The presentation layer performs certain functions that are
requested usually to look for a general answer for the user, rather than letting each user solve the problems.
In particular, unlike all the lower layers, which are just interested in moving bits reliably from here to there, the presentation
layer is concerned with the syntax (way it looks) and semantics(specifics) of the information being sent..
An example of a presentation service is preparing data in a way that is agreed on with both computers. Most user
programs do not share the random binary bit strings.( ths stuff that makes the program tick , or its language) They
exchange things such as people's names, dates, amounts of money, and invoices. These items are represented as character strings,
integers, floating point numbers, and data structures composed of several simpler items. Different computers have different
codes for showing character strings, integers and so on. In order to make it possible for computers with a different
way of sharing and communicating the data structures to be exchanged can be defined in an abstract way, along with a standard
encoding to be used "on the wire" (over the network). The job of managing these abstract data structures and changing
from the representation used inside the computer to the network standard representation is handled by the presentation layer.
The presentation layer is also concerned with other parts of information representation. For example, data compression
can be used here to reduce the number of bits(how big the file is) that have to be transmitted and cryptography(the type
of codeing) is frequently required for privacy and authentication.