This is the logical structure of the layered protocols inside a computer on an internet. Each computer that can communicate using internet technology has such a logical structure. It is this logical structure that determines the behavior of the computer on the internet. The name of a unit of data that flows through an internet is dependent upon where it exists in the protocol stack. These definitions are imperfect.
Actual definitions vary from one publication to the next.
More specific definitions can be found in RFC 1122, section 1.3.3. A driver is software that communicates directly with the network interface hardware. A module is software that communicates with a driver, with network applications, or with another module. The terms driver, module, Ethernet frame, IP packet, UDP datagram, TCP message, and application message are used where appropriate throughout this tutorial. 2.3 Flow of Data Let's follow the data as it flows down through the protocol stack shown in Figure 1.