How Does A OSI Model Works?Briefly Explain With An Example

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How Does A OSI Model Works?Briefly Explain With An Example

2 Answers

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Answer 1

Open Systems Interconnection model describes the hypothetical architecture for networks and provides a framework into which other standards and products should fit in.

OSI model is based on layered architecture where each layer plays a vital role in the overall communication effort and interacts with the other layers above and below it and also with the corresponding layer in the other network. It consists of seven layers namely from bottom to top; Physical Layer, Data Link Layer, Network Layer, Transport Layer, Session Layer, Presentation Layer and application Layer.

Suppose we have an application running on computer A producing some data to be transmitted to computer B then the flow of data transmission will be from Application layer of computer A to the Physical Layer of Computer A, along the physical network and then from Physical Layer of B to the Application Layer of B. Each layer does the following:

Physical Layer: This is non software layer and deals with physical connection between the network nodes.

Data Link Layer: This layer is responsible for the transmission of data packets

Network Layer: This layer is responsible for the routing of data packets

Transport Layer: This layers controls the correct delivery of packets and resends the packets in case of lost

Session Layer: This layer maintains the logical session between the two nodes

Presentation Layer: This layer resolves any data encoding between communicating nodes

Application Layer: This layers present data in full form to the user as delivered from sending node to the receiving node

Answer 2

OSI reference model serves as a guide for information exchange. This model divides communication task into seven sub tasks. A different layer handles each task. Layer is an abstraction for the services and protocols at some specific level. Layers are organized in a hierarchical fashion in such a way that a layer produces data and hands it over to the next layer that adds some data (header) or does some processing and transfers the data to the lower layer and in this way data travels through six different layers of OSI model and reaches the physical layer that transmits data in the form of signals and these signals are received by the physical layer at the destination computer. This data then moves up six layers and reaches the application layer in the format it was produced by the application layer in the source device. Following are the seven layers of OSI model:

1. Physical Layer
2. Data Link Layer
3. Network Layer
4. Transport Layer
5. Session Layer
6. Presentation Layer
7. Application Layer

These layers are arranged in the form of stack that means the layer in the source and destination computer work in the reverse order. The Layer that produces the data first in the source computer is the last one to receive that data on the destination device

Here is the explanation of it in the pic.