OSI Model
Computers · OSI मॉडल · 15 facts
OSI Model has 7 layers for network communication
Layer 1: Physical — cables, signals, hardware
Layer 2: Data Link — MAC address, switches
Layer 3: Network — IP address, routing
Layer 4: Transport — TCP/UDP, port numbers
Layer 5: Session — manages communication sessions
Layer 6: Presentation — encryption, data formatting
Layer 7: Application — HTTP, FTP, SMTP, DNS
TCP/IP model has 4 layers (simplified version of OSI)
Router operates at Network Layer (Layer 3)
Switch operates at Data Link Layer (Layer 2)
Hub operates at Physical Layer (Layer 1)
Mnemonic for OSI layers: Please Do Not Throw Sausage Pizza Away
OSI model was developed by ISO (International Organization for Standardization)
Firewall operates at Network and Transport layers to filter traffic