When deploying Nutanix unified Storage Objects.

S3 stands for simple storage service and it is a widely used object storage protocol that allows you to store and retrieve any amount of data from anywhere on the web. SMBv2 stands for server message block version 2and it is a file sharing protocol that enables access to files on remote servers. Nutanix Unified Storage Objects supports both S3 and SMBv2 protocols for data access.

https://next.nutanix.com/installation-configuration-23/ports-and-protocols-reference-chart-40249