Layering

Layering
Layering is a process of dividing into layers (The Free Dictionary. 2007). The architecture of modern network protocols is realized through layering. As the word suggests, the network protocols are constructed in a layered manner: one layer of functions is directly dependent and the previous layer while supporting the next one. In order for the network to work correctly, the layers have to correspond with each other without errors (Wikipedia. 2007). In 1977, although earlier models existed, //Open Systems Interconnection Basic Reference Model// was developed in an attempt to standardize the architecture of network protocols. This model, which became widely known as an excellent model for studying network protocols, included 7 layers of functions (Wikipedia. 2007):
 * 1) Physical layer
 * 2) Data link layer
 * 3) Network layer
 * 4) Transport layer
 * 5) Session layer
 * 6) Presentation layer
 * 7) Application layer

As described in the model, each of these layers serve to the layer in front and depend on the layer before them. For instance, Presentation layer encodes the received data and prepares it for the application layer, where already encoded data is ready to perform functions on the host computer (Wikipedia. 2007) The network protocols which are widely used today, such as TCP/IP (Wikipedia. 2007), use the layering models that include different number of layers, however, they are all essentially the same (Webopedia. 2007).

References: //Layer.// __==The Free Dictionary.==__ retrieved 14/9/2007 from [|.] //OSI model.// __==Wikipedia.==__ retrieved 14/9/2007 from [|.] //TCP/IP model.// retrieved 14/9/2007 from [|.] //OSI.// __**Webopedia .**__ retrieved 14/9/2007 from [|.]
 * __Wikipedia__ .**