Networking
Beginner
What is OSI Model?
The seven-layer Open Systems Interconnection model that standardizes network communication functions from physical transmission to application protocols.
The OSI model divides networking into seven abstraction layers: Layer 1 Physical (cables, signals), Layer 2 Data Link (Ethernet frames, MAC addresses), Layer 3 Network (IP packets, routing), Layer 4 Transport (TCP/UDP segments, ports), Layer 5 Session (connection management), Layer 6 Presentation (encryption, compression), and Layer 7 Application (HTTP, DNS, SMTP). Each layer serves the layer above it and is served by the layer below. While the internet primarily follows the simpler TCP/IP model (4 layers), the OSI model remains the standard framework for discussing and troubleshooting network issues by layer.
