Open System Interconnect model (OSI) When examining a complex model, it is the situations that are always important to break the condition into small parts that can be understood or that are easily manageable. This is what an organization called International Organization for Standardization did. It broke the communication process into small manageable units or layers, and each unit or layer represents similar functions that provide services to the layers above and request services from layers that are below (ITU-T, 2003). OSI is an acronym for Open System Interconnect model and was developed in the 1980s by the International Organization for Standardization (ISO). The OSI model consists of seven layers namely application, presentation, session, transport network, data link, and finally physical layer. Anything to be communicated like a message starts at the application layer with the top layer and moves down the OSI layers to the bottom layer which is the physical layer. As the message moves through these layers layer-specific information is added and this information is called headers. When the message reaches the receiving end, the headers are stripped or removed as the message travels from the bottom to the top of the layer. So, the sending end encapsulates the message, and the receiving end does de-encapsulation. This is the function of the OSI model (Lorentz, 2005). Now we are going to discuss each of these layers and state what they do during the process of encapsulation and de-encapsulation (ITU-T, 2003). The topmost layer called the application layer is involved in providing network services to the end-user applications. These services include file access, printing, mail transfer, and word processing. The next layer is called the presentation layer and determines how data is presented to the user. It provides services such as encryption, decryption compression, and decompression of the data. The next layer is the session layer (ITU-T, 2003). It is involved in establishing the connection and ending the connection between the communicating parties. For instance, two communicating mobile phones use a session layer to establish a connection. The fourth layer is called the transport layer and as its name signifies, it is involved in reliable data from the sending device to the receiving device. It is also involved in error detection and correction. The network layer is number three in the OSI reference model. It is involved in determining the most reliable route for the packet to pass through until it reaches its destination. The second layer is called the data link layer and this layer is divided into media access and logical link layer. The main purpose of this layer is to provide a means by which the message being sent can access the media. It also assists to identify the MAC address of the sending device. The first or the bottom-most layer is called the physical layer. Its function is mainly to receive and send raw bits. Bits mean 0s and 1s (Lorentz, 2005). This is because computers only understand binary, but they convert them to a manner in which human beings can understand. Communication Protocols Communication protocols can be defined as rules that communicating devices like computers or mobile phones follow to successfully communicate and understand the other partner on the other side (Holzmann, 2001). Since comp