(1) The facilities of a logical subsystem with which a host communicates when performing I/O operations to a single addressable unit over an I/O interface. The same logical device may be accessible over more than one I/O interface.
(2) A set of input or output operations for a physical or virtual device. For example, the Router logical device has logical device operations for creating a route and removing a route. Logical devices can be an abstraction of a physical device, such as a router, or virtual device, such as a software product.