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

[Sylvain Rochet]

Hi Marco,


On Fri, Nov 25, 2016 at 01:22:13PM +0100, Simon Goldschmidt wrote:
> 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

Added to that, try disabling VJ compression (VJ_SUPPORT = 0), VJ support 
in 1.4.1 is not working properly.


> 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.

Yup. At least I'm not going for a deep analysis of the issue because I'm 
confident, if the issue exists, that it is fixed in 2.0.0.


Sylvain

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