Spanning Tree Protocol (STP)
Spanning Tree Protocol prevents loops in switched Ethernet networks by blocking redundant links until they are needed.
What is Spanning Tree Protocol (STP)?
Loops in a layer 2 network cause broadcast storms that can bring it down. STP switches exchange bridge protocol data units (BPDUs), elect a root bridge and disable links that would form loops, re-enabling them if an active link fails. Rapid STP (RSTP) recovers much faster.