Subject: Re: Up-stream bandwidth shaping without resorting to linux/iptables?
To: NetBSD User's Discussion List <netbsd-users@NetBSD.org>
From: Steven M. Bellovin <firstname.lastname@example.org>
Date: 02/05/2005 17:53:59
In message <m1CxYca-0024g3C@building.weird.com>, "Greg A. Woods" writes:
>Well with any bandwidth management tool in any IP network it is only
>possible to control what one sends, but not what one receives.
>(You could control what you receive, but there's no point since it has
>to cross the narrower wire to get to your control point anyway.)
Actually, at least for TCP and well-behaved UDP applications, that's
not so. Dropped packets are interpreted by the sender as an indication
of congestion, which will cause it to slow down. Another strategy (I
suspect, though I haven't tried it) is to delay ACKs, since the sending
TCP will use the ACk arrival rate to clock the sending rate.
--Prof. Steven M. Bellovin, http://www.cs.columbia.edu/~smb