[lwip-users] prioritizing of active connections

[Norbert Kleber]

Hi evereyone,

I got some questions again.

I am using the lwIP on a STM32F4 mikrocontroller without OS. A client 
will connect to the stack at two ports for transmission. First port will 
be used for controlsignals and second for datatransmission. The whole 
System works sequentially.

Firstly 1 package will be received on the ctrl connection afterwards we 
receive many packages on the dataconnection. Now I was wondering that 
the stack acknowlegded all data packages before he acknowledges the ctrl 
package. Due to the operation of the µC I can tell that he received the 
package right away and ofcause i use the acknowledgement function in the 
receive function.  But somehow it is severly delayed approx. 200ms but 
the later received data packages all get acknowledged right away.

Does the stack some prioritizing between open connections? Or is it due 
to the Ctrl Package being quite short?

Also I am doing some computational work outside of the callback 
functions and want to transmit some of the results asap over the ctrl 
connection. Is there a way to do that without waiting for the polling 
function? Or is there a way to trigger the polling function somehow for 
a instant call? Also it seemed like i can't use tcp_write if i am 
outside of a callback function (i was storing the pointer to the pcb in 
a global variable).

sincerly,

Norbert