Rack Cabinets and Open Frame Racks. Rack Enclosures. Organize and secure networking, storage and telecom equipment in data centers, server rooms and network closets. A network-attached storage (NAS) enclosure is a storage device that provides hard disk drive (HDD) capacity to devices connected to a network. That means a NAS enclosure has the potential to be a low-cost storage option if commodity HDDs are used.