What is the primary distinguishing feature of MSTP compared to RSTP?

The primary distinguishing feature of Multiple Spanning Tree Protocol (MSTP) compared to Rapid Spanning Tree Protocol (RSTP) is that MSTP supports multiple VLANs by allowing multiple spanning tree instances. This capability means that MSTP can optimize the use of network resources by allowing different VLANs to be managed independently within the same network topology. Each VLAN can have its own spanning tree instance, which enables efficient traffic management and load balancing across the network.

In contrast, RSTP is designed to improve the convergence times of the original Spanning Tree Protocol but only provides a single spanning tree for all VLANs. This can lead to inefficiencies in the network configuration as all VLANs share the same tree, leading to potential bottlenecks.

Thus, MSTP's ability to manage multiple spanning trees allows for greater flexibility and control in a VLAN-rich environment, which is key for organizations that utilize multiple VLANs for different departments or services. This capability is what sets MSTP apart from RSTP and makes it a preferred choice for modern network designs that require scalability and improved resource utilization.