Hybrid Model
In the real world, we use a mix of both the OSI model and the TCP/IP model, called the Hybrid model. In the Hybrid model, the Application layer is a combination of the Application, Presentation, and Session layers of the OSI model (similar to the TCP/IP model). The remaining layers. The transport Layer, Network Layer, Data Link Layer, and Physical Layer are the same as the OSI model.
OSI, TCP/IP and Hybrid Models
OSI Model is developed by International Organization for Standardization or ISO, the Open Systems Interconnection model or OSI model is a critical building block in networking. OSI Model helps in troubleshooting and understanding networks because of the layered approach that it follows. It consists of seven layers in which each layer has its functionality to perform.
Layers of OSI Model
These layers are given from bottom to up as below.
1. Physical Layer: Physical layer is the lowest layer in the OSI Model. This layer works on establishing actual physical connections among devices.
2. Data Link Layer: DLL works for the node-to-node delivery of the message.
3. Network Layer: The Network Layer is responsible for data transmission from one host to another located in multiple networks.
4. Transport Layer: The transport layer is responsible for message delivery across the points covered in the path to the destination.
5. Session Layer: The Session Layer works in the establishment, termination, and management sessions.
6. Presentation Layer: The presentation Layer has the work of encrypting and decryption data, and converting it to such form that can be accessed by Application Layer.
7. Application Layer: The application Layer is the topmost layer of the OSI Model, where the user interacts with the system.
Advantages of OSI Model
- Provides standards and interoperability.
- Split development(a person working in layer 3 need not be concerned with layer 7).
- Quicker development (as each layer is independent of the other, development in an OSI model is faster as compared to the old proprietary models).