TCP/IP & Networking Fundamentals

Master the OSI and TCP/IP models, understand IP addressing, learn common protocols, and explore the TCP handshake for building a solid foundation in network communication and security.

OSI Model (7 Layers)

The Open Systems Interconnection (OSI) model is a conceptual framework for understanding network communication. Each layer has specific functions and communicates with layers above and below it.

7

Application Layer

User applications and services (browsers, email, FTP, DNS, HTTP, HTTPS)

Example: Gmail, Telnet, SSH, HTTP requests

6

Presentation Layer

Data formatting, encryption, compression (JPEG, MPEG, SSL/TLS)

Example: Data encryption, character encoding, compression

5

Session Layer

Manages connections and sessions (RPC, NetBIOS, Sockets)

Example: Managing login sessions, maintaining connections

4

Transport Layer

End-to-end communication and data delivery (TCP, UDP)

Example: TCP connection establishment, UDP datagram transmission

3

Network Layer

Routing and logical addressing (IP, ICMP, IPsec)

Example: Router decision making, IP addressing, ping requests

2

Data Link Layer

Physical addressing and framing (MAC, ARP, VLAN, STP)

Example: MAC address translation, frame creation

1

Physical Layer

Raw bit transmission (cables, hubs, fiber, radio waves)

Example: Ethernet cables, WiFi signals, fiber optics

OSI Model Encapsulation Diagram

OSI Model encapsulation showing data flow through layers