Which protocol family provides rapid convergence at Layer 2 to prevent outages after topology changes?

Which protocol family provides rapid convergence at Layer 2 to prevent outages after topology changes?

• A. BGP
• B. OSPF
• C. Spanning Tree Protocol variants such as RSTP/MSTP
• D. DNS

Answer: (C)

When a Layer 2 topology changes, you need a mechanism that quickly reconfigures the switch fabric to maintain a loop-free, forward-path structure and minimize downtime. The Spanning Tree Protocol family is designed for exactly this: it creates a loop-free topology by electing a root bridge and blocking redundant paths. Traditional STP can be slow to converge, but modern variants—Rapid Spanning Tree Protocol and Multiple Spanning Tree Protocol—converge much faster. RSTP speeds up transitions by allowing ports to move directly from blocking to forwarding as soon as a change is detected, while MSTP extends this idea across multiple VLANs with separate spanning trees to optimize convergence in large networks. In contrast, the other options operate at different layers or functions. BGP and OSPF are Layer 3 routing protocols that determine paths between networks, not how Layer 2 switches reconfigure after a topology change. DNS is a name resolution service and has no role in Layer 2 convergence.

When a Layer 2 topology changes, you need a mechanism that quickly reconfigures the switch fabric to maintain a loop-free, forward-path structure and minimize downtime. The Spanning Tree Protocol family is designed for exactly this: it creates a loop-free topology by electing a root bridge and blocking redundant paths. Traditional STP can be slow to converge, but modern variants—Rapid Spanning Tree Protocol and Multiple Spanning Tree Protocol—converge much faster. RSTP speeds up transitions by allowing ports to move directly from blocking to forwarding as soon as a change is detected, while MSTP extends this idea across multiple VLANs with separate spanning trees to optimize convergence in large networks.

In contrast, the other options operate at different layers or functions. BGP and OSPF are Layer 3 routing protocols that determine paths between networks, not how Layer 2 switches reconfigure after a topology change. DNS is a name resolution service and has no role in Layer 2 convergence.