Internet and Web

Chapter 5: Internet and Web

5.1 Introduction to Computer Networks

The digital age we live in today is characterized by significant interconnectivity. Computer Networks are defined as a group of computers and devices interconnected for data sharing. These networks allow for the distribution and exchange of vast amounts of information globally and in real-time. They come in various forms, including:

• Social networks (e.g., Facebook, Twitter)
• Mobile networks (e.g., cellular networks)
• Local networks (e.g., networks within organizations like banks, hospitals, etc.)

Network Devices

Networking devices play a crucial role in connecting computers. Standard devices include:

• Switch: Connects devices within a network and forwards data.
• Router: Connects multiple networks and directs data packets.
• Modem: Modulates and demodulates signals for internet connectivity.

Networking Topologies

These refer to how devices are arranged on a network. Different topologies include:

• Star topology: Devices connect to a central hub or switch.
• Bus topology: All devices share a single communication line.
• Ring topology: Each device connects to two others, forming a ring.
• Mesh topology: Each device connects to every other device, ensuring redundancy and reliability.
• Tree topology: Hierarchical structure combining different topologies.

5.2 Types of Networks

Networks can be classified based on their scale and reach:

• LAN (Local Area Network): Covers a small geographical area like an office or building. High-speed and secure.
• MAN (Metropolitan Area Network): Covers larger areas such as a city, connecting multiple LANs.
• WAN (Wide Area Network): Spans across cities, countries, or continents. The Internet is the largest example of a WAN.

5.3 Network Devices Details

1. Modem: Converts between digital and analog signals for data transmission over various media.
2. Ethernet Card: Connects a computer to a wired network, facilitating data transfer.
3. Repeater: Regenerates weakened signals to maintain transmission integrity over longer distances.
4. Hub: Basic device to connect multiple computers in a network, sending data to all connected devices.
5. Switch: More intelligent than a hub, sending data only to the intended recipient and forwarding multiple packets simultaneously.
6. Router: Connects different networks together, analyzing incoming data and directing it appropriately.
7. Gateway: Serves as an entry point to a network, often combining the functions of a router and firewall.

5.4 Networking Topologies

Understanding the structure of a network is crucial:

• Mesh Topology: Provides high reliability as each device connects with every other device.
• Bus Topology: Cost-effective due to fewer cables, but slower and less reliable.
• Star Topology: Reliable, as each device connects directly to a central device; however, if the center fails, the entire network goes down.
• Tree Topology: Combines characteristics of bus and star topologies in a hierarchical manner.

5.5 The Internet

The Internet connects millions of devices globally, including computers, smartphones, and IoT devices. It is pivotal for information sharing, communication, online education, and e-commerce.

5.6 Applications of the Internet

Applications include:

• The World Wide Web (WWW): A system of interlinked hypertext documents accessed via the Internet.
• Email: Allows message communications and file sharing between users.
• Chat: Real-time text communication, often through applications.
• VoIP: Enables voice calls over the Internet.

5.7 Website and Web Page

• Website: A collection of web pages typically related by a common theme accessed via a domain name.
• Web Page: A single document on the web, which can be static (unchanging) or dynamic (content changes based on user interaction).

5.8 Hosting of a Website

Web hosting involves storing website files on a server to make them accessible via the Internet. Key steps include selecting a host, choosing a domain name, and uploading web files.

5.9 Web Server

A web server delivers website contents to users upon request. It works by interpreting HTTP requests sent from clients (browsers).

5.10 Browser

A browser is a software application enabling users to access and interact with web content. Browsers support various formats and enhance user experience through settings and extensions.

5.11 Cookies

Cookies store user preferences and session information, enhancing the browsing experience but raising privacy concerns. They help in customization of web content.

Summary of Key Points:

• Network: An interconnection of computers or devices for sharing resources and information.
• LAN, MAN, WAN: Types of networks based on geographical coverage.
• Devices: Modem, switch, router, and hub facilitate network connections.
• Topologies: Arrangement of networks affects performance and reliability.
• Internet: A vast network connecting computers worldwide for communication and information sharing.
• Websites: Comprise multiple web pages with a common purpose.
• Web Hosting: Process of making a website accessible online.
• Browser: Interface for accessing the Internet.
• Cookies: Store user data for a personalized web experience.

1. Networks connect computers for sharing resources and information.
2. There are three types of networks: LAN (Local Area Network), MAN (Metropolitan Area Network), WAN (Wide Area Network).
3. Devices: Includes modems, routers, switches, and hubs.
4. Topologies: Common types include bus, ring, star, mesh, and tree.
5. The Internet is a global system connecting millions of devices.
6. Applications of internet include WWW, Email, Chat, and VoIP.
7. A Website is a collection of interlinked web pages, and a Web Page is a single document on the internet.
8. Hosting is necessary for making websites accessible online.
9. Browsers display web pages and manage internet surfing.
10. Cookies store user preferences for enhanced experience.