In the present paper, we consider a model that can be described as a “users – network applications” in local networks. The characteristic scales of the model are: the number of users up to 1024, time of events from several seconds to hours, the transmitted data volume –10-10000Kb. This scale rise to a new model that appears between the packet-level and the global Internet level models. We introduce the no-tion of the elementary data flow from an Internet service and from a peer. By using these notions, we develop the “metrology” approach to the modeling of data flow in local networks. Examples are present-ed.