OSI Seven Layer Model

See Protocol Layers:

The Open System Interconnection (OSI) Standard uses the following layers:

  1. Physical Layer (layer 1)
    1. Defines what high-low means (for 0 or 1)
  2. Data Link Layer (layer 2)
    1. Responsible for getting the data across one hop
    2. Error detection, error correction, flow control, and framing (grouping the data plus the layer 2 header)
  3. Network Layer (layer 3)
    1. Routes (picks the path across the network (depends on the network), picks the outgoing link)
  4. Transport Layer (layer 4)
    1. Operates end-to-end (considering the whole network)
    2. Handshake Protocol (Connection Oriented)
    3. Error Detection, error correction, flow control (so it does it at the very end, once we've reached the device we needed to)
    4. Reliable connection
  5. Session Layer (layer 5) (supports user connections, authentication)
  6. Presentation Layer (layer 6) (provides general solutions to common requests, like encryption, compression)
  7. Application Layer (layer 7) (provides access for users and applications)

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