What is the primary purpose of Spanning Tree Protocol (STP) in Layer 2 networks?

• A. To speed up data transmission.
• B. To prevent network loops in Layer 2 networks by disabling redundant paths.
• C. To route between VLANs.
• D. To assign IP addresses.

Answer: (B)

Spanning Tree Protocol is about preventing loops in Layer 2 networks by disabling redundant paths, creating a loop-free topology. In networks with multiple switches and interconnected links, frames can circulate endlessly and cause broadcast storms if loops exist. STP designates a root bridge and then selects which ports will forward traffic on each segment (designated ports) and which ports should stay blocked to break cycles. This arrangement leaves a single active path between any two devices while keeping backup paths available to quickly react if a link or switch fails, restoring connectivity through convergence. It’s not meant to speed up data transmission—convergence can briefly slow traffic as the topology recalculates. It also doesn’t handle routing between VLANs or assign IP addresses; those are functions of Layer 3 routing or DHCP, not Spanning Tree Protocol.