Re: [PATCH 2/5] TCP BIC 1.1 support

[Stephen Hemminger <shemminger@xxxxxxxx>]

On Sat, 19 Mar 2005 02:53:09 +0000
Baruch Even <baruch@xxxxxxxxx> wrote:

> Stephen Hemminger wrote:
> > This patch adds TCP BIC back in as a pluggable TCP congestion mechanism.
> > This version is closer to the TCP BIC 1.1 released for Web100.
> > The changes from 2.6.11 are:
> >     * congestion window undo fix
> >     * delayed ack compensation
> 
> This can cause overshooting if the other side doesn't do delayed acking, 
> did anyone consider the ABC (Appropriate Byte Counting) patch from 
> Yee-Ting Li? 
> http://marc.theaimsgroup.com/?l=linux-netdev&m=110917262615630&w=2
> 
> FreeBSD has an option to disable delayed acking so it's not that hard to 
> work against a host with no delayed acks at all.

I tested with FreeBSD today and see no overshoot, but I do see the undershoot
(with Reno as well), because of the extra cwnd/2 that you already observed.