Purpose of Spanning Tree Protocol (STP) in a switched LAN: What primary problem does STP solve in Ethernet networks with redundant links?

Introduction / Context:
Redundant Layer 2 paths are valuable for resiliency, but they introduce the risk of loops. Unlike routed networks that use TTL decrements and routing protocols, Layer 2 frames can circulate indefinitely, causing broadcast storms and MAC table instability. STP is designed to address this.

Given Data / Assumptions:

• Ethernet switches forward based on MAC tables and flood unknown/broadcast traffic.
• Redundant physical links may exist between switches.
• Goal: loop-free operation without manually disabling paths.

Concept / Approach:
STP elects a root bridge and prunes the topology logically, leaving one active path per segment. Root and designated ports forward, while redundant paths are blocked, preventing loops. Rapid and Multiple STP variants improve convergence and scalability while preserving the core objective.

Step-by-Step Solution:

Verification / Alternative check:
Topology diagrams with triangles of switches demonstrate that, after STP convergence, exactly one link in the triangle is placed in a blocking/discarding state to prevent loops.

Why Other Options Are Wrong:

• Network monitoring is unrelated to loop prevention.
• Routing loops are Layer 3 and handled by routing protocols, not STP.
• VLAN database management (e.g., VTP) is a different control plane task.
• Collision domains are defined by switch ports; STP does not create them.

Common Pitfalls:
Confusing STP with routing protocols; assuming link aggregation alone eliminates loops (it does not across topologies).

Final Answer:
Prevent switching loops in redundant Layer 2 topologies