What does STP stand for?

• A. Spanning Tree Protocol
• B. Security Transport Protocol
• C. Simple Transfer Protocol
• D. Stream Transfer Protocol

Answer: (A)

Spanning Tree Protocol prevents network loops in Ethernet switching by building a loop-free topology. When a network has redundant paths, loops can cause broadcast storms and duplicate frames. STP uses Bridge Protocol Data Units to elect a root bridge (the switch with the lowest Bridge ID). From there, each non-root switch selects its root port—the port that offers the best path to the root—and other ports become designated ports on their segments. Redundant or conflicting paths are put into a blocking state, ensuring there is a single active path between any two devices. This keeps the network stable and prevents cycles. STP is defined in IEEE 802.1D, with faster variants like Rapid Spanning Tree Protocol for quicker convergence. The other terms don’t relate to loop prevention in Ethernet switching.