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Re: [lwip-users] Re-Transmission from PC is ignored due to sequence numb
Re: [lwip-users] Re-Transmission from PC is ignored due to sequence number
Mon, 23 Apr 2018 17:49:54 +0200
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On 23.04.2018 17:18, Patrick Klos wrote:
Thinking about the retransmission from PC side:
Shouldn't lwip also do a retransmission of the lost frame?
You know, these bytes never get acknowledged by PC.
Yes, the LwIP side should have retransmitted the packet. Packet 21 of
the trace file shows an ACK of 00009b45, so even though the LwIP device
thought it sent a response to the PC (bumping the ACK to 00009b56), LwIP
should have noticed that and resent the data from the previous packet.
On what basis do you say that? Retransmissions are triggered mainly in
a) timeout (this did not happen here)
b) dup-acks: a fast retansmission is done if 2 duplicate acks are
receiver (i.e. three times the same ACK). This is not the case here, we
just received the 2nd ACK.
I'm still saying lwIP is correct.