Layer 6 of OSI model known as OSI Presentation layer has three main functions such:
• Conversion and coding of application layer data to ensure data from the source host can be interpreted by the suitable application on the destination host.
• Encryption and decryption of data for transmission.
• Compression at the source host and decompression at the destination host.
Examples of OSI presentation layer are the standard for videos and graphics. Mostly used standards for video such Motion Picture Experts Group (MPEG) and QuickTime. MPEG is a methodology standard for video compression and coding. QuickTime is an Apple computer standard for video and audio. Mostly used standards for graphic images are Graphics Interchange Format (GIF), Join Photographic Expert Group (JPEG) and Tagged Image File Format (TIFF). JPEG and GIF are the standard for graphic images compression and coding, and TIFF is a standard coding format for graphic images.