In this chapter, we learned everything there is to know about the OSI network model. First, we learned about the governing bodies that defined the standard reference model, including when and why they set out to solve the problem of unified network modeling. Then, we took a close look at the model they defined, including looking at every layer in their stack, and what responsibilities entities in those layers assume. We learned about how protocols define standardized communication patterns for entities operating on the same level in the network stack, but on separate hosts on a network. We saw how service definitions allow entities to pass data through the network stack and deliver messages to remote entities.
We also took a close look at some of the most common communication protocols, which we'll be interacting with in the rest of this book. We started with the...
