OSI Model Flashcards
What is an OSI model?
The Open Systems Interconnection model, or OSI model, The OSI model is a theoretical model that explains how data travels from one device to another over a network. It separates the communication process into smaller parts or layers, which makes it easier to understand specific aspects of data transmission. And it also makes sure that communication between computers is set up in a consistent and efficient way.
Introduced in 1978, the OSI model describes networking as a series of protocol layers with specific functions allocated to each layer. Each layer offers specific services to higher layers, while hiding the details of the implementation of those services. A well defined interface between each pair of adjacent layers defines the services offered by the lower layer to the higher one and how those services are accessed.
The OSI model consists of seven unique layers, each with a specific role. From the bottom, the OSI model has a physical layer, data link layer, network layer, transport layer, session layer, presentation layer, and an application layer.
What are the 7 layers of the OSI model?
The bottom layer, or the physical layer, converts the data into wireless or electrical signals for transmission through the air or through cables. The next layer, the data link layer, ensures that the data is ready for transmission by making sure it is reliable and error free. The network layer selects the best path to route data packets over a network and addresses devices with the IPv4 and IPv6 protocols. Then the transport layer establishes connections between devices and can ensure reliable transport between the two. The fifth layer, the session layer, is responsible for managing communication sessions or states between applications. Next up, the presentation layer’s role is quite interesting since it deals with data formatting, encryption, decryption, and data presentation. And the final layer, or the application layer, plays an essential role by enabling the users or devices to communicate with each other. This layer provides an interface with which you can access the network to perform the necessary tasks.
What are the disadvantage to OSI model?
Because of the theoretical nature of the OSI model, it’s mostly used for educational purposes and may not always match how networks are set up in real lifeAnother disadvantage is that by breaking down the functions of a network into seven layers, it adds some extra steps which can slow down the speed of data transmission. Lastly, implementing the OSI model involves a lot of planning and hard work and can therefore be time consuming.
