Organisational communication describes the official communication done by the organisation (here: within the organisation itself). Very often it is referred to as "communication 1.0" or "top-down communication".
According to Wikipedia (en) organisational communication
... is a subfield of the larger discipline of communication studies. Organizational communication, as a field, is the consideration, analysis, and criticism of the role of communication in organizational contexts. Its main function is to inform, persuade and promote goodwill. The flow of communication could be either formal or informal. Communication flowing through formal channel's are downward, horizontal and upward whereas communication through informal channel are generally termed as grapevine.