From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Zeeff Date: Tue, 25 Nov 2003 20:05:24 +0000 Subject: [LARTC] tbf and sfq interaction??? Message-Id: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lartc@vger.kernel.org How do sfq and tbf interact when packets need to be dropped? Example: two flows are entering the linux router, flow A is 1 mbit and flow B is 3 mbits (total = 4). We use tbf to limit outgoing bandwidth to 2 mbits (further downstream there is a bottleneck). If we just used tbf, it would be dropping 50% of all packets - ie, flow A would see about 500K of it's traffic getting through and flow B would see about 1.5mbits getting through. This isn't "fair" - flow A should not have any of its packets dropped and flow B should be limited to 1 mbit. So we add sfq. What's not clear to me is if this will accomplish what I want. If the tbf algorithm occurs before sfq, tbf will drop 50% of all packets. After that, sfq will have no effect. If the sfq algorithm is performed first, then all 4 mbits of the resulting traffic is sent to tbf, then tbf will drop packets from both flows. It would seem that there needs to be some interaction between the algorithms - tbf needs to signal to sqf that more packets can be sent. But the packet dropping should occur in sqf (where fairness is understood) not in tbf. So question: will it work as I want or is a new qdisk needed? note: I actually have hundreds of flows, so I don't want to classify them manually. I also don't want hard allocations of bandwidth. If there is only flow B, 2 mbits of it should be allowed to pass. Thanks. _______________________________________________ LARTC mailing list / LARTC@mailman.ds9a.nl http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/