Presentation Layer

The Presentation Layer (layer 6) follows, and is responsible for how information is represented while it's being transferred between Application Layer entities. This method of data representation is called the transfer syntax. Remember that lower layers in the protocol stack provide services to upper layers in the stack. In this case, the Presentation Layer makes a set of transfer syntaxes, which are available to the Application Layer. This layer therefore provides services such as encryption (ensuring that data is not easily readable while being transferred), decryption (making the data readable again), and translation of data between different structures. One protocol that exists at this layer is the X.216 protocol (the presentation service).