Introduction
This article describes the Rapid per VLAN Spanning Tree Protocol (Rapid PVST +) synchronization process based on Proposal / Agreement messages. The purpose of the synchronization is to form a new loop-free layer 2 topology as a response to changes in stable STP domains. The synchronization process is started by a switch that loses its connection to a current STP root switch and it does not have an STP Alternate port.
The article also describes the topology change process that occurs when the STP non-Edge port status changes from Discarding/Learning state to Forwarding state.
The idea for writing this article started when I studied the new Cisco VXLAN-based Campus Fabric model and I wanted to compare its complexity with the complexity of the traditional Campus network.
Figure 1-1: Spanning Tree topology
