OSI Model
Layer 1 - Physical Layer
This layer defines the physical means of transmitting data, such as the cables, connectors, and other hardware devices.
Layer 2 - Data Link Layer
This layer provides error-free transmission of data frames between nodes on the same local network.
Layer 3 - Network Layer
This layer handles the addressing and routing of data packets between different networks, including the Internet.
Layer 4 - Transport Layer
This layer provides reliable and efficient delivery of data between applications on different hosts.
Layer 5 - Session Layer
This layer manages the establishment, maintenance, and termination of sessions between applications.
Layer 6 - Presentation Layer
This layer is responsible for data translation and encryption, ensuring that data is in a format that the receiving application can understand.
Layer 7 - Application Layer
This layer provides access to network services for applications, including email, file transfer, and web browsing.
Layer 8 - User Layer
Layer 8 is not actually a part of the OSI model, but rather a tongue-in-cheek term used in the information technology industry to refer to the social and political issues that can affect technology decisions. It is a humorous way of saying that human beings are often the "missing layer" in technology discussions, and that their opinions, motivations, and biases can play a significant role in how technology is used and implemented. So, while layer 8 is not an official part of the OSI model, it is a reminder that the model is just a conceptual framework, and that there are many real-world factors that can influence how technology is actually used and adopted.