[lwip-users] TCP Zero Window

[norbert . kleber]

Hi all,

I have a small question. Under which circumstances does the lwIP stack 
reduce the window size even while the window update is disabled.

I am sending 16 kB to the microcontroller (lwIP-Stack) copy them to a 
certain address and send them back to the laptop (linux). At the end of 
the 66th receive cycle i receive an unexpected package and with the
acknowledgement the lwIP stack reduces the window size by the length of 
the last 2 received packages. Afterwards we receive another unexpected 
package that is equal to the length of the window. From this point on 
the stack sends all 16 kB back and advertises the window size 0. The 
stack doesn't recover from that and will only send  zero windows 
afterwards. A change of the amount of buffers and the size of them had 
no influence on this problem.

greetings,

Norbert