Explain the OSI model. What layers there are? What each layer is responsible for?

• Application: user end (HTTP is here)
• Presentation: establishes context between application-layer entities (Encryption is here)
• Session: establishes, manages, and terminates the connections
• Transport: transfers variable-length data sequences from a source to a destination host (TCP & UDP are here)
• Network: transfers datagrams from one network to another (IP is here)
• Data link: provides a link between two directly connected nodes (MAC is here)
• Physical: the electrical and physical spec of the data connection (Bits are here)

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