The OSI model comprises multiple layers of architectural systems where each layer performs a defined function. Collectively, the different layers transmit data from one layer to another, with the layers generally classifiable into upper layers and lower layers. Generally, the OSI model is classified into three different layers (Lowe, 2016).
The physical layer – The OSI physical layer is designed to define the physical specifications of data. It establishes the relationship between the physical transmission media and the device involved in the communication process. The physical layer is not protocol-specific, and examples include physical network adaptors, ethernet connections, networking hubs, and repeaters (Lowe, 2016).
Data link layer – The data link layer is concerned with correcting errors that may occur at the physical layer level. It allows the networker to define protocols that establish a connection and terminate them between two connected network devices. The data link layer is IP-address-sensitive and helps establish logical frameworks, which allow the definition of endpoints within the communication. This layer also allows the routing of packets within the network and can be further categorized into two, including the media access control layer and the logical link control layer (Lowe, 2016).
Transport layer – The transport layer of the OSI model provides data transport from the source machine to the destination machine. Its role thereof is to maintain quality within the networking system and determines how much data needs to be sent to maintain error-free communication. The transport layer also helps to control different levels of communication, including flow control, error control, as well as facilitating segmentation and de segmentation. Lastly, the transport layer also ensures that the message is delivered directly to the destination machine without any errors (Lowe, 2016).