STP Multiple Versions in Production Network

In network configurations, it is generally advisable to use only a single Spanning Tree Protocol (STP) to avoid compatibility and complexity issues. However, situations may arise where both Per-VLAN Spanning Tree Plus (PVST+) and Multiple Spanning Tree Protocol (MST) are configured within the same topology. Such configurations are typically a result of necessity rather than design. This scenario often occurs during the merging of networks from different sites or significant network reorganizations. Ideally, this should be a temporary setup until a uniform network structure can be established.

When deciding on the root bridge in a network, regardless of the STP protocol used, the switch with the most stable and central connection to the network should be chosen. This is because the root bridge plays a crucial role in directing network traffic. The choice of protocol — MST or PVST+ — is less important than ensuring that the topological criteria for selecting the root bridge are met. Therefore, the configuration depends on specific network design and requirements rather than a preference for one protocol over the other.