This Recommendation describes high-level characteristics of network softwarization for non-radio part of IMT-2020. It explores network slicing from two viewpoints: vertical and horizontal aspects. After overviewing in each aspect@ the Recommendation further describes network slicing for mobile fronthaul/backhaul@ introduction to advanced data-plane programmability@ and capability exposure@ whose technical characteristic descriptions are expected to lead to their detailed study. The detailed technical features (e.g.@ signalling specifications) are out of the scope of this Recommendation.