XMODEM ACK/NACK used out of sequence
Eröffnet am: 2019-03-05 20:30
Letztes Update: 2019-03-05 20:30
| Auswertung: | (Anonym) | Verantwortlicher: | (Keine) |
|---|---|---|---|
| Priorität: | 5 - Mittel | Meilenstein: | (Keine) |
| Typ: | Fehler | Schweregrad: | 5 - Mittel |
| Komponente: | (Keine) | Status: | Offen |
| Lösung | Keine |
Einzelheiten
I use teraterm xmodem to send a file to my application X. Please note teh timing are NOT the remmended timing for xmodem, but they are no real specification, just suggestion for the author. When X receive a full block (lets say block 1), send back an ACK and wait ~15ms to see new data; but seems xmodem is taking up to 30ms. That is not a big problem, my program send a NACK after 15ms, then wait again; I expect to receive again block 1 if the fisrt ACK was lost, or block 2 if ACK was received. teraterm send block 2. Not a problem, i receive it and send an ACK. BUT now teraterm does NOT use the last receive byte (ACK) but instead uses the "old" NACK; it will resend block 2! that does not look as a big problem until you realize that ACK i sent will be seen as ACK for block 3, something we didn't even initialize.
A possible solution would be to use last received byte
Letzte Aktualisierung für dieses Ticket
2019-03-05 20:30 Aktualisiert von: None
- New Ticket "XMODEM ACK/NACK used out of sequence" created