Date: Thu, 11 Oct 2007 23:34:53 +0900 From: Byung-Hee HWANG <bh@izb.knu.ac.kr> To: Lawrence Stewart <lstewart@room52.net> Cc: James Healy <jhealy@swin.edu.au>, freebsd-net@freebsd.org Subject: Re: Software for FreeBSD TCP R&D: SIFTR v1.1.4 and DPD v1.0 released Message-ID: <1192113293.8383.15.camel@viola.izb.knu.ac.kr> In-Reply-To: <470D88E2.5070707@room52.net> References: <470C2DFD.20109@room52.net> <1192006616.6441.16.camel@viola.izb.knu.ac.kr> <470D88E2.5070707@room52.net>
next in thread | previous in thread | raw e-mail | index | archive | help
On Thu, 2007-10-11 at 12:22 +1000, Lawrence Stewart wrote: > Hi Byung-Hee, > > Byung-Hee HWANG wrote: > > On Wed, 2007-10-10 at 11:42 +1000, Lawrence Stewart wrote: > > > >> Hi All, > >> > >> Just a quick heads up regarding the availability of a new SIFTR > >> (Statistical Information for TCP Research) version and the debut release > >> of DPD (Deterministic Packet Discard). > >> > >> SIFTR v1.1.4 addresses a couple of issues, one of which is applicable to > >> users of SIFTR in FreeBSD 7-CURRENT. Read the changelog and readme for > >> more information. > >> > >> DPD is a new FreeBSD kernel module we developed to further aid us in our > >> ongoing TCP research. It allows for the deterministic dropping of TCP > >> packets from within the FreeBSD kernel via a simple sysctl interface. > >> This is particularly useful for anyone that is interested in observing > >> TCP reacting to packet loss events (e.g. congestion control > >> researchers). Being able to drop the same packet(s) across multiple > >> tests allows for simpler comparisons of TCP behaviour. We've found it > >> particularly useful in evaluating and observing the behaviour of > >> different congestion control mechanisms, and hope it may be of use to > >> others out there. Please refer to the DPD readme for more in-depth > >> information. > >> > >> The software and documentation is freely available under a BSD licence from: > >> > >> http://caia.swin.edu.au/urp/newtcp/tools.html > >> > >> We would be very happy to hear from anyone regarding bugs and > >> suggestions as well. > >> > > > > First of all, I would like to thank you for your good efforts. Its > > almost feature seems like PF(4), however, it's useful to me, maybe. > > > > Thanks! > > w.r.t. PF, as far as I'm aware, it does not allow the user to drop > arbitrary packets identified by number within a TCP flow. Dummynet with > its uniform packet loss pipe configuration is about the closest thing to > DPD that I know of. The problem with Dummynet's uniform packet loss is > that you have no control over which packets get dropped, which makes > analysing TCP behaviour very difficult indeed. That said, I could simply > be blissfully unaware that such functionality exists in PF. > > > Are you willing to support IPv6 for both SIFTR and DPD? > > > In the short term, our research does not entail the use of IPv6 and > there is currently insufficient time available for implementing > functionality that is not immediately useful to us. > > That said, it should be fairly straight-forward work to add IPv6 > support, and I'd be more than happy to give you all the pointers and > tips required to carry out the modifications if you were so inclined. I don't want that my comment can force your thinking for implementing. IPv6 support, it was just my wish list for your software. So never mind. And if I encounter strange problems, then I'll give you email;; Thanks, -- Byung-Hee HWANG <bh@izb.knu.ac.kr> "Michael, it's not true, please say it's not true." -- Kay Adams, "Chapter 31", page 434
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?1192113293.8383.15.camel>