Question

I need to prepare a presentation slide on Protocols, explaining what is it, giving example, mentioning 3 protocols of each layer and giving its function and example. Please I need it to be self explanatory.

Answer 1

Functions and Protocols

As layer six of the OSI model, the presentation layer is primarily responsible for managing two networking characteristics: protocol and architecture. Whereas, protocol defines a standard set of guidelines under which the network operates, the network's architecture determines what protocol applies.

As the translator, the presentation layer converts the data sent by the application layer of the transmitting node into an acceptable and compatible data format based on the applicable network protocol and architecture. Upon arrival at the receiving computer, the presentation layer translates the data into an acceptable format usable by the application layer. In other words, the presentation layer takes care of any issues occurring when transmitted data must be viewed in a format different from the original format.

As a functional part of the OSI model, the presentation layer performs a multitude of data conversion algorithms and character translation functions. The first function is:

• Character-Code Translation: Where the presentation layer translates from the American standard code for information interchange (ASCII) to the extended binary code decimal interchange code (EBCDIC).

The second function is:

• Data Conversion: This is where the presentation layer performs bit order reversal functions, converts CR (byte code for a carriage return) to CR/LF, (byte code for a carriage return with a line feed) and converts integer numbers to floating point numbers.

Third, the presentation layer is responsible for:

• Data Compression, by reducing the number of bits requiring transmission, which improves the data throughput.

The fourth function is:

• Data Encryption and Decryption: Encryption is needed for security purposes when sending data across networks. An encryption algorithm is used during transmission, while a decryption algorithm is used at the receiving node. Encryption and decryption typically involves the secure sockets layer (SSL) protocol, which has become more popular when used by the presentation layer.

The fifth function of the presentation layer is:

• Data Translation: Networks provide the capability of connecting different types of computers, servers and mainframes on the same network and may employ different character sets. The presentation layer is responsible for fixing any irregularities while making translations transparent between networked systems.