modem: delay receiving initial ppp handshake until after sending data
(WinCE)
reduce char receive delay to 143 us
make sure picosocket buffer is empty before shutting down socket
use 536-byte segment for tcp sockets
increase linger delay to 10 sec (avoid sending RST when waiting for FIN)
picotcp: disable window scaling option
dupe ack reception in full window mode should enter dupack mode
pick the correct segment to re-xmit in recover mode
both partial frames should be enqueued when splitting segment
fix wrong size when splitting segment and crash if splitting first one
make sure re-xmit timer is correct in tcp output
579db85b3b