Re: [lwip-users] Re-Transmission from PC is ignored due to sequence number

[address@hidden]

On 23.04.2018 17:08, Sergio R. Caprile wrote:
> Take a look at frame #22, my Wireshark says "previous segment info not
> captured" and its SEQ is 216.
> Previous device frame in capture is #19 with SEQ 178 and len 21, which
> is consistent with the PC ACKing 199 in frames #20/21.
> There is a missing frame with SEQ 199 and len 17 that was supposedly
> sent by lwIP.
> Consistent with a Modbus response for 4 registers, as you ask on #20/21
>
> Did you wait long enough ? Your capture file ends right there. Perhaps
> lwIP timer is longer ?

lwIP should retransmit the lost packet after a time between some 100ms 
and some sconds. The capture is clearly not long enough. However, If the 
packet that gets retransmitted got lost before, it could be a bug that 
makes it get lost again...

> Otherwise... We' found a bug in lwIP or in your driver/hardware.

I'll vote for the driver. At least if it's a hardware vendor driver ;-)

Simon