Claviro

Networks Foundation

OSI and TCP/IP Introduction

OSI and TCP/IP Introduction

Build a first mental model of communication layers and packet encapsulation.

Beginner Level

Create the foundational layer model used in all deeper networking and security analysis.

Click the numbered markers on each diagram to explore the concept step by step.

Why This Matters

Layer models are the fastest way to debug and communicate networking issues.

Confusion Busters

Common confusion: OSI is implementation

Fix: OSI is conceptual model; TCP/IP is practical stack used on internet.

Common confusion: Encapsulation direction

Fix: Sender goes down layers; receiver goes up layers.

OSI Basics

  • ▸7-layer conceptual model for communication and troubleshooting.
  • ▸Encapsulation and decapsulation explain packet transformation.

OSI 7-Layer Model

L7ApplicationHTTP, DNS, SMTP
L6PresentationTLS, MIME
L5SessionNetBIOS, RPC
L4TransportTCP, UDP
L3NetworkIP, ICMP
L2Data LinkEthernet, ARP
L1PhysicalCables, Radio

← Encapsulation (down) · Decapsulation (up) →

TCP/IP Basics

  • ▸Practical 4-layer internet communication model.
  • ▸Maps application needs to transport and internet routing.

OSI vs TCP/IP

TCP/IP

Application
Transport
Internet
Network Access

OSI (equiv.)

Application · Presentation · Session
Transport
Network
Data Link · Physical

OSI vs TCP/IP Quick Comparison

OSITCP/IPPrimary Function
Application + Presentation + SessionApplicationApp protocol and data formatting
TransportTransportEnd-to-end transport via TCP/UDP
NetworkInternetLogical addressing and routing
Data Link + PhysicalNetwork AccessFrame delivery and signaling