To understand how data travels across networks, we need to explore the TCP/IP and OSI models. These models provide frameworks for how data is transmitted over networks.

The TCP/IP model is a four-layer model used to conceptualize how data is sent and received over the internet. It includes the Application, Transport, Internet, and Network Interface layers. Each layer has specific protocols that handle different aspects of data communication.

Link Layer: Equivalent to OSI’s Physical and Data Link layers.
Internet Layer: Handles IP addressing and routing (corresponds to OSI’s Network layer).
Transport Layer: Ensures reliable communication (TCP) or faster, connectionless transfer (UDP).
Application Layer: Includes protocols like HTTP, DNS, FTP, and SSH.

The OSI model is a seven-layer model that provides a more detailed framework. It includes layers such as Physical, Data Link, Network, Transport, Session, Presentation, and Application. While not used directly in networking, it helps in understanding and troubleshooting network issues.

Physical Layer: Deals with the physical connection between devices (cables, switches, fiber optics).
Data Link Layer: Manages MAC addresses, ARP, and Ethernet communications.
Network Layer: Handles IP addressing and routing (IPv4, IPv6, routers, ICMP).
Transport Layer: Ensures end-to-end communication and data integrity (TCP vs. UDP, ports, segmentation).
Session Layer: Manages sessions and authentication between applications.
Presentation Layer: Handles data encryption, encoding, and formatting.
Application Layer: Provides end-user services such as HTTP, DNS, and FTP.

Intro to Networking Fundamentals