This paper will discuss and describe the 7 layers of the Open System Interconnection model (OSI model) and the layers of the Transport Control Protocol/Internet Protocol model (TCP/IP model), and explain the similarities and differences of each model.
The 7 layers of the OSI model consist of: The Application layer (layer 7), The Presentation layer (layer 6), The Session layer (layer 5), The Transport layer (layer 4), The Network layer ( layer 3), The Data Link layer (layer 2) and The Physical layer (layer 1). All 7 layers together is referred to as the “Stack”, when data is transmitted it begins at the “Application” layer and end in the “Physical” layer.
Here is a description of each layer of the OSI model in order from highest to lowest. The easiest way to remember the layers is my memorizing the following “ All People Seem To Need Data Processing”. The 7 layers are:
The Application layer –
The Application Layer is the top layer of the OSI model. It provides a set of interfaces for applications to obtain access to networked services as well as access to the network services that support applications.
The Presentation layer -
The Presentation Layer handles data format information for networked communications. This is done by converting data into a generic format that could be understood by both sides.
The Session layer –
The Session layer allows two parties to hold ongoing communications called a session over a network. This comes into play at the beginning and end of data transmission. This layer also manages errors that occur in the upper layers, such as a low memory or low disk space.
References: Wikipedia Foundation Inc. (Sept. 2008) Retrieved 09/06/08 from http://en.wikipedia.org/wiki/Internet_Protocol_Suite http://en.wikipedia.org/wiki/OSI_Model Twiggs. W ( Dec 2000) Open System Interconnection – An Introduction to the OSI Model and Layered Communications. Retrieved 09/07/08 from http://www.comtest.com/tutorials/osi.html