Hi Norbert!
The advertised receive window size specifies the amount of memory the
stack can consume without further acknowledgement. Once the
application
side has read received data and acknowledged/freed it, the receive
window is enlarged by this amount and - after a certain timeout - a
window update packet is send to the server to inform about the
enlarged
receive window. If your application is reading the data very slowly,
the
windows size will go down to zero and open up on read.
Modifying the receive window size can be used to optimize the
throughput. A larger receive window allows more data to be on the fly
(not acknowledge by the client) but requires more work to recover from
lost data, especially if out of order queueing is disabled.
If your receive windows does not open up again, you likely did not
read
all data received.
Jan
On 09.09.2016 10:18, address@hidden wrote:
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
_______________________________________________
lwip-users mailing list
address@hidden
https://lists.nongnu.org/mailman/listinfo/lwip-users
_______________________________________________
lwip-users mailing list
address@hidden
https://lists.nongnu.org/mailman/listinfo/lwip-users