The Foundation of Everything

Layer 1 is where it all starts — the physical infrastructure that carries your network traffic. This layer deals with cables, connectors, network interface cards, and the raw transmission of bits.

Key concepts:

• Everything you can touch lives at Layer 1
• Electrical signals through copper, light pulses through fiber
• 80% of network problems are physical
• If Layer 1 fails, nothing above it can work

The Rule

Your physical infrastructure sets the ceiling for your entire network. Check Layer 1 first, every time.