OSI Model (Open Systems Interconnection)
Published in 1984 by the International Organization for Standardization (IOS). Using as a teaching tool to describe Network Architecture.
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OSI model allows things to develop independent of other layers. Specific functionalities will be implement at a particular level.
OSI – Layer 7: Application
There are not programs, applications living in this layer, Application layer provides protocols, rules… to support actual applications that would be considered to be above the Application layer.
Application layer provides services to the user’s application
Services within the Application layer: file transfer, mail, web service, …
OSI – Layer 6: Presentation
Presentation layer provides services including data conversion, data compression, data encryption
Presentation layer ensures that data sent from sender application layer is readable at the receiver application layer.
Refers as translator makes the the data understandable when two systems communicate.
OSI – layer 5: Session
Session layer establishes, manages and terminates connection between two host
OSI – Layer 4: Transport
Deliver message to the destination, segmentation and reassembly data.
Responsibility for source to destination of the whole message
Manage communication between sender and receiver
OSI- Layer 3: Network
Responsible for sourse-to-destination delivery of packets
Using logical addresses (IP addresses) concept to deliver packet
Routing refers to network layer, find the best path to send the packets
OSI – layer 2: Data Link layer
Resposible for the exchange of frames between nodes
Using physical address
OSI – Layer 1: Physical layer
Physical layer identifies interface between network devices
Responsible for transfer bit over the physical medium
Refer as binary transmission
From layer 3 to layer 7, these layers implemented in software, layer 2 implemented both software and hardware, layer 1 implemented hardware.
Communication between layer and it counterparts when sending and receiving the data based on logical conversation.
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