What is true regarding Spanning-Tree on AOS-CX switches at factory default?

The correct answer highlights the default behavior of Spanning Tree Protocol (STP) settings based on the model of the AOS-CX switches. For the 6200, 6300, and 6400 switch series, it is true that Spanning-Tree is enabled by default. This ensures loop prevention in typical network environments where these switches are deployed.

On the other hand, for the 8320, 8325, and 8400 switch models, the default is to have Spanning-Tree disabled. This design choice can be attributed to the advanced network requirements and configurations that these higher-end models are typically used for, where users often implement alternative methods for loop management or may prefer to configure STP as needed based on their specific network architecture.

Understanding these defaults is crucial for network administrators, as it helps them effectively plan and configure network topologies, especially when integrating switches of different models into a single network. This awareness of default settings also aids in troubleshooting network issues related to topology changes or redundancy configurations.