At which OSI layer does STP operate?
- Data Link
Spanning Tree Protocol (STP) operates at the Data Link layer (Layer 2) of the OSI model.
Switches and bridges running the spanning-tree algorithm communicate by exchanging multicast messages called bridge protocol data units (BPDUs) at regular intervals. BPDUs are used to build and maintain the spanning tree, ensuring a stable loop-free topology.
BPDU exchange facilitates the following:
- Election of a root switch (only one per spanning tree)
- Election of a designated switch for each switched segment
- Removal of loops by placing redundant switch ports in a backup (non-forwarding) state
STP is implemented on bridges and switches in order to prevent loops in the network. STP should be used in situations where redundant links are used.
Layer 2 Technologies
Configure and verify spanning tree