Which protocol uses multiple STP instances to map VLANs to instances for scalable loop avoidance?

Which protocol uses multiple STP instances to map VLANs to instances for scalable loop avoidance?

• A. STP
• B. MSTP
• C. RSTP
• D. PVST+

Answer: (B)

Multiple Spanning Tree Protocol (MSTP) uses multiple spanning-tree instances to map VLANs to specific instances for scalable loop avoidance. In MSTP, each network region runs an Internal Spanning Tree (IST) plus several additional spanning-tree instances called MSTIs. VLANs are grouped and mapped to these MSTIs, so different sets of VLANs can use different active paths while still staying free of loops across the entire fabric. This mapping lets a large network limit the number of separate STP instances it must manage, improving scalability and convergence. Other protocols don’t offer this same approach. STP provides a single spanning tree for all VLANs, which becomes unwieldy as networks grow. RSTP speeds up convergence but still maintains one topology. PVST+ creates a separate spanning tree per VLAN, which can explode in size and complexity in large networks, whereas MSTP consolidates control by mapping VLANs to a finite number of MSTIs within an MST region.

Multiple Spanning Tree Protocol (MSTP) uses multiple spanning-tree instances to map VLANs to specific instances for scalable loop avoidance. In MSTP, each network region runs an Internal Spanning Tree (IST) plus several additional spanning-tree instances called MSTIs. VLANs are grouped and mapped to these MSTIs, so different sets of VLANs can use different active paths while still staying free of loops across the entire fabric. This mapping lets a large network limit the number of separate STP instances it must manage, improving scalability and convergence.

Other protocols don’t offer this same approach. STP provides a single spanning tree for all VLANs, which becomes unwieldy as networks grow. RSTP speeds up convergence but still maintains one topology. PVST+ creates a separate spanning tree per VLAN, which can explode in size and complexity in large networks, whereas MSTP consolidates control by mapping VLANs to a finite number of MSTIs within an MST region.