Cisco Certified Network Associate (CCNA) 2026 – 400 Free Practice Questions to Pass the Exam

The correct answer highlights that PVST+ and PVRST modify the STP (Spanning Tree Protocol) Bridge ID by incorporating the VLAN ID into the Bridge ID. This is significant because it allows the protocol to maintain separate spanning tree instances for each VLAN, thus enhancing network efficiency and segmentation.

In PVST+ (Per VLAN Spanning Tree Plus), for every VLAN that is configured, a unique Bridge ID is created which consists of the Bridge Priority (default is 32768), the VLAN identifier, and the MAC address of the switch. This means that if you have multiple VLANs, each VLAN will have its own spanning tree, enabling optimized traffic handling and reducing broadcast domains.

PVRST (Rapid Per VLAN Spanning Tree) operates similarly but is designed to offer faster convergence times compared to traditional STP. Both protocols uniquely utilize the VLAN information in the Bridge ID, distinguishing them from regular STP implementations, where the Bridge ID does not take VLANs into account.

The other options do not accurately describe how the Bridge ID modification occurs under these protocols.