This read-only INTEGER indicates whether a given interface's membership in a VSAN was determined statically, dynamically, or is unknown. An administrator reviewing VSAN membership uses this to understand whether a port's VSAN assignment comes from a fixed configuration or from dynamic WWN-based rules, which affects how to troubleshoot or change it. For example, an interface reported as dynamic tells the admin to look at the WWN dynamic mapping table rather than the static per-interface VSAN setting to change its membership.