Networking Fundamentals – Internet, WWW, Hosts & DNS

TCP/IP Stack (4-Layer Model)

• Application Layer: Handles application-specific protocols (e.g., FTP, HTTP).

• Transport Layer: Manages data flow and error checking (e.g., TCP, UDP).

• Internet Layer: Routes data packets across networks via IP addresses.

• Network (Link) Layer: Manages physical transmission of data.

• This is the TCP/IP stack.

Internet vs World Wide Web

• Internet: A global network of interconnected computer networks.

• WWW: A system of interlinked web pages and resources accessed via the Internet.

Internet Hosts

• Devices that store and make files accessible online (e.g., web servers, file storage).

Web Servers & Web Clients

• Web server: Stores web content and responds to requests from web clients.

• Web client: (e.g., Browser) Sends requests to servers and displays web pages.

• Operates on a client–server model.

URL Structure & IP Addresses

• URL parts: Protocol, domain name, path, page name.

• Each URL links to a unique IP address (e.g., 2001:0db8:85a3:0000:0230:8a2e:0370:7334).

• Domain names are for humans; IP addresses are for machines.

Domain Name System (DNS)

• DNS: Translates domain names into IP addresses.

• Resolution: Browser asks DNS for an IP address, DNS provides it, browser then requests content from that IP.

Key Vocabulary

• Internet

• WWW

• Host

• Web Server

• Web Client

• URL

• IP Address

• DNS