Open Systems Interconnection (OSI) Model

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The Open Systems Interconnection (OSI) model breaks the data communication process into discrete layers.

• developed by International Organization for Standardization (ISO) to promote understanding of how components in a system work
• separates functions of hardware and software components into 7 discrete layers
• each layer performs a different group of task required for network communication
• is not a standard or specification
• serves as a functional guideline for designing network protocols, software, and appliances and for troubleshooting networks

Data Encapsulation

• Data Encapsulation and Decapsulation

OSI Layers

• OSI Layer 1 – Physical
• OSI Layer 2 – Data Link
• OSI Layer 3 – Network
• OSI Layer 4 – Transport
• OSI Layer 5 – Session
• OSI Layer 6 – Presentation
• OSI Layer 7 – Application