Re: [lwip-users] [Issue] TCP fragmentation over PPP - fragments are lost in LwIP if data is queued for sending

[Simon Goldschmidt]

Marco Jakobs wrote:
>  [..]
> Writing a known pattern in the payload I confirm that the first two packets 
> of 1024 bytes
> are matching! So the 3rd fragment of 752 is just not sent over the PPP.
> 
> Using the PPP_DEBUG I can see that pppifOutput is just called 2 times with a 
> LEN of 1024
> bytes each. For the last 752 bytes fragment, pppifOutput is not called.

- Try disabling TCP nagle to see if that's a problem
- debug the pcb to see how many segments are in unsent/unacked of the pcb 
sending to PPP

One problem is that we don't really have support for 1.4.1 PPP, as Sylvain 
really rewrote PPP
for 2.0.0 and wasn't there before to know the "old" PPP.

Keeping that aside, to me this still looks like some kind of race condition 
induced by threading issues...


Simon