On the other hand, the majority of computer systems use a lower number of layers than what is required by the OSI model. Why not use a smaller number of layers? What are some of the possible downsides associated with using fewer layers?
The OSI layer model is known as (Open Systems Interconnection Model). The OSI model is a conceptual framework used to describe the functioning of computer network systems. OSI model is a pair of 7 different layers from which every layer consists of a set of protocols that are useful in the support interoperability between different computer products and software.
The typical computer system uses the TCP/IP Model which consists of only 4 layers and has a smaller number of layers as compared to the OSI model.
The OSI model in reality is theoretical, and it has never been implemented in a computer system. The smaller number of layers is useful in implementing and understanding as compared to the seven layers of an OSI model As compared to the TCP/IP model, the OSI model does not have a special mechanism to provide stable and secure data connection.
The TCP/IP model is a protocol-oriented standard.
On the other hand, the TCP/IP model provides features such as the 3-way handshake mechanism, which provides a mechanism to establish a secure and reliable link over the network, so it is implemented on modern computers and not the OSI model.
The main possible downside associated with using fewer layers TCP/IP model is that In TCP, there is no clear distinction between services, interfaces, and protocols. Therefore, it is not a good idea to describe a new technology in a new network. It does not differentiate between data link and physical layers, which have very different functions.