The Spanning Tree Protocol (STP) is a network protocol that ensures a loop-free topology for any bridged Ethernet local area network. The basic function of STP is to prevent bridge loops and the broadcast radiation that results from them. Spanning tree also allows a network design to include spare (redundant) links to provide automatic backup paths if an active link fails, without the danger of bridge loops, or the need for manual enabling/disabling of these backup links.

Spanning Tree Protocol (STP) is standardized as IEEE 802.1D. As the name suggests, it creates a spanning tree within a mesh network of connected layer-2 bridges (typically Ethernet switches), and disables those links that are not part of the spanning tree, leaving a single active path between any two network nodes.

It includes the following topics -

• Spanning Tree Protocol IEEE 80d and Need
• Spanning Tree Working and Convergence
• EtherChannel PortFast and STP Security
• Rapid STP IEEE 802_1w RSTP
• RSTP Link and Edge Types Port States Roles and Convergence
• STP Configuration and Verification
• Multiple STP Instances
• Port Costs Priority PortFast BPDU Guard EtherChannel and RSTP Configuration
• STP Troubleshooting