What is indicated if a boundary interface status appears broken?

When a boundary interface status appears as broken, it indicates that there is a discrepancy in the Spanning Tree Protocol configuration between PVST+ (Per VLAN Spanning Tree Plus) and MST (Multiple Spanning Tree). This situation arises typically when the two protocols are running on switches that are part of the same network but have been misconfigured, leading to an incompatibility regarding the port role assignments.

In the context of Spanning Tree protocols, if PVST+ is active on one side of the boundary while MST is operating on the other, there may be an inconsistency in how the ports are understood and managed by the two protocols. This misunderstanding results in the realization of a "broken" boundary interface, indicating that the communication about the Spanning Tree roles (such as root port, designated port, etc.) is not in agreement, leading to potential loops or connectivity issues.

The other options may be true in different contexts but do not accurately describe the condition that a broken boundary interface signifies in a Spanning Tree scenario. It is essential to ensure consistent configurations across different switches using either PVST+ or MST or establish clear conversion and compatibility strategies between the two to avoid such a status.