Membrane systems can be used to describe transfer of objects between different locations (membranes) and their eventual transformation. Network transmission protocols provide something similar, especially the transfer of data. In this paper, we describe the use of a membrane system for modeling data transmission between IoT devices, while it is possible to take this model as a generalization of the transmission operation transferable to other protocols or to various programming languages. The paper also discusses the possibility of using rules of the membrane system to create a simple firewall.