How is connection between the devices excluded?

When communication is complete, the client sends a requestto the transmitter to end the connection.
Communication break between two operational end points:
The origin of the communication break can be the disconnection of the Ethernet cable on the Server side. The expected behavior is:
• If no packet is currently sent on the connection: The communication break will not be seen if it lasts less than the Keep Alive timer value. If the communication break lasts more than the Keep Alive timer value, an error is returned to the TCP Management layer that can reset the connection.
• If Some packets are sent before and after the disconnection: The TCP retransmission algorithms (Jacobson's, Karn's algorithms and exponential backoff. See section 4.3.2) are activated. This may lead to a stack TCP layer Reset of the Connection before the Keep Alive timer is over.
Crash and Reboot of the Server end point:
After the crash and Reboot of the Server, the connection is "half-open" on Client side. The expected behavior is:
• If no packet is sent on the half-open connection: The TCP half-open connection is seen opened from the Client side as long as the Keep Alive timer is not over. After that an error is returned to the TCP Management layer that can reset the connection.
• If some packets are sent on the half-open connection: The Server receives data on a connection that doesn't exist anymore. The stack TCP layer sends a Reset to close the half-open connection on the Client side.