OSI Model Introduction
Layer 1 - Physical
Layer 2 - Data Link
Layer 3 - Network
Layer 4 - Transport
Layer 5 - Session
💡 NOTE: Cantrill does not have dedicated lectures on Layers 6 & 7. He has other lectures where he shows those layers implemented (e.g. SSL/TLS lecture for HTTPS). I might at some point include some basic info of those layers in these notes.