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wikipedia.org/wiki/OSI_model

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Posted by crouse

For details:

en.wikipedia.org/wiki/OSI_model

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Posted by sagitraz

OSI stands for open system interconnection & it consists of 7 layers are

Application layer: for user interface

Presentation layer: provides coding into 1s & 0s
encryption, compression

Session layer: provides authentication, permissions & session establishment

Transport layer: end to end control

Network layer: do network addressing & routing

Data Link layer: do error detection, flow control

Physical layer: for representing bits

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Posted by Hash007

The International Standards Organization (ISO) defined a seven-layer model to standardize networking processes. The Open Systems Interconnection (OSI) model facilitates the understanding of the complexities of networking by defining what happens at each step of the process.
The OSI model does not impose rules on network equipment manufacturers or protocol developers; rather, it sets guidelines for functions so that inter-vendor operability is possible and predictable.
Each of the seven layers in the model communicates with the layers above and below, using standardized coding at the beginning of the message that can be interpreted by another device regardless of who made it. So if a vendor decides that they want to build a network device, they have the option of building a completely unique, proprietary system and trying to convince people to buy it; or, they can build a device that works with other devices according to the OSI model.
The seven different layers break up the process of networking, making it easier to understand and to troubleshoot problems. It is possible to test the functionality of each layer in sequence, to determine where the problem is and where to begin repairs.

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Posted by thomas