Advantages and Disadvantages of 7 Layers OSI Reference Model

For more than 35 years, the OSI reference model is guiding developers and vendors, facilitating a clear framework to describe the various functions of networking. ISO has divided it into seven different layers, with each layer having its separate functionality or work, which on completion transfers data to the next layers. As in any innovative model, there are advantages and disadvantages of 7 Layers OSI reference model.

Purpose of the OSI reference model

OSI reference model was developed in 1986 to overcome the disadvantage of communication among different operating platforms from various networks. The primary purpose of it is to process the communication between two devices working on two different platforms

7 layers of the OSI reference model

OSI or Open System Interconnection refers to a model that acknowledges how the applications transfer data across many types of computer systems or the network. ISO or the International Standard Organization developed the OSI model and divided it into seven layers, and each layer serves to the upper layer. The layers 1 – 4 are the lower layers for the host, and 5 – 7 are the upper layers that contain application-level data are for networking. This seven-layer OSI model architecture indicates the protocols of its use to exchange data between users in a network.

Advantages and disadvantages of OSI reference model

Like all models, there are some advantages and disadvantages of 7 layer OSI reference model which includes:

7 advantages of OSI reference model

1. Being a real generic model it is the standard model in computer networking and a guidance tool for developing any network
2. All its layers are distinguished as per their services, interfaces, and protocols
3. It can implement all protocols as they are hidden and has the flexibility to adapt to a lot of protocols
4. As it supports both connection-oriented and connectionless oriented it is possible to use it for reliability and quicker data transmission respectively
5. Since it follows the technique of divide and rule, it distinguishes services in different layers to make administration and maintenance easy and straightforward
6. Due to the layered architecture following the abstraction principle, the change occurring in one layer does not impact on the others
7. Provides more security and adaptability unlike having all services bundled together into a single layer

7 disadvantages of OSI reference model

1. Being a theoretical model, it restricts practical implementation as it does not consider any appropriate technology availability
2. As it does not define any particular protocol and invented before defining any protocols, it isn't very easy sometimes to fit in a new protocol
3. Being a complex model its initial implementation is slow, costly and cumbersome
4. Out of the seven layers, the session layer for session management and presentation layer for user interaction are with minimum functionality during practical deployment and hence are not as useful as the other five layers
5. The implementation of TCP/IP protocols were before the launch of this model, and therefore many organizations are reluctant for using it
6. There are duplication of services like addressing, flow control and among layers and in particular error control mechanisms in both the transport and link layer
7. Due to the interdependence among the layers, they cannot work parallel, and there is a need for waiting for receiving data from one after the other

The above advantages and disadvantages of 7 layers OSI reference model will help to implement it in organizations.