(3) TCP/IP and OSI Model Introduction

TCP/IP and OSI Model Introduction

• The TCP/IP and OSI models are crucial for understanding network communication
• The OSI model, developed by the International Organization for Standardization (ISO), is a conceptual framework for standardizing network functionalities
• The OSI model consists of seven layers: Application, Presentation, Session, Transport, Network, Data Link, and Physical
• The Application layer handles user applications
• The Presentation layer translates and encrypts data for the application layer
• The Session layer manages sessions and dialogues between applications
• The Transport layer ensures reliable data transfer
• The Network layer routes data, handles addressing, and forwards packets
• The Data Link layer manages node-to-node data transfer and error detection
• The Physical layer handles the physical connection and raw data transmission
• The OSI model serves as a universal guideline for network interoperability
• The TCP/IP model, developed by the U.S. Department of Defense (DoD), has four layers: Application, Transport, Internet, and Network Interface
• The Application layer in TCP/IP focuses on user interfaces and higher-level protocols
• The Transport layer manages end-to-end communication and data transfer
• The Internet layer handles routing and addressing of data packets
• The Network Interface layer focuses on network interfaces for data exchange

TCP Connection Observation using Wireshark

• A TCP (Transmission Control Protocol) connection, at the transport layer, follows steps:
• A three-way handshake (SYN-SYN-ACK-ACK) establishes the connection
• Data transmission occurs in segments, acknowledged by the receiving device
• Wireshark is a network protocol analyzer, used to capture, inspect, and analyze network traffic in real-time.