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TCP/IP Protocol Suite Explained

Cyber Security Mastery: From Zero to Hero

TCP/IP: The Internet Protocol Suite

While the OSI model is theoretical, the TCP/IP model is the operational standard used for the internet. It simplifies the OSI model into four layers.

TCP/IP Layers

  1. Application Layer: (OSI Layers 5-7) Protocols like HTTP, DNS, SMTP.
  2. Transport Layer: (OSI Layer 4) TCP and UDP.
  3. Internet Layer: (OSI Layer 3) IP (Internet Protocol).
  4. Network Access Layer: (OSI Layers 1-2) Handles physical communication.

Key Transport Protocols

1. TCP (Transmission Control Protocol)

  • Connection-Oriented: Requires a three-way handshake (SYN, SYN-ACK, ACK) to establish a connection.
  • Reliable: Guarantees delivery and ensures packets arrive in order.
  • Used for: HTTP, FTP, SSH, Email.

2. UDP (User Datagram Protocol)

  • Connectionless: Sends data without prior connection setup.
  • Unreliable: No guarantee of delivery or order.
  • Used for: DNS, VoIP, Video Streaming (where speed is critical).