The internet and the world wide web
The internet is the global infrastructure. It is a vast network of interconnected computer networks that use standard communication protocols (like TCP/IP) to link devices worldwide. Think of it as the physical roads and cables.
The World Wide Web is a service that runs on the internet. It is a collection of interlinked hypertext documents (web pages) accessed via the internet. Think of it as the shops and buildings you visit using those roads.
| Feature | Internet |
|---|---|
| Definition | The global system of interconnected computer networks (infrastructure). |
| Feature | World Wide Web |
|---|---|
| Definition | A system of interlinked hypertext documents accessed via the internet (service). |
Correct Understanding: The internet is the infrastructure (the network). The World Wide Web is the information/service accessed through that network. Do not use terms like 'unreadable' to describe meaningless data; use 'meaningless'.
A Uniform Resource Locator (URL) is the unique address used to locate a specific resource (such as a web page or file) on the internet.
A URL typically consists of three main parts:
- Protocol: The method used to transfer data (e.g.,
http://orhttps://). - Domain Name: The name of the server hosting the resource (e.g.,
www.example.com). - File Name/Path: The specific location of the file on that server (e.g.,
/index.html).
Why examiners accept this: Examiners look for specific technical terms. Simply saying 'the address' is insufficient. You must identify the protocol, domain name, and file name (or path).
Example: For https://www.cambridge.org/international, the protocol is https, the domain name is www.cambridge.org, and the file path is /international.
Hypertext Transfer Protocol Secure (HTTPS) is the secure version of HTTP. It encrypts the data transferred between the browser and the server using SSL/TLS encryption. This ensures that sensitive information (like passwords or credit card details) cannot be intercepted by third parties.
Purpose: The primary purpose of a web browser is to retrieve, present, and traverse information resources on the World Wide Web. It does this by interpreting code (HTML, CSS, JavaScript) sent from a web server and rendering it into a visual format for the user.
Correct Understanding: The purpose is to display web pages by rendering HTML. Features like bookmarks, history, and tabs are functions that support this purpose. Do not state that the browser sends certificates to the server; the server sends the certificate to the browser.
Why examiners accept this: The markscheme specifically looks for the action of displaying or rendering web pages. Mentioning 'accessing websites' is often considered too vague unless linked to rendering.
Example Answer: 'The purpose of a web browser is to display web pages by rendering HTML code received from a web server.'
When a user enters a URL, the following process occurs to locate and retrieve the web page:
- DNS Lookup: The web browser sends the domain name from the URL to a Domain Name Server (DNS). The DNS translates the human-readable domain name into an IP address.
- IP Resolution: If the local DNS does not have the IP address, it queries higher-level DNS servers until the correct IP address is found.
- Request: The web browser sends a request to the web server at that IP address using HTTP/HTTPS.
- Response: The web server retrieves the requested file (e.g., HTML) and sends it back to the browser.
- Display: The browser receives the data, parses the HTML/CSS, and renders the page.
| Step | Component Involved | Action/Result |
|---|---|---|
| DNS Server | Translates domain name to IP address. |
| Web Browser | Sends request to the IP address of the web server. |
| Web Server | Sends the requested web page data back to the browser. |
Why examiners accept this: You must explicitly mention the DNS translating the URL/domain name to an IP address. Simply saying 'the computer finds the server' is insufficient. Also, specify that the browser sends a request to the IP address.
Example Answer: 'The web browser sends the domain name from the URL to the DNS server. The DNS server finds the matching IP address and returns it to the browser. The browser then sends a request to the web server at that IP address.'
Cookies are small text files created by a web server and stored by the web browser on the user's device. They are used to store information about the user or their session.
There are two main types:
- Session Cookies: Temporary files stored in the computer's memory (RAM). They are deleted automatically when the web browser is closed.
- Persistent Cookies: Files stored on the hard drive (secondary storage). They remain on the device until they expire or are manually deleted by the user.
Correct Understanding: Cookies are text files. Session cookies are in RAM/memory and are lost on close. Persistent cookies are on the hard drive/secondary storage and persist after closing.
Why examiners accept this: Examiners look for the distinction in storage location (RAM vs. Hard Drive) and lifespan (deleted on close vs. persists until deleted/expired).
Example Answer: 'Session cookies are stored in RAM and are deleted when the browser is closed. Persistent cookies are stored on the hard drive and remain until they expire or are deleted by the user.'
- The internet is the global network infrastructure, whereas the World Wide Web is a service accessed via the internet. 2. The internet connects computers, whereas the WWW consists of interlinked hypertext documents.
- Protocol (https) 2. Domain Name (www.example.com) or File Name (page.html).
- The browser sends the domain name to the DNS server. 2. The DNS server translates the domain name to an IP address. 3. The browser sends a request to the web server at that IP address. 4. The web server sends the web page data back to the browser.