The Basics of Internet and World Wide Web
The Internet is a massive global network of interconnected computer networks that communicate using standardized protocols. It forms the physical and logical infrastructure enabling data exchange worldwide.
The World Wide Web (WWW), or simply the Web, is a collection of publicly accessible web pages and other resources linked together via hyperlinks and URLs. It runs on top of the Internet.
Definition: The World Wide Web is an information space where documents and other web resources are identified by Uniform Resource Locators and accessible via the Internet.
IP Address
An IP Address (Internet Protocol Address) is a unique numerical label assigned to every device connected to a computer network that uses the Internet Protocol for communication.
- IPv4: Uses a 32-bit address scheme, typically represented in dotted-decimal notation (e.g., 192.168.1.1).
- IPv6: Uses a 128-bit address scheme designed to overcome IPv4 address exhaustion, represented in hexadecimal notation separated by colons (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334).
Web Page, Home Page, and Web Site
Understanding the fundamental structural units of the World Wide Web is essential for web development and internet navigation.
- Web Page: A single document containing formatted text, images, and links, viewable in a web browser.
- Home Page: The main introductory or landing web page of a website that typically serves as a starting point for navigation.
- Web Site: A collection of related web pages, images, videos, and other digital assets hosted on a web server under a specific domain name.
Types of Web Pages
Web pages are generally categorized based on how content is delivered and rendered to the user.
| Type | Description | Characteristics |
|---|---|---|
| Static Web Page | Content remains the same for every user viewing it. | Built using HTML and CSS; content does not change unless manually updated by the developer. |
| Dynamic Web Page | Content changes dynamically based on user interaction, time, or database queries. | Generated on the fly using server-side languages (like PHP, Python, Node.js) and databases. |
| Active Web Page | Contains components that execute scripts within the user's browser or on the server to alter behavior and interactivity. | Uses client-side scripting (like JavaScript) to update content in real-time without reloading the page. |
Web Server and Web Browser
Web communication relies heavily on the client-server architecture.
- Web Server: A computer system or software package that stores web site content (HTML documents, images, stylesheets, scripts) and delivers them to users over the Internet upon request.
- Web Browser: A software application installed on a client device used to access, retrieve, and view web pages on the World Wide Web (e.g., Chrome, Firefox, Safari).
Web Hosting and Domain Registration
To make a website accessible on the Internet, two primary components are required:
- Web Hosting: The service of providing storage space and computing resources on a web server for a website so that it can be viewed on the Internet.
- Domain Registration: The process of acquiring a unique web address (domain name) through a domain registrar, giving the owner exclusive rights to use that name (e.g., example.com).
DNS (Domain Name System)
Computers communicate using numeric IP addresses, but humans prefer easy-to-remember domain names. The DNS (Domain Name System) acts as the phonebook of the Internet, translating human-friendly domain names into machine-readable IP addresses.
Exam Note: DNS resolves names like www.example.com to IP addresses like 192.0.2.1 using distributed hierarchical name servers.
URL (Uniform Resource Locator)
A URL is the address of a specific resource on the Internet. It specifies the location of the resource and the mechanism used to retrieve it.
Formula / Structure: protocol://hostname:port/path?query#fragment
Example: https://www.example.com:443/products/item?id=123#reviews
- Protocol: e.g., https
- Hostname/Domain: e.g., www.example.com
- Port: e.g., 443
- Path: e.g., /products/item
- Query: e.g., ?id=123
- Fragment: e.g., #reviews
Overview of Protocols
Protocols are sets of rules governing how data is transmitted across networks.
- SMTP (Simple Mail Transfer Protocol): Used for sending and transmitting email messages between mail servers.
- FTP (File Transfer Protocol): Used for transferring computer files between a client and a server over a computer network.
- HTTP (Hypertext Transfer Protocol): The underlying protocol used by the World Wide Web for transmitting hypermedia documents, such as HTML.
HTTP Request and Response
The communication between a web browser (client) and a web server takes place via HTTP request-response cycles.
- HTTP Request: Sent by the client to the server. Contains a Request Line (method like GET or POST, URI, HTTP version), headers, and an optional body.
- HTTP Response: Sent by the server back to the client. Contains a Status Line (HTTP version, status code like 200 OK or 404 Not Found, reason phrase), headers, and the response body (such as HTML content).
| HTTP Method | Purpose |
|---|---|
| GET | Retrieves data from a server. |
| POST | Submits data to be processed to a server. |
| PUT | Updates or creates a resource on a server. |
| DELETE | Removes a resource from a server. |