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Our applications sends numerous message types between a Rabbit module and a PC. A specific message always triggers a retransmission; everytime. What would cause this? There is nothing special about this message. It is a series of bytes like the other messages. How would I go about investigating? Also, a TCP Dub Ack occurs.

asked 22 Jun '15, 12:58

Impactaa's gravatar image

Impactaa
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Can you share a capture in a publicly accessible spot, e.g. CloudShark, Google Drive, Dropbox?

(22 Jun '15, 13:05) Christian_R

Can you please post the frame number in the capture file, where you believe there is something happening?

(22 Jun '15, 13:58) Kurt Knochner ♦

It is very regular. see frame 8497 and the many before that.

(22 Jun '15, 14:04) Impactaa

The retransmission timer of the 'rabbit' is very low (lower than the delay_ACK timer in windows) so when your windows application has nothing to return (in time) the rabbit device will start retransmitting the segments before windows would 'delayed' ACK the single segment received from the rabbit device. . So either the rabbit device uses a higher Retransmission Timer or your windows must reduce its delayACK timer to avoid those retransmissions .

Regards Matthias

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answered 22 Jun '15, 15:20

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mrEEde
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question asked: 22 Jun '15, 12:58

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last updated: 22 Jun '15, 15:20

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