We usually never try to think on the communication system and how it actually works at root level.
We are so surrounded with communication systems that personally I feel it has become 4 basic need
of human being. It sounds bit boring to read and learn or can say study. But I feel as a user of this system
I would brief out one model know as OSI model of communication system.
The Open Systems Interconnection model (OSI) is a conceptual model that characterizes and standardizes the internal functions of a communication system by partitioning it into abstraction layers. The recommendation X.200 describes seven layers, labeled 1 to 7. Layer 1 is the lowest layer in this model.
The internal data communication between this layers can be describe by below diagram.
Layer 1: physical layer
It 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). This includes the layout of pins, voltages, line impedance, cable specifications, signal timing, hubs, repeaters, network adapters, host bus adapters (HBA used in storage area networks) and more.It defines the protocol to establish and terminate a connection between two directly connected nodes over a communications medium.
Layer 2: data link layer
The data link layer provides node-to-node data transfer -- a reliable link between two directly connected nodes, by detecting and possibly correcting errors that may occur in the physical layer. The data link layer is divided into two sublayers:
Media Access Control (MAC) layer - responsible for controlling how devices in a network gain access to data and permission to transmit it.
Logical Link Control (LLC) layer - controls error checking and packet synchronization.
Layer 3: network layer
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. It translates logical network address into physical machine address.
Layer 4: transport layer
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 transport layer controls the reliability of a given link through flow control, segmentation/desegmentation, and error control.
Layer 5: session layer
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.
Layer 6: presentation layer
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 big mapping between them.This layer provides independence from data representation (e.g., encryption) by translating between application and network formats. The presentation layer transforms data into the form that the application accepts. This layer formats and encrypts data to be sent across a network.
Layer 7: application layer
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. This layer interacts with software applications that implement a communicating component.
We are so surrounded with communication systems that personally I feel it has become 4 basic need
of human being. It sounds bit boring to read and learn or can say study. But I feel as a user of this system
I would brief out one model know as OSI model of communication system.
The Open Systems Interconnection model (OSI) is a conceptual model that characterizes and standardizes the internal functions of a communication system by partitioning it into abstraction layers. The recommendation X.200 describes seven layers, labeled 1 to 7. Layer 1 is the lowest layer in this model.
The internal data communication between this layers can be describe by below diagram.
Layer 1: physical layer
It 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). This includes the layout of pins, voltages, line impedance, cable specifications, signal timing, hubs, repeaters, network adapters, host bus adapters (HBA used in storage area networks) and more.It defines the protocol to establish and terminate a connection between two directly connected nodes over a communications medium.
Layer 2: data link layer
The data link layer provides node-to-node data transfer -- a reliable link between two directly connected nodes, by detecting and possibly correcting errors that may occur in the physical layer. The data link layer is divided into two sublayers:
Media Access Control (MAC) layer - responsible for controlling how devices in a network gain access to data and permission to transmit it.
Logical Link Control (LLC) layer - controls error checking and packet synchronization.
Layer 3: network layer
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. It translates logical network address into physical machine address.
Layer 4: transport layer
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 transport layer controls the reliability of a given link through flow control, segmentation/desegmentation, and error control.
Layer 5: session layer
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.
Layer 6: presentation layer
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 big mapping between them.This layer provides independence from data representation (e.g., encryption) by translating between application and network formats. The presentation layer transforms data into the form that the application accepts. This layer formats and encrypts data to be sent across a network.
Layer 7: application layer
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. This layer interacts with software applications that implement a communicating component.
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