Anyone?
2013/8/23 Rodrigo Garbi <[email protected]> > Hi! > I'm working with FreeRTOS v7.0.1 and LwIP 1.4.0 and I'm facing the > following problem: > > Device A and B transmit data every 40 ms to my board (where I'm running > LwIP) and once in a while I can notice some data from device A is being > missed. > > So I did some research with CommView and found that: > > 1) Device A sends data (9 bytes length) to my board and get correct ACK > from it: > Sequence: 0x13D5388C (332740748) > > Acknowledgement: 0x00001A57 (6743) > > Response from my board: > Sequence: 0x00001A57 (6743) Acknowledgement: 0x13D53895 (332740757) > > 2) Device A send 9-bytes data to my board, but this won´t ACK: > Sequence: 0x13D5389E (332740766) Acknowledgement: 0x00001A57 (6743) > Sequence: 0x00001A57 (6743) Acknowledgement: 0x13D5389E (332740766) > 3)Device A does not care about it (maybe because data is already in > ethernet transceiver buffer) and sends a new data (9-bytes); my board will > not ACK it: > Sequence: 0x13D538A7 (332740775) Acknowledgement: 0x00001A57 (6743) > Sequence: 0x00001A57 (6743) Acknowledgement: 0x13D5389E (332740766) > > 4)Same as 3 > Sequence: 0x13D538B0 (332740784) Acknowledgement: 0x00001A57 (6743) > Sequence: 0x00001A57 (6743) Acknowledgement: 0x13D5389E (332740766) > > 5) Same as 3 > > Sequence: 0x13D538B9 (332740793) Acknowledgement: 0x00001A57 (6743) > Sequence: 0x00001A57 (6743) Acknowledgement: 0x13D5389E (332740766) > 6) Finally, device A is aware of the problem and retransmits data, but > instead of transmitting 36 bytes (9 x 4), only transmits 18 bytes > Sequence: 0x13D5389E (332740766) Acknowledgement: 0x00001A57 (6743) Data > length: 0x12 (18) > > > And my board running Lwip 1.4.0 will acknowledge 36 bytes instead of 18: > Sequence: 0x00001A57 (6743) Acknowledgement: 0x13D538C2 (332740802) > > > So device A won´t transmit last two 9-bytes packets, and they will be lost! > > Anyone can help me with this? Is it a bug in LwIP or what is happening? > Thank you! > >
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