Introduction to the Internet

The Internet

• A global network connecting billions of computers and devices
• Allows people to access information and communicate worldwide
• The world's largest network, connecting hundreds of thousands of smaller networks globally
• Often called the "information highway" because it transports ideas and information through cyberspace
• Cyberspace is the digital space where data moves electronically
• No one owns it
• No formal management structure exists
• The Department of Defense originally developed it
• Its decentralized design made it more resilient to wartime or terrorist attacks
• To access requires a small registration fee and adherence to TCP/IP standards
• TCP/IP stands for Transmission Control Protocol/Internet Protocol

Uses of the Internet

• Email is one of the oldest and most widely used ways to communicate and share information, used by billions of people
• File sharing allows sending (uploading) or receiving (downloading) files between computers or devices
• Social media platforms like Facebook, Instagram, and Twitter help people connect, share content, and build online communities
• Online shopping enables buying products or services from anywhere in the world with just a few clicks
• Managing finances allows paying bills, transferring money, and managing bank accounts online
• Entertainment includes streaming movies, music, and playing games online
• Education facilities access to online courses, tutorials, and educational materials
• Work and collaboration tools like video conferencing, cloud storage, and project management platforms enable remote work and collaboration

The Web

• Also known as the World Wide Web
• It is a collection of websites accessible via the Internet
• A website consists of related text, images, and other resources
• Websites can resemble traditional media or be interactive
• The Web is made up of information organized into web pages with text and graphic images
• Web pages include hypertext links, highlighted keywords, and images that lead to related information
• A collection of linked web pages with a common theme is called a website
• The main page that all other pages on a website link back to is known as the home page

Internet Access

• Many schools and businesses connect directly to the Internet through high-speed communication lines and specialized equipment
• Students and employees connect via the organization's local area network (LAN) or personal computers
• Another way to access the Internet is through an Internet Service Provider (ISP)

Data Packets

• A small bundle of data sent over a network
• Facilitates information travel on the Internet and other networks
• Used in Internet Protocol (IP) to help computers communicate and share information

Internet Service Provider (ISP)

• A company with a permanent connection to the Internet
• The company sells temporary connections to its customers.
• Some examples are Smart Communications, Globe Telecom, DITO, Sun Cellular, Converge, and PLDT

Web Access

• Web access requires a special software called a web browser
• Web browsers allow connecting to remote computers, opening and transferring files, and displaying text and images
• Web browsers help you find and view sites or information on the Internet
• Some examples are Netscape Navigator, Internet Explorer, Microsoft Edge, Google Chrome, and Safari

Client/Server Structure

• The Web consists of files on web servers worldwide, connected through the Internet
• Computers act as web clients in a global client/server network when connecting to the Web
• Web browsers enable computers to function as web clients for accessing the Web

Hypertext Markup Language (HTML)

• The most basic building block of the Web
• HTML stands for Hypertext Markup Language
• Defines web content organization and meaning
• Files stored on web servers are usually plain text files similar to those in word-processing programs
• Hypertext refers to links connecting web pages within or across websites
• Hypertext links makes it easy to navigate
• HTML uses "markup" to annotate text, images, and other content for display in a web browser
• HTML includes special "elements" like head, title, body, header, footer, article, section, p, div, span, and img

IP Addressing

• Every computer connected to the Internet has a unique IP (Internet Protocol) address, which identifies the computer
• The most common type of IP address has four parts, such as 106.29.242.17, with each part being a number between 0 and 255 separated by periods
• IPv6 is newer and looks different, such as 2001:4860:4860::8844, and can support more devices than the older format
• An IP address is made up of four parts and allows for about 4.2 billion possible unique addresses (256 x 256 x 256 x 256)
• By 1998, it became clear we would soon run out of available addresses
• Teams of experts are working on a new addressing system to handle the growing number of devices connecting to the Internet
• Implementing these solutions will require significant changes to both the hardware and software used across the entire Internet

Domain Name Addressing

• Most web browsers use domain names instead of IP addresses to find websites and individual pages
• A domain name is a unique name that points to a specific IP address
• This connection is managed by DNS (Domain Name System) software, which runs on a server
• DNS helps translate the easy-to-remember domain names into the numerical IP addresses that computers use to communicate
• The computer that runs the DNS software is called a domain name server (DNS)
• Domain names can have multiple parts separated by periods, most commonly three or four
• They follow a hierarchical structure, and their organization is understood by reading from right to left
• No two computers on the Internet can have the same domain name

Uniform Resource Locator

• Also known as URL
• A way to identify where a file is located on the Internet
• While IP addresses and domain names point to a computer, they don’t show where a web page's HTML document is stored
• Web browsers use URLs to find this exact location
• URLs have four parts:
  • The transfer protocol used for sending the file
  • The domain name of the computer where the file is located
  • The path to the folder or directory on that computer where the file is stored
  • The name of the file itself
• HTTP is Hypertext Transfer Protocol

Transfer Protocols

• A set of rules that computers follow to move files from one computer to another on the Internet
• The most common protocol used for loading web pages is Hypertext Transfer Protocol (HTTP)
• Other protocols include File Transfer Protocol (FTP) for transferring files and Telnet Protocol for accessing remote computers

Finding information on the Web

• A number of search tools have been developed
• Available to users on certain websites that provide search services to help find information
• Examples are Yahoo, Google, Lycos and AltaVista
• Information is found online by searching by topic or by keywords
• Search by Topic: You can explore lists of topics to find information related to your interests
• Search by Keywords: You can type a specific word or phrase into a search box to look for relevant information
• Search engines like Yahoo and Google offer both methods to help you find what you're looking for.