AP®︎/College Computer Science Principles
The World Wide Web
When most of us talk about using the "Internet", we're typically talking about a specific part of the Internet: the World Wide Web (WWW, or simply, the Web).
The Web is a massive network of webpages, programs, and files that are accessible via URLs.
We call it a web because of its vast interconnectedness. Starting from one URL, such as http://wikipedia.org, we can follow links to eventually reach millions of webpages from across the globe.
Here's a tiny portion of that web from 2004:
Diagram of the web, with lines connecting websites based on their links to each other. More lines connect the more highly connected websites, like Wikipedia.
Powered by protocols
A web browser loads a webpage using various protocols:
- It uses the Domain Name System (DNS) protocol to convert a domain name into an IP address.
- It uses the HyperText Transfer Protocol (HTTP) to request the webpage contents from that IP address.
It may also use the Transport Layer Security (TLS) protocol to serve the website over a secure, encrypted connection.
The web browser uses these protocols on top of the Internet protocols, so every HTTP request also uses TCP and IP.
The Web is just one of the applications built on top of the Internet protocols, but it is by far the most popular.
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Want to join the conversation?
- What parts of the internet aren't part of the World Wide Web?(18 votes)
- Email or messaging would be one example, file sharing over the file transmission protocol would be another.
The world wide web is generally the part of the internet that you access using the HTTP (webpages).(31 votes)
- Are DNS, HTTP and TLS protocols exclusive to the World Wide Web?(7 votes)
- TLS is widely used outside of the www to secure network communication like messaging or email.
DNS isn't a protocol but rather a naming system.
I guess you could use DNS to handle a private network if it's large enough, but it's primarily used for the internet.
You could use HTTP on a private network, for instance an intranet might provide webpages for its members.(15 votes)
- How are the web, URLs and DNS related?(2 votes)
- The full answer to that question is way too long to fit in here, but here's a medium-sized version:
First of all, it's important to note that although all three systems are related, they can also each be used individually. However, when we're talking specifically about the Web, the structure looks something like this:
│ ┌————————┐ │
│ │ ┌———┐ │ │
│Web │DNS │URLs│ │ │
│ │ └———┘ │ │
│ └————————┘ │
To show how they are connected, take this example:
Part 1: URLs
URLs are strings used to locate resources within a computer network, like the Web.
In this example, you want to visit the Khan Academy "Computing" page, and you know the URL. The URL structure looks like this:
HTTP Khan Academy "computing"
Secure Site subdirectory
So now we have a string that indicates the location of a web page, but we have no idea where in the world it is located. This is where DNS comes in.
Part 2: DNS
DNS is like the phone book of the Internet; it takes in domain names (much like human names) and turns them into IP addresses (much like phone numbers).
So the domain name https://www.khanacademy.org (ignore the https://) is sent to a DNS server, which looks in its database, and finds something like this:
https://www.khanacademy.org = 126.96.36.199
It then sends the IP address 188.8.131.52 back to your computer.
Part 3: Web
Finally, your device has all the information it needs. It sends out a request to the Khan Academy server located at IP address 184.108.40.206 with the URL https://www.khanacademy.org/computing.
The server replies with the web page showing all the computing courses on Khan Academy.
I have left out a few details, so if you want to learn more of the specifics of how this all works, I suggest reading Wikipedia.(24 votes)
- So, is the world wide web on an upper layer than the internet or vice versa?(3 votes)
- The World Wide Web is a subset of the superset that is the internet.(3 votes)
- What's an Internet protocol? Is it a law governing what should and shouldn't be online?(3 votes)
- Internet Protocol or IP is a set of requirements for addressing and routing data on the internet. It allows devices to contact each other. HTTP and HTTPS are forms of IP. It could be thought of as rules, but it's more just a set of requirements. If the item does not meet the requirements it doesn't work.(2 votes)
- Which websites shouldn't we trust? How do we know if it's a false website?(3 votes)
- There are some ways.
First - try to remember websites' domain names to which you may transfer sensitive information. For example your hospital site is princeton-plainsboro.med. You want to send them your blood test results you made in other clinic. Your health information is personal and sensitive information and shouldn't be shared without your consent. So you google Princeton Plainsboro and click first link. You are directed to very much similar site with domain name princeton-plainsb0ro.med. As you can see there is a difference in domain names. So you got into fishing site. They can even have SSL certificate but even then they can steal your data.
Second - if you are planning to transfer ANY data to a site check if site is reached via HTTPS and has a valid SSL certificate. Browsers usually show a locked lock sign before a address line if there is a valid SSL certificate. That certificate is used to encrypt data you send to server and reverse.(2 votes)
- is it possible have a URL we own that is connected to the WWW and following public DNS to also be connected to a "subnet" that uses a private DNS system to then direct traffic within that website based on that private "intranet"?
more specifically, can it be done in a way that does not require a person to connect to that private dns? but rather be "served" the content like a Gateway?(3 votes)
- Why a picture from 2004?(3 votes)
- in simple word a webpage allow access to another webpage via URL right? and so on we can form a massive network of webpage(2 votes)
- How do you classify parts, if they are from the world wide web or not?(1 vote)
- Here is a video that may help to clarify the difference: https://www.bbc.co.uk/newsround/47523993(2 votes)