TCP IP Model Overview - buaamer81/IT130-Networking-Wiki GitHub Wiki

TCP/IP Model Overview

📘 Overview

The TCP/IP Model (also known as the Internet Protocol Suite) is a 4-layer framework used to describe how data moves across networks, especially the internet.

It is the practical model used in real-world networking — while the OSI Model is more theoretical.

Think of it as:
“The working model of the Internet.”

🧱 The 4 Layers of TCP/IP Model (Top to Bottom)

TCP/IP Layer	Corresponding OSI Layers	Function
Application Layer (TCP/IP)	OSI Layers 5, 6, 7	Provides services & applications
Transport Layer (TCP/IP)	OSI Layer 4	Reliable or unreliable data delivery
Internet Layer (TCP/IP)	OSI Layer 3	Logical addressing and routing
Network Interface Layer (TCP/IP)	OSI Layers 1 & 2	Physical transmission of data

🆚 Key Differences: TCP/IP vs OSI

TCP/IP Model	OSI Model
4 Layers	7 Layers
Practical, used in real networking	Conceptual, used for learning
Developed by DARPA	Developed by ISO
Internet-based	Vendor-neutral

📦 Data Units at Each TCP/IP Layer

TCP/IP Layer	Data Unit
Application	Data
Transport	Segments / Datagrams
Internet	Packets
Network Interface	Frames / Bits

🔄 Protocol Examples per Layer

Layer	Protocol Examples
Application	HTTP, HTTPS, FTP, DNS, SMTP
Transport	TCP, UDP
Internet	IP, ICMP, ARP
Network Interface	Ethernet, Wi-Fi, MAC Addressing

🧠 Real-Life Scenario

You browse Google:

HTTP operates at Application Layer
TCP ensures reliable delivery at Transport Layer
IP provides addressing at Internet Layer
Ethernet or Wi-Fi at Network Interface Layer moves the bits physically

📊 Visual Aids

🧪 Labs and Practice

Lab 3: Tracing TCP/IP Packet Flow using Wireshark

🔁 Related Pages

Return to: Chapter 2