OSI Layers: Open Systems Interconnection model is a reference model developed by International Organization for Standardization in 1984, as a conceptual structure of principles for communication in the network across different applications by different vendors
Layer 7:Application Layer
Application layer interface to user processes for communication and data transfer in network. Provides consistent services such as virtual terminal, file and job transfer and operations
Layer 6:Presentation Layer
Masks the differences of data formats between different systems Specifies architecture-independent data transfer format Encodes and decodes data; Encrypts and decrypts data; Compresses and decompresses data
Layer 5:Session Layer
Important function of session layer are :
Dialog controller - Session layer is the dialog controller. it establishes, maintain and synchronizes between communicating system, token management- its also provide token management services
Layer 4:Transport Layer
Manages end-to-end message delivery in network Provides reliable and sequential packet delivery through error recovery and flow control mechanisms Provides connectionless oriented packet delivery
Layer 3:Network Layer
Determines how data are transferred between network devices Routes packets according to unique network device addresses Provides flow and congestion control to prevent network resource depletion
Layer 2:Data Link Layer
data link layer transforms the physical layer, row transmission facilities to a reliable link and its is responsible for node to node deliver also operating the communication links Frames packets Detects and corrects packets transmit errors
Layer 1:Physical Layer
Defines physical means of sending data over network devices. physical layer perform the functions required to transmit a bit stream over a physical medium