[lwip-devel] [bug #20511] No persist timer

[Tom Evans]

Follow-up Comment #1, bug #20511 (project lwip):

This problem can show up under the following circumstances:

If lwIP has send enough data that the "remote" has filled its received window
and has returned a zero (or smaller than the segment lwIP wants to send)
window, lwIP stops. When the window opens, the remote sends an ACK with a
window update. If this packet gets lost (this is a common occurrence), then
lwIP won't send data until the other end sends another window update. It will
only do this if it has some data to send back. So in a unidirectional data
transfer setup, one missed window update/ACK packet results in lwIP locking
up.

The reference for this is in the section "Managing the Window" on
page 42 of RFC793:

    ftp://ftp.rfc-editor.org/in-notes/rfc793.txt

And in section 4.2.2.17 of:

    ftp://ftp.rfc-editor.org/in-notes/rfc1122.txt

For previous discussion on this issue, and why it might be a bit tricky,
please refer to the following posts in the lwip-users list:

http://lists.nongnu.org/archive/html/lwip-users/2007-06/msg00033.html
http://lists.nongnu.org/archive/html/lwip-users/2007-06/msg00034.html
http://lists.nongnu.org/archive/html/lwip-users/2007-06/msg00037.html
http://lists.nongnu.org/archive/html/lwip-users/2007-06/msg00042.html
http://lists.nongnu.org/archive/html/lwip-users/2007-06/msg00043.html
http://lists.nongnu.org/archive/html/lwip-users/2007-06/msg00032.html
http://lists.nongnu.org/archive/html/lwip-users/2007-06/msg00077.html


    _______________________________________________________

Reply to this item at:

  <http://savannah.nongnu.org/bugs/?20511>

_______________________________________________
  Message sent via/by Savannah
  http://savannah.nongnu.org/