OSI & TCP/IP Reference Models
Comparing theoretical 7-layer OSI stack vs 4-layer TCP/IP suite, protocol headers, PDUs, and live encapsulation mechanics.
1. Interactive OSI Encapsulation & Decapsulation Simulator
2. 7-Layer OSI vs. 4-Layer TCP/IP Architecture
ISO Standard
OSI 7-Layer Reference Model
7. Application LayerData
6. Presentation LayerData
5. Session LayerData
4. Transport LayerSegment
3. Network LayerPacket
2. Data Link LayerFrame
1. Physical LayerBits
Practical Internet Suite
TCP/IP 4-Layer Suite
4. Application (HTTP, SMTP, DNS, SSH)Data
3. Transport (TCP, UDP, Ports)Segment
2. Internet (IP, ICMP, ARP, Routers)Packet
1. Network Access (Ethernet, Wi-Fi, MAC)Frame/Bits
3. Interactive TCP 3-Way Handshake Connection Simulator
💡 Exam Key Concept: PDU Transformation Order
During transmission down the OSI stack, raw application data receives control headers at each step: Data $\rightarrow$ Segment (Transport) $\rightarrow$ Packet (Network) $\rightarrow$ Frame (Data Link) $\rightarrow$ Bits (Physical). On arrival, the receiver strips off headers in reverse order (Decapsulation).