7.2.2 Close Connection - Hitachi HIDIC EH-150 Applications Manual

7.2.2 Close connection

The procedure for closing connection is shown as Figure 7.2.2.1.
Host PC
(A-2)
(A-3)
(A). In case EH-ETH requests to close connection
(A). In case EH-ETH requests to close connection
(A-
EH-ETH requests to close connection to the host PC.
1)
(A- Host PC receives the request to close from EH-ETH, and
2) replies back ACK.
(A- When the host PC does not have data to send, it replies back
3) FIN ACK.
(A- EH-ETH receives the FIN ACK and replies back ACK after
3) waiting a time designated in TIME_WAIT value.
(B). In case Host PC requests to close connection.
(B-1) Host PC requests to close connection to the EH-ETH.
EH-ETH receives the request to close from Host PC, and
(B-2)
replies back ACK
When the EH-ETH does not have data to send, it replies
(B-3)
*1
back FIN ACK.
(B-3) The host PC receives the FIN ACK and replied back ACK.
*1: This is only in case "Close mode control" is disabled. The "Close mode control" is mentioned in the
followings.
Figure 7.2.1.1 Basic procedure to open connection
Caution
- In case of the task code communication connection, a host computer must send a request to close.
Chapter 7 Automatic Sending/Receiving function (ASR)
EH-ETH
(A-1)
(A-4)
Description
Description
7-9
Host PC
(B-1)
(B-4)
(B). In case host PC requests to close connection
Segment
Sending FIN flag
Sending ACK flag
Sending FIN ACK flag
Sending ACK flag
Segment
Sending FIN flag
Sending ACK flag
Sending FIN ACK flag
Sending ACK flag
EH-ETH
(B-2)
(B-3)
EH-ETH status
Connection opened
(ESTABLISHED )
Waiting for a request
to close1
(FIN WAIT-1 )
Waiting for a request
to close1
(FIN WAIT-2 )
Waiting
(TIME WAIT ),
connection closed
(CLOSED )
EH-ETH status
Connection opened
(ESTABLISHED )
Waiting for a request
to close1
(FIN WAIT-1 )
Waiting for a request
to close1
(FIN WAIT-2 )
Waiting
(TIME WAIT ),
connection closed
(CLOSED )