Answer: Domain Name, IP Address, and the World Wide Web (WWW)

1. Introduction

The internet relies on standardized addressing systems and information retrieval architectures to enable global communication between millions of interconnected computers. IP Addresses, Domain Names, and the World Wide Web (WWW) form the core foundation of this ecosystem.

+-------------------+      DNS Resolution       +-------------------+
|    Domain Name    | ------------------------> |    IP Address     |
| (www.example.com) | <------------------------ |  (93.184.216.34)  |
+-------------------+                           +---------+---------+
          |                                               |
          |       HTTP/HTTPS Request                      | Connects over
          +-----------------------------------------------> TCP/IP Network
                                                          |
                                                +---------v---------+
                                                |    WWW Resource   |
                                                | (Web Page / HTML) |
                                                +-------------------+

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2. IP Address (Internet Protocol Address)

An IP address is a unique numerical identifier assigned to every device connected to a computer network that uses the Internet Protocol for communication.

Key Characteristics:

1. Addressing & Routing: Acts as a network identifier and location address to deliver packets to their destination.
2. Versions of IP:
   • IPv4 (32-bit): Formatted as 4 octets separated by dots (e.g., 192.168.1.1). Provides $\approx 4.3 \times 10^9$ addresses.
   • IPv6 (128-bit): Formatted as 8 groups of hexadecimal digits separated by colons (e.g., 2001:0db8:85a3::8a2e:0370:7334) to overcome IPv4 exhaustion.
3. Static vs. Dynamic IP:
   • Static IP: Permanent address configured for servers.
   • Dynamic IP: Temporarily leased address assigned by DHCP.

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3. Domain Name

A Domain Name is a human-readable alias used to access websites without needing to remember numeric IP addresses (e.g., google.com instead of 142.250.190.46).

Structure of a Domain Name:

https://  subdomain .  second-level-domain .  top-level-domain (TLD)
          (  www    .       example        .         com        )

• Top-Level Domain (TLD): Generic (.com, .org, .edu) or country-code (.in, .uk, .us).
• Second-Level Domain (SLD): The organization or brand name (google, wikipedia).
• Subdomain: Specific section or server (mail.google.com, api.example.com).

DNS (Domain Name System):

The global hierarchical database that translates human-friendly domain names into machine-routable IP addresses.

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4. WWW (World Wide Web)

Invented in 1989 by Tim Berners-Lee at CERN, the World Wide Web (WWW) is an interconnected system of public hypertext documents and multimedia resources accessible over the Internet via the HTTP/HTTPS protocol.

Core Architectural Pillars of the WWW:

1. URI/URL (Uniform Resource Locator): Standardized global address to locate any document (e.g., https://www.example.com/index.html).
2. HTTP/HTTPS: The application-layer communication protocol for exchanging web documents.
3. HTML (HyperText Markup Language): The standard formatting language used to structure web content and hyperlinks.
4. Web Browsers & Web Servers: The client software that renders pages and the server software that delivers them.

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5. Summary Comparison

Concept	Nature	Function	Example
IP Address	Numerical identifier	Identifies physical machine on network	142.250.190.46
Domain Name	Human-friendly text name	Mapped to IP for user convenience	www.google.com
WWW	Global information system	Application running on the Internet	Web pages, hypermedia, web apps