@MrAmazin91 Adjacent-layer interaction:
Adjacent-layer interaction occurs on one computer, with two adjacent layers in the model. The higher layer requests services from the next lower layer, and the lower layer provides the services to the next higher layer.

@MrAmazin91 Same-layer interaction occurs on multiple computers. The functions defined by that layer typically need to be accomplished by multiple computers—for example, the sender setting a sequence number for a segment and the receiver acknowledging receipt of that segment.

@MrAmazin91 A single layer defines that process, but the implementation of that layer on multiple devices is required to accomplish the function.

@MrAmazin91 The OSI Model (Open Systems Interconnection Model) is a conceptual framework used to describe the functions of a networking system.

@MrAmazin91 The OSI model characterizes computing functions into a universal set of rules and requirements in order to support interoperability between different products and software.