Overview
Spanning Tree Protocol (STP), standardized as IEEE 802.1D, prevents 'broadcast storms' and MAC table instability caused by physical loops in a switched network.
How it Works
- Elect a Root Bridge: The switch with the lowest Bridge ID.
- Select Root Ports: The best path from each non-root switch to the Root Bridge.
- Select Designated Ports: The port on each segment that forwards traffic toward the Root Bridge.
- Block Redundant Ports: All other ports are placed in a blocking state.
Port States
Blocking, Listening, Learning, Forwarding, and Disabled.