I don't know
why Atte's approach or other method which sends ack directly as
TF_ACK_DELAY flag is set
will increase
duplicate acks. Since TF_ACK_DELY is set means there must be some acks pending
and
tcp_output
will always clear flags of TF_ACK_DELY &TF_ACK_NOW after sending out
an ack, duplicate acks
would be sent
only as TF_ACK_DELY &TF_ACK_NOW is not set. Of coures,there
may be some other reason
I
missed will increase duplicate acks.
Regards,
Bo-Er