Networking / Beginners

The Session Layer

Layer 5 allows the user to create a session between the source and destination. One example is a remote login session: you make the session by using telnet or ssh or whatever and this session persists until you log out, when the session is taken down. Sometimes a session can be very short, e.g., just long enough for an email or Web page to be transmitted.

This layer takes care of things like synchronization: if you have a large file to transmit that takes 2 hours and the network or the remote machine crashes after 1 hour, the session layer can reestablish the connection at the point it left off rather than starting again. The session persists even if the transport disappears for a while.

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In this tutorial:

  1. Layering Models
  2. The Seven Layer Model
  3. The Physical Layer
  4. The Data Link Layer
  5. The Network Layer
  6. The Transport Layer
  7. The Session Layer
  8. The Presentation Layer
  9. The Application Layer
  10. How the Layers Fit Together
  11. Why Layers and Encapsulation?
  12. The Internet Model
  13. The Link Layer
  14. Models and Protocols
  15. Comparing OSI and Internet Models