What is a requirement for hosts to be attached to a distributed switch in vSphere?

The requirement for hosts to be attached to a distributed switch in vSphere is that they must have an Enterprise Plus license or belong to a vSAN cluster. The distributed switch is a more advanced networking feature available only in the Enterprise Plus edition of vSphere. This license grants access to additional networking capabilities such as port mirroring, NetFlow, and more complex network configurations that are not available in the lower-tier licenses.

Moreover, when hosts are part of a vSAN cluster, they can benefit from features integrated with vSAN, such as improved network performance and simplified management, which aligns with the advanced capabilities offered by a distributed switch.

Other options, such as the requirement for hosts to belong to a standard cluster or to only use SSD storage, do not accurately reflect the licensing or architectural prerequisites for utilizing a distributed switch. The statement that all hosts must be powered on is also incorrect because a host does not need to be powered on to be connected to a distributed switch; a powered-off host can still be part of the network configuration. Thus, the correct understanding centers on licensing and cluster capabilities specific to the distributed switch features within vSphere.