16.7 PRESENTATION LAYER

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16.7 PRESENTATION LAYER

In computer networks, computers may be running different operating systems having varying file systems and file storage formats. For example, the file formats of Windows and Unix operating systems are different. Some computers may be using ASCII for character representation, and some computers may be using EBCDIC. Before exchanging the data for a file transfer, for instance, the two systems have to negotiate and agree on the format to be used for exchanging the data. This is done at the presentation layer. To provide secure communication, the data may need to be encrypted, which is also a part of this layer's job. Compression of the data for faster data transfer is also done in this layer. Hence, the functions of the presentation layer are:

• Provide for selection of data formats to be exchanged between applications

• Encryption

• Data compression

The functions of the presentation layer are negotiation of data formats, data encryption and data compression.

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