In the OSI model, there are two types of layer interactions: adjacent layer and same-layer interaction.
Adjacent Layer Interaction
Refers to processes like encapsulation that involve direct interactions between adjacent layers of the OSI model.
Same-Layer Interaction
Refers to processes where one layer is interacting with the same layer in another machine or application. For example, in an instant messaging app, the interaction between the application layers on the sender’s machine and the receiver’s machine.