Final answer:
Communication in a network is carried through a medium, which is the material substance that allows for the transmission of signals between devices.
Step-by-step explanation:
Communication in a network is carried via a medium. This medium can be any material substance that carries an electrical signal between the transmitter and the receiver in a network. Examples of mediums include twisted pair cables, fiber optic cables, or even air and space in the case of wireless communications. Devices like routers, controllers, and sensors are involved in the process of communication; routers manage the routing of data, controllers handle task management, and sensors detect and measure changes in the environment. However, they are not the medium through which communication signals are transmitted.