Subject: TCP limited transmit To: None <> From: Mark Allman <>
List: tech-net Date: 11/28/2000 13:36:34  A slight change to
TCP's algorithms (called Limited Transmit) is in the RFC
Editor's queue and will be published as a proposed standard
soon.  The proposal basically calls for new data (if available)
to be transmitted when the first and second duplicate ACKs
arrive. Additional constraints are that cwnd is not supposed to
be changed and we need to ensure that we don't oversubscribe
cwnd by more than  I have hacked together some changes for
netbsd to implement this change.  I'm not sure what I have is
the Right Way to do things, but it seems reasonable to me and it
seems to work fine.  I thought I'd submit these changes for
possible inclusion in the standard version of netbsd.  Then, in
tcp_input.c:                                  } else if
(tp->t_dupacks > tcprexmtthresh) {
tp->snd_cwnd += tp->t_segsz;
(void) tcp_output(tp);
goto drop; #ifdef MALLMAN                                 /*
limited transmit algorithm */                                 }
else if (do_lim_xmit &&