Date: Wed, 3 Mar 2004 18:29:48 -1000 (HST) From: Vincent Poy <vince@oahu.WURLDLINK.NET> To: Charles Swiger <cswiger@mac.com> Cc: freebsd-ipfw@freebsd.org Subject: Re: ipfw/dummynet pipe size, is there a burst setting? Message-ID: <20040303182412.F8264-100000@oahu.WURLDLINK.NET> In-Reply-To: <34868EFE-6D67-11D8-85AD-003065ABFD92@mac.com>
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On Wed, 3 Mar 2004, Charles Swiger wrote: > On Mar 3, 2004, at 5:06 PM, Vincent Poy wrote: > > ipfw pipe 1 config bw size > > > > to set the size of the pipe. I noticed on Linux, they can set a burst > > size so it can burst a x number over the pipe size, is there a similar > > setting available? > > I'm not sure I understand the semantics of this? How much bandwidth is > available when using this burst mechanism-- and what traffic goes > through when several things try to burst at once, for example? I think the way the burst mechanism works is similar to ETinc's bandwidth manager in a way where it will burst up to 6KB/sec if it's available or something because I noticed their pipe size is like 490kbps for example and then they have a 420kbps setting for the lower weighted stuff and then a 6kbps burst. Maybe the burst is for the 420kbps. > Anyway, you can use different weighted queues feeding into larger-sized > pipe that will probably "do what you want"... That's what I'm doing except the issue is that with a pipe that can do 5200kbps/529kbps without shaping, as only up is the one that's important. Setting the pipe to 521kbps will give it close to 521kbps in upstream but the downstream is about 1500kbps. Then when the up pipe is set to 490kbps, the downstream is about 3000kbps. The only way to get anywhere near 5200kbps simultaneously up/down is with the up pipe at 400kbps. Is there a way to set it so that it will automatically try to use a certain larger sized pipe if there is no download traffic? > > Also, I noticed for pipes, one can set the queue size > > in slots of KBytes, how does one determine what's a good size? > > Consider the cross-product of network bandwidth times latency for your > situation; a discussion of how to tweak the TCP receive window size is > closely related... Hmm, the man pages doesn't really explain how this one works or how to calculate the size. Cheers, Vince - vince@WURLDLINK.NET - Vice President ________ __ ____ Unix Networking Operations - FreeBSD-Real Unix for Free / / / / | / |[__ ] WurldLink Corporation / / / / | / | __] ] San Francisco - Honolulu - Hong Kong / / / / / |/ / | __] ] HongKong Stars/Gravis UltraSound Mailing Lists Admin /_/_/_/_/|___/|_|[____] Almighty1@IRC - oahu.DAL.NET Hawaii's DALnet IRC Network Server Admin
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