Presentation Layer (Layer 6)

The presentation layer of the OSI model sometime called conversion layer because when one computer sends data form one computer to another, the data is actually send in the form of stream of bits, they are 1’s and 0’s (on and off of the electrical signal ). When the receiving side receives that stream of bits it actually doesn’t know what kind of data it is (text, video, image, sound) until the data reach at the presentation layer.

At the sending side typically these function happens

   ·        Compression

   ·        Encryption

   ·        Data Formatting

At receiving side thing are opposite

   ·        Decompression

   ·        D-encryption

   ·        Data Formatting

These types of files that we need to do the above mention functions

   ·        ASCII (Alphabetic Text)

   ·        EBCIDC (Text Numbers)

   ·        JPEG, GIF, TIFF (Pictures)

   ·        MPEG (Video)