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Why Does the OSI Reference Model Matter?
OSI termed Open Systems Interconnect is developed in the year 1983 by ISO (International Organization for Standardization) professionals and it has been declared as an international standard of communicating through the network in later 1984. This model consists of seven layers of abstraction which are used for the transmission of data from a device through the channel to another device. Each layer is designed to do its task by getting data in the form of bits or packets and then forwarding the processed data to the upper layers in the architecture.
Architecture designed in the OSI model helps the network administrators to identify issues either in the software application or network channel and developers can also track the working of software designed at each stage and fix problems if raised. Vendors may inform the client on which layer their software or products function when any new product has been launched.
Layers of OSI Model
OSI model has 7 layers to transfer the data from the router or device attached to the network over a physical medium and reaches its destination device. The functions of each layer are discussed below to know the importance of data transmission. The first three layers are defined for hardware devices and the middle layer is the heart of the OSI model below three layers support software applications.
Physical Layer − Raw data that is obtained from the switch or hub will be of digital bits. These bits are converted into signals either radio or electrical and are transmitted through the physical medium between the sender and receiver. All the physical resources are included like routers, repeaters, modems, adapters, etc.
Data Link Layer − This layer is responsible for sending and receiving data frames to each node. Also provides error detection that is occurred at the physical layer.
Network Layer − Conversion of data frames into packets is done here. This layer includes the functions of addressing, routing, and internetworking.
Transport Layer − This layer transfers the data in the same order they are packed and ensure end to end delivery between source and destination using TCP or UDP protocols.
Session Layer − Creates a session for exchanging information between nodes. Synchronization and dialog control are the other functions of this layer.
Presentation Layer − This layer converts the data into a presentable form by verifying the syntax and semantics which includes encryption, compression, and translation techniques.
Application Layer − This is used for interaction between users and the application allowing access to the resources provided by the network.
Reasons for using the OSI model till date
Both OSI and TCP/IP model has their functionalities on data transmission; the OSI model has been used by many of the vendors for their software to support the entire layer in the stack that supports various technologies.
As it has a layered architecture, setup is easier for a generic model whereas TCP/IP is used for specific network protocols and devices so setting up factors is difficult here.
2. Protocol Dependency
TCP/IP is protocol dependent model, one should always rely on precise protocol standards for development purposes but OSI is an independent one where protocols can be implemented as per requirements. When the technology needs to be changed or updated then supporting protocols can be added at the layers desired.
3. Data Distribution
Each layer in OSI has different forms of data like bits, frames, and packets and all these forms of data should be transmitted from one level to the upper level in the OSI layer. The middle layer which is the transport layer takes care of this data transmission and delivery in a connection-oriented process through the network whereas, in TCP/IP, both connection-oriented and connectionless transmission is accepted so this does not guarantee delivery of exact data format.
4. Threat detection
OSI model monitors threat issues and issues like troubleshooting at the same layer where the threat has occurred. Categorization of threats is also made within each layer which is not provided by the TCP/IP model.
5. Security monitoring
Since each layer in OSI is data-oriented this helps to identify and keep track of security risks across the network. This provides a detailed way of representing data to get clarity on each level and vulnerabilities if detected.
6. Vendor Support
Developers are free to implement the hardware and the software needed at each layer to communicate over the network. New products developed can be tested at the client or user end by installing only needed interfaces that are supported to execute the application.
OSI model supports integration with various networks and frameworks for providing different services to customers. This feature can be used by the organization to build its hardware and software at each layer and execute it at different network domains.
Finally, the OSI model is a generic model proposed to communicate from one device to another in a secure and reliable path over the network. It helps in a better understanding of how data is transmitted at each layer with proper modularization and this helps developers to monitor the data flow till the user end.
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