The OSI Model For Students

The OSI model is divided into 7 layers. So when information comes from the network it moves UP the OSI model; Beginning at layer 1and proceeding to where the user actually interacts with the information at layer 7.

Each of these layers has its own purpose but also cooperates with their neighboring layers for the function of moving information from the network to the user and vice versa. “(2015, A. Anaya Ashe.)

I like to remember the layer as; Programmers Do Not Throw Sausage Pizza Away = Physical, Data Link, Network, Transport, Session, Presentation, Application.

The physical layer is anything that lets you see feel hear touch etc. the physical layer also includes but is not limited to things such as hubs, repeaters, and USB cables, because they simply take the electrical impulse and transmits and/or amplifies the signal.

The Data Link layer includes things such as network switches, it does more than transmit the information. A switch interacts with the information by reading the information into memory reconstructing it then transmitting it out. This layer also handles some errors and flow control.

The Network layer separates the information into packets and forwards these packets appropriately.

The Transport layer ensures the information moves and arrives reliably and also handles error checking and flow control.

The Session Layer is responsible for the “setting up and taking down of the association between two communicating end points” (n.d.)

Presentation Layer (or Pizza) is the translator. It presents the information to the application layer in a way the application understands and vice versa.

The Application layer is the layer that a person interacts with, such as GUIs or the Apps on your smartphone.

References        

Alexander. A. (2015) AIUOnline.edu U3 IP ITCO103 AIU

Session Layer. N.D. Techtarget.com retrieved from searchnetworking.techtarget.com/definition/Session-layer