Appendices
■Phase 2 with NAK
If the sending station receives a NAK from the receiving station in response to a transmission block containing text data m, it sends that transmission block again immediately as shown below.
If the sending station receives an ACK before receiving a NAK 10 times in succes- sion, it continues the subsequent message transmission.
Sending station
Data text m
NAK
Data text m
Receiving station
NAK
Data text m
ACK
Data text m+1
If the sending station receives a NAK 10 times in succession or it fails to send a same transmission block, it shifts to phase 3 to terminate the message transmis- sion abnormally. Even if phase 3 terminates normally, the transmission results in an abnormal end.
Sending |
|
| |
station | Data text m (1) | ||
|
|
| NAK |
|
| Data text m (2) | |
|
|
| NAK |
|
| Data text m (10) | |
|
|
| NAK |
|
|
|
|
| Occurrence |
| |
| of an error |
| |
|
|
|
|
Receiving station
To phase 3.
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