BROCADE IP PRIMER

The OSI Reference ModelEach of these layers represents a piece of the process. They each worktogether to achieve communication. Starting at the Application Layer, communicationflows this way:ApplicationPresentationSessionTransportNetworkData LinkPhysicalNotice that each layer only needs to be aware of its neighbor. This allows agreat deal of freedom. While a single manufacturer could certainly write a protocolstack that handles the work of all seven layers, they don't need to.Also, you can see from the diagram that communication flows from one layerto the next. This means that, for any given layer, they only need to be aware oftheir neighbors. For example, the Presentation Layer (Layer 6) does not needto know which Data Link (Layer 2) technology you're using. It only needs toknow how to deal with the data that the Application Layer sent it, and it needsto know how to interact with the Session Layer (Layer 5). Likewise, the TransportLayer needs to know how to interact with the Session Layer (Layer 5) andthe Network Layer (Layer 3). It never has to interact with any other layer.We know that data travels down through the layers to the Physical Layer (Layer1), but then what happens? Now, the data is sent to the remote computer. Butwhat does the remote computer do with it? Once again, it travels through thelayers of the OSI Reference Model, but this time, it travels in reverse.Brocade IP Primer 5