Date: Fri, 5 Sep 2003 11:24:59 -0700 From: Luigi Rizzo <rizzo@icir.org> To: Yuchung Cheng <ycheng@cs.ucsd.edu> Cc: ipfw@freebsd.org Subject: Re: dummynet and modem pipes Message-ID: <20030905112459.A78583@xorpc.icir.org> In-Reply-To: <20030905095038.D28924@cs.ucsd.edu>; from ycheng@cs.ucsd.edu on Fri, Sep 05, 2003 at 09:50:39AM -0700 References: <20030905095038.D28924@cs.ucsd.edu>
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On Fri, Sep 05, 2003 at 09:50:39AM -0700, Yuchung Cheng wrote: > when simulating modem pipes using dummynet, how do we simulate the > modem compressions? one way is to pick a compress rate, say 2, and setup basically there is no way to accurately simulate modem compression. As a rule of thumb, for bulk traffic you can think that the main effect is the bandwidth changes (the exact ratio depends on the type of traffic), whereas for interactive apps (e.g. rpc and the like) more than compression what affects you is the additional delay that the modem causes to decide that it is time to build&send a new packet. also you'd need to take care of ip compression, not just what happens in the modem itself cheers luigi > fake larger bandwidth, but do different traffic (html, jpg, mpg) affect > the compression latency or compression rate significantly? tia > > -yuchung > _______________________________________________ > freebsd-ipfw@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-ipfw > To unsubscribe, send any mail to "freebsd-ipfw-unsubscribe@freebsd.org"
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