Chapter 7 Automatic Sending/Receiving function (ASR)
7.2.2 Close connection
The procedure for closing connection is shown as Figure 7.9.
EH-ETH2
(A-2)
Host PC
(A) In case EH-ETH2 requests to close connection
(A-1)
(A-4)
EH-ETH2
(B-1)
Host PC
(B) In case host PC requests to close connection
(B-2)
(B-4)
(A-3)
(B-3)
(A) In case EH-ETH2 requests to close connection
Description Segment
EH-ETH2
internal status
(A-1) EH-ETH2 requests to close connection to the host PC.
Sending FIN flag
Connection opened
(ESTABLISHED )
(A-2)
Host PC receives the request to close from
EH-ETH2
, and
replies back ACK.
Sending ACK flag
Waiting for a request
to close1
(FIN WAIT-1 )
(A-3)
When the host PC does not have data to send, it replies back
FIN ACK.
Sending FIN ACK flag
Waiting for a request
to close2
(FIN WAIT-2 )
(A-4)
EH-ETH2
receives the FIN ACK and close after waiting a
time designated in Time wait value.
Sending ACK flag
Waiting
(TIME WAIT ),
connection closed
(CLOSED )
(B) In case Host PC requests to close connection.
Description Segment
EH-ETH2
internal status
(B-1) Host PC requests to close connection to the EH-ETH2.
Sending FIN flag
Connection opened
(ESTABLISHED )
(B-2)
EH-ETH2
receives the request to close from Host PC, and
replies back ACK
Sending ACK flag
Waiting for closing
(CLOSE WAIT )
(B-3)
When the EH-ETH2 does not have data to send, it replies
back FIN ACK.
(*1)
Sending FIN ACK flag
Waiting for a final
response
(LAST-ACK)
(B-4) The host PC receives the FIN ACK and replied back ACK.
Sending ACK flag
Connection closed
(CLOSED )
*1: This is only in case “Close mode control” is disabled. The “Close mode control” is mentioned in the
followings.
Figure 7.9
Basic procedure to open connection
Caution
- In case of the task code communication connection, a host computer must send a request to close.
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