website.
   Browser -> Client Request -> Web Server
2. The contacted server is dedicated to holding the websites files
3. Once the server receives the request it contains logic for processing the request and identifying the files the client has requested.
4. The web server responds to the browser request with the necessary files.
   This is what allows the browser to show the website files to you.
   Web Server -> Server Response -> Browser

Question 15

What are some popular web browsers?

Answer 15

Safari, Mozilla, Chrome, Explorer, Opera

Question 16

What is the purpose of a browser?

Answer 16

To display websites for you to read and interact with.

Question 17

How do browsers and servers communicate?

Answer 17

The browser and server communicate with one another using the internet protocol known as HTTP, or Hypertext Transfer Protocol, which allows for data transfer.

Question 18

What does HTTP stand for?

Answer 18

Hypertext Transfer Protocol.

Question 19

What is happening when you see an S at the end of HTTP what is happening?

Answer 19

An S at the end means the data is being transferred securely

https://

Question 20

What are the common HTTP method requests?

Answer 20

GET, POST, PUT, DELETE

Question 21

What does the HTTP Request method GET do?

Answer 21

GET is used to retrieve information from the given server.

Also can be when a user wants to “fetch” data

Question 22

What does the HTTP Request method POST do?

Answer 22

POST is used to send data to the server (like customer information or a file upload)

This could also be when a form is being submitted

Question 23

What does the HTTP Request method PUT do?

Answer 23

PUT is used to replace current data with uploaded content

Question 24

What does the HTTP Request method DELETE do?

Answer 24

DELETE removes current data

Question 25

What is a browsers key function?

Answer 25

The browser initiates a requests to the server and renders website files.

Question 26

What is the key function of HTTP?

Answer 26

A standardized protocol for how browsers and servers connect and speak to one another.

Question 27

What is a servers key function?

Answer 27

The server stores website files and sends them to the web browser upon request.

Question 28

What are HTTP status codes in the client-server model?

Answer 28

When a server responds to a client, the server specifies a status code as a part of the response. Status codes indicate whether or not the HTTP request was successfully completed and if there was an error, they contain some information about the type of error that happened. The status code helps the browser know how to handle the data that was sent back with the response.

Question 29

What are some common status code numbers?

Answer 29

200, 301, 404, 500

Question 30

What does the HTTP status code 200 mean?

Answer 30

200, OK. The request has succeeded

Question 31

What does the HTTP status code 301 mean?

Answer 31

301, Moved Permanently. The resource has been moved and the client is being redirected.

Question 32

What does the HTTP status code 404 mean?

Answer 32

404, Not Found. The requested resource was not found.

Question 33

What does the HTTP status code 500 mean?

Answer 33

500, Internal Server Error. The server encountered an unexpected error.

Question 34

T/F | Most of the time, our devices aren’t making a single request between a client and a server.

Answer 34

TRUE
But most of the time, our devices aren’t making a single request. Every time we load a webpage, our device sends a request for each file that makes up that page. So even when we’re just loading one webpage, that page can make multiple requests in order to retrieve different pieces of content, like images.

Question 35

What are the steps when we’re making multiple requests simultaneously between the browser and the client?

Answer 35

All of the following steps happen in a split second:

1. When a user types in a URL and presses enter, the server processes the request and sends the HTML file back to the client. HTML files hold the content of a website and they also contain links for any additional assets or code that are needed to display the site properly.
2. The browser will begin to search for elements in the HTML file and it will start to make additional HTTP requests for any other external resources used by the HTML file. This often includes:
3. One or more CSS stylesheets. CSS stands for cascading style sheets; CSS creates the style and layout of a web page. The browser will request the CSS stylesheet, and when the server sends it back, the browser analyzes the CSS and starts applying the visual styles to the content of the site.
4. The request-response cycle also sends website assets, like images and videos, from the server to the browser. If these files are large, there might even be a noticeable delay before they are rendered by the browser.
5. One or more JavaScript files. JavaScript makes the webpage interactive. This programming language functions as the “behavior” of the web page. A webpage that does not use JavaScript is known as a static webpage.

Question 36

T/F | In most modern browsers, these additional requests are made in parallel. This means that these requests are initiated at the same time, and the browser does not wait to receive one resource before requesting the next resource.

Answer 36

TRUE

Question 37

T/F | All of the resources are typically displayed as soon as possible. The HTML will not be displayed even if some of the other assets have not been received by the browser.

Answer 37

FALSE

All of the resources are typically displayed as soon as possible. The HTML WILL BE displayed even if some of the other assets have not been received by the browser.