Date: Mon, 19 Aug 2002 15:41:42 -0700 From: Luigi Rizzo <rizzo@icir.org> To: Carlos Carnero <zopewiz@yahoo.com> Cc: freebsd-net@FreeBSD.ORG Subject: Re: Bandwidth throttling with dummynet(4) Message-ID: <20020819154141.A41050@iguana.icir.org> In-Reply-To: <20020819203323.25886.qmail@web21411.mail.yahoo.com>; from zopewiz@yahoo.com on Mon, Aug 19, 2002 at 01:33:23PM -0700 References: <20020819203323.25886.qmail@web21411.mail.yahoo.com>
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dummynet pipes use timers heavily, and i suspect that the timer granularity in vmware might not be as good as you would want, resulting in a throughput which is a fraction of what you have configured in the pipes. Also, 5Kbytes/s is a very low bandwidth, which coupled with 50 queue slots (~75Kbytes with large packets) will result in very large RTTs which could in turn trigger useless retransmissions and timeouts. I would first check if timing is accurate by setting a delay-only pipe and seeing if ping times correspond to what you have configured. Secondly, i would reduce the queue size to something reasonable e.g. 10Kbytes to avoid the potentially huge RTTs. cheers luigi On Mon, Aug 19, 2002 at 01:33:23PM -0700, Carlos Carnero wrote: > Hi, > > I have a "lab" here where I'm testing (and learning) > traffic shaping with dummynet(4). I have a Windows XP > host computer and a couple of VMware virtual > computers: one running FreeBSD 4.5-RELEASE-p18, with > two virtual Ethernet adapters and other running NetBSD > 1.5.2 with one adapter. My FreeBSD "box" is the > router/gateway for the NetBSD box, providing > firewalling and NAT. Pretty much a standard setup, and > it works OK (you should see the double NATting ;) > > Anyway, I have compiled into the kernel both IP Filter > and FreeBSD's own ipfw, with the purpose of traffic > shaping/bandwidth throttling. But the numbers I get > are not what I expect. For instance, my ipfw rules are > like: > > pipe 1000 config bw 5KByte/s queue 50 > pipe 1001 config bw 5KByte/s queue 50 > > add 50000 pipe 1000 tcp from 192.168.250.3/32 to any > add 50001 pipe 1001 tcp from any to 192.168.250.3/32 > > (192.168.250.3 being the NetBSD "box") But when I > transfer a file using FTP from the Windows host I get > _almost_ 1 KByte. Note that I remove the pipes speeds > reach ~800-900 KByte/s, almost saturating the > "virtual" Ethernet interfaces. Changing the pipe > bandwidth to, say 25KByte/s in both pipes yield an FTP > speed of ~5-6 KByte/s. Is this OK or FTP is that > inefficient? What other tests can I run to check the > bandwidth _not_ using FTP? > > IP Filter's ruleset is currently set to pass > everything as quickly as it can :) > > Thanks a lot, > Carlos. > > PS. Posting from Yahoo! until I solve some reverse DNS > bugs I inherited :| > > __________________________________________________ > Do You Yahoo!? > HotJobs - Search Thousands of New Jobs > http://www.hotjobs.com > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-net" in the body of the message To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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