This object represents the Sync entity's selection mode. If this mode is configured as ql-mode, the selection of which reference should be used shall be based upon the reference's Quality Level. The highest received Quality Level shall be the selected reference. The priority shall only be used to distinguish between references with the same received QL. When multiple references have the same QL and same priority, the behavior of selection process within the group is non-revertive. If this mode is configued as priority-mode, the selection of which reference should be used shall be based upon the reference's priority (i.e. QL is disabled). When multiple references have the same priority, the behavior of selection process within the group is non-revertive.