Spanning Tree Protocol Basics

Networks want redundant links for reliability but cannot tolerate the loops they create. Spanning Tree Protocol (STP) solves this. STP automatically detects redundant paths between switches and blocks just enough of them to leave a single loop-free path, while keeping the blocked links ready as backups. This lesson covers the basics of how STP prevents loops without sacrificing redundancy.

STP builds a logical tree with no loops on top of a physical network that may contain loops. It does this by choosing one path between any two points and disabling the rest. If the active path later fails, STP reactivates a blocked link to restore connectivity. So you get redundancy for resilience and a loop-free shape for safety at the same time.