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Chapter 18. TCP/IP
437
18.2.2 Programming Notes for Socket API According
to UDP
The user datagram protocol (UDP) has no flow control, so send/receive data may go missing
due to poor line conditions or difference of communications capabilities between wireless and
Ethernet. To prevent data missing, be sure to incorporate some flow control process into user
programs at both the BHT and host.
Given below are message transmission examples that support retransmission controls at each
of the BHT and host.
■
BHT’s retransmission control for a transmission error
Assume that the BHT uses the protocol of receiving transmission completion message from
the host after sending a message.
If the BHT times out for waiting a transmission completion message, it will transmit the unsent
message again.
Normal end
Transmission error in a message sent from the BHT
BHT
Disconnect
Host
Data message
Transmission
completion message
BHT
Timeout for receiving
the transmission
completion message
Disconnect
Host
Data
message
Error
Transmission
completion
message
Data message
(sent again)
Transmission
completion
message
Содержание BHT-BASIC 100 SERIES
Страница 1: ......
Страница 161: ...153 Chapter 10 Sleep Function CONTENTS 10 1 Sleep Function 154...
Страница 163: ...155 Chapter 11 Resume Function CONTENTS 11 1 Resume Function 156...
Страница 173: ...165 Chapter 13 Backlight Function CONTENTS 13 1 Backlight Function 166...
Страница 192: ...Chapter 14 Statement Reference 184 Example OPEN master Dat AS 1 FIELD 1 20 AS bar 10 AS ky CLFILE 1 CLOSE 1...
Страница 249: ...241 Example CLOSE IF kyIn Y THEN KILL Master Dat END IF Reference Statements CLFILE...
Страница 349: ...341 Run time errors Error code Meaning 05h Parameter out of the range checktype is out of the range...
Страница 383: ...375 Run time errors Reference Error code Meaning 05h Parameter out of the range Functions LEFT LEN and RIGHT...