Truths about OSI layers (Simple Method)

Hello friends, do you really confused about what is OSI actually works or not, I am revealed everything for you about OSI layers.

Actually, OSI layers is first introduced by the ISO (international standards organization) you can remember it by revers the OSI that is ISO. The OSI model is not a real-world model, it is just the conceptual model so you can only resemble it to the real situation at all but only think like the original.

OSI model was administered by the International Organization for Standardization (ISO) in 1970s and International Telegraph and Telephone Consultative Committee, or CCITT engaged in 1983 for this model but project is different. In 1983, these two documents were merged to form a standard called The Basic Reference Model for Open Systems Interconnection. OSI had two major components, an abstract model of networking, called the Basic Reference Model or seven-layer model, and a set of specific protocols. The concept of a seven-layer model was provided by the work of Charles Bachman at Honeywell Information Services.

OSI Layers: OSI have 7 layer

Layer 1 : Physical Layer

Layer 2 : Data link Layer

Layer 3: Network Layer

Layer 4: Transport Layer

Layer 5: Session Layer

Layer 6: Presentation Layer

Layer 7:Application Layer

New Layers Introduced:

Layer 8:individual
Layer 9:Organization
Layer 10:Government

The application layer is the OSI layer closest to the end user, which means both the OSI application layer and the user interact directly with the software application

The presentation layer establishes context between application-layer entities, in which the application-layer entities may use different syntax and semantics if the presentation service provides a mapping between them. If a mapping is available, presentation service data units are encapsulated into session protocol data units, and passed down the protocol stack.

The session layer controls the dialogues (connections) between computers. It establishes, manages and terminates the connections between the local and remote application. It provides for full-duplex, half-duplex, or simplex operation, and establishes checkpointing, adjournment, termination, and restart procedures.

The transport layer provides the functional and procedural means of transferring variable-length data sequences from a source to a destination host via one or more networks, while maintaining the quality of service functions

The network layer provides the functional and procedural means of transferring variable length data sequences (called datagrams) from one node to another connected to the same "network"

The data link layer provides node-to-node data transfer—a link between two directly connected nodes. It detects and possibly corrects errors that may occur in the physical layer.

The physical layer defines the electrical and physical specifications of the data connection. It defines the relationship between a device and a physical transmission medium (e.g., a copper or fiber optical cable, radio frequency). This includes the layout of pins, voltages, line impedance, cable specifications, signal timing and similar characteristics for connected devices and frequency (5 GHz or 2.4 GHz etc.) for wireless devices. 

Layer 8 is used to refer to "user" or "political" layer on top of the OSI model of computer networking

Layers 8, 9, and 10 are sometimes used to represent individuals, organizations, and governments for the user layer of Service Oriented Architectures.

References: https://en.wikipedia.org