OSI Characteristics

The Open Systems Interconnected (OSI) model is a concept that enumerates the networking of systems amount seven different layers. The seven layers within this model are essential because they help the organization visualize what is happening within their networks while simultaneously easing the work of programmers (Alani & Alani, 2014). In the modern generation, tech vendors often rely on this model to tell the customers the type of layer their products are engaged with. This paper will discuss the characteristics or functions of each layer within this model.

The Physical Layer

The physical layer forms the first layer of the model even though it is considered the last layer within the OSI model. The physical layer is tasked with preparing the physical gadgets in the network for data receipt. This layer can also function by terminating the link existing between two nodes connected to a network. The role of the physical layer is to take in raw data that goes to higher layers after some time. As such, it converts the digital bits into signals for proper communication in other layers of the model (Alani & Alani, 2014). Despite the above-enumerated characteristics, the physical layer performs different functions within the OSI model. For instance, the layer necessitates bit synchronization by utilizing a clock that regulates the sender’s and recipient’s information (Alani & Alani, 2014). Furthermore, it is the role of the physical layer to decide the topography type for node alignment within a network. Lastly, the physical layer controls the transmission rate in bits sent per second.

The Data Link Layer

The second layer, identified as the data link layer, allows the accessibility of the data by necessitating its breakdown into frames for more straightforward analysis. The breakdown of this data into bits ensures that the data is error-free and gets to the next layer on time (Fraihat, 2021). The data link layer sends the data it receives in packets. One of the distinguishing attributes of the data link layer from the other layers is that it is segmented into two sub-layers, namely the Logical Link Control and the Media Access Control Layer. The Logical Link Control transfers the bit of data to the next layer by locating the protocol code from the header (Fraihat, 2021). On the other hand, the Media Access Control Layer works by creating a connection to the network’s physical layer. This link necessitates receiving the receiver’s code through the utilization of the Address Resolution Protocol (Fraihat, 2021).

The data link layer performs various functions within the OSI model. First, this layer frames the data to make it meaningful to the end user through particular bit patterns. Additionally, the kit plays the role of the data link layer in controlling errors by detecting and retransmitting the frames. It also addresses the sender and receiver’s physical addresses in each frame. The other role the data link layer performs is determining the extent of regulation provided to a device within a given time and calculating the amount of data before its actual receipt (Briscoe, 2000). Lastly, the data link layer handles the proper functioning of the network interface card by regulating devices such as switches and bridges.

The Network Layer

The layer is bequeathed with the responsibility of transporting data from one node to another within the network. Since each layer is composed of a unique address, the network layer reads these addresses and sends the data to the required destination. The network layer’s other role is deciding the perfect route for information transportation from the source to the destination area through the routing process (Briscoe, 2000). Furthermore, it is the role of the network layer to break information into packets using the internet protocol and the formulation of connection between different devices in a layer.

The Transport Layer

The transport layer is the fourth layer that monitors the data, controls errors and initiates the process of segmentation or desegmentation. This layer is also segmented into the transmission control and user datagram protocols (Fraihat, 2021). The transmission control protocol divides the data into smaller segments that travel using different internet routes to arrive at their destination. In contrast, the user datagram protocol is the unreliable layer that does not receive any acknowledgment of the message during either receipt or upon sending.

The Session Layer

The fifth layer in this model is the session layer, which establishes a connection in this layer. The connection is established through managing, developing, and terminating existing remote and local applications. This layer quickly processes the connection’s establishment, utilization, and termination. It can also add checkpoints along the data pathways to act as synchronization points into the data for easier identification and avoidance of errors. The systems supported under the session layer work by interacting in either half-duplex or full-duplex (Fraihat, 2021).

The Presentation Layer

This layer works by converting the data into semantics that can be understood by an application quickly. The presentation layer formats the data through either compression or encryption, which is then sent to the other layers. The layer encrypts the data into a code as ciphertext and decrypts it back into plain text (Fraihat, 2021). The other functions the presentation layer performs include permitting the translation of functional languages from ASCII to EBCDIC and compressing the data into bits for easier transmission.

The Application Layer

As the last layer, the application layer provides the interface for users to engage with the data. The layer outlines appropriate communication parties that permit data transfer for applications such as browsers and messengers (Alani & Alani, 2014). The application layer works by permitting users to proceed with email forwarding and storage and allowing file storage and retrieval on the remote computer (Briscoe, 2000). The last function of the application layer is that it offers distributed database sources and global information regarding various objects.