On 11/7/07, Martin Toft <[EMAIL PROTECTED]> wrote: > > Hi, > > I'm experiencing some mysterious transfer speed differences. I have a > virtual Linux-server at HostEurope, Germany, and it appears that > machines running OpenBSD can only download from the Linux-server with > approx 300 kB/s, whereas machines running Linux can download with approx > 1.5 MB/s from the server. > > I have conducted a small test to clarify what I'm talking about. The > involved machines: > > - sauerkraut.obsd.dk (87.230.22.203) (Debian GNU/Linux, 2.6.9 kernel). > - gw.obelnet.dk (130.225.243.84) (OpenBSD 4.2-stable). > - matrix.math.aau.dk (130.225.48.12) (Ubuntu Linux, 2.6.20 kernel). > > sauerkraut.obsd.dk is the server at HostEurope, and it offers a 50 MB > download > at http://obsd.dk/50MB, which I'll download from the other two machines. > > gw.obelnet.dk: > > [EMAIL PROTECTED]:~$ wget -O /dev/null http://obsd.dk/50MB > --21:03:22-- http://obsd.dk/50MB > => `/dev/null' > Resolving obsd.dk... 87.230.22.203 > Connecting to obsd.dk|87.230.22.203|:80... connected. > HTTP request sent, awaiting response... 200 OK > Length: 52,428,800 (50M) [text/plain] > > 100%[====================================>] 52,428,800 334.12K/s ETA > 00:00 > > 21:05:57 (331.55 KB/s) - `/dev/null' saved [52428800/52428800] > > matrix.math.aau.dk: > > [EMAIL PROTECTED]:~$ wget -O /dev/null http://obsd.dk/50MB > --21:06:45-- http://obsd.dk/50MB > => `/dev/null' > Resolving obsd.dk... 87.230.22.203 > Connecting to obsd.dk|87.230.22.203|:80... connected. > HTTP request sent, awaiting response... 200 OK > Length: 52.428.800 (50M) [text/plain] > > 100%[====================================>] 52.428.800 1.59M/s ETA > 00:00 > > 21:07:17 (1.56 MB/s) - `/dev/null' saved [52428800/52428800] > > I have attached three traceroutes -- from gw.obelnet.dk to > sauerkraut.obsd.dk, > from matrix.math.aau.dk to sauerkraut.obsd.dk, and from gw.obelnet.dk to > matrix.math.aau.dk. The last one illustrates how close gw.obelnet.dk and > matrix.math.aau.dk are located, network wise. Both are connected through > Aalborg University, which is connected through the Danish Network for > Research > and Education, which again is connected through NORDUnet (a collaboration > between nordic research networks). > > What baffles me most is that when I make a ssh tunnel from gw.obelnet.dk > through matrix.math.aau.dk to sauerkraut.obsd.dk, I can download the 50 > MB file with approx 1.5 MB/s: > > [EMAIL PROTECTED]:~$ grep obsd.dk /etc/hosts > 127.0.0.1 localhost.obelnet.dk localhost obsd.dk > [EMAIL PROTECTED]:~$ ssh -N -L 4000:obsd.dk:80 matrix.math.aau.dk & > [EMAIL PROTECTED]:~$ wget -O /dev/null http://obsd.dk:4000/50MB > --21:26:23-- http://obsd.dk:4000/50MB > => `/dev/null' > Resolving obsd.dk... 127.0.0.1 > Connecting to obsd.dk|127.0.0.1|:4000... connected. > HTTP request sent, awaiting response... 200 OK > Length: 52,428,800 (50M) [text/plain] > > 100%[====================================>] 52,428,800 1.47M/s ETA > 00:00 > > 21:26:55 (1.54 MB/s) - `/dev/null' saved [52428800/52428800] > > Beside the test above, I have also downloaded the 50 MB file from a > Linux box (Debian GNU/Linux, 2.6.x kernel) and an OpenBSD box > (4.2-current), both directly behind gw.obelnet.dk. gw.obelnet.dk is > a NAT gateway for the two boxes, as you might have guessed. The numbers > from above are confirmed -- the Linux box downloads with 1-1.5 MB/s, and > the OpenBSD box downloads with 270-300 kB/s. > > Can anybody explain these differences? Why are the downloads so slow on > OpenBSD? > > Any help is appreciated. If you think I've left something important out, > don't hesitate to ask. > > Best regards, > Martin > > > Attachments: > > Traceroute from gw.obelnet.dk to sauerkraut.obsd.dk: > > [EMAIL PROTECTED]:~$ traceroute -P 1 sauerkraut.obsd.dk > traceroute to sauerkraut.obsd.dk (87.230.22.203), 64 hops max, 60 byte > packets > 1 gi1-0-1.aalborg1.aau.dk (130.225.243.65) 0.769 ms 0.814 ms > 0.802 ms > 2 icdata.ly4.core.fsknet.dk (130.225.242.34) 6.758 ms 6.392 ms > 6.606 ms > 3 teng-ly4.ly3.core.fsknet.dk (130.225.244.145) 6.275 ms 6.634ms > 6.683 ms > 4 10g-ly3.or1.core.fsknet.dk (130.225.244.218) 6.615 ms 7.184 ms > 6.924 ms > 5 dk-ore.nordu.net (193.10.68.121) 6.791 ms 6.726 ms 6.608 ms > 6 se-fre.nordu.net (193.10.68.117) 16.359 ms 16.418 ms 16.604 ms > 7 s-b3-link.telia.net (213.248.97.17) 20.683 ms 20.695 ms 17.285ms > 8 s-bb1-link.telia.net (80.91.254.58) 20.385 ms 20.360 ms 16.842ms > 9 ffm-bb1-link.telia.net (80.91.251.145) 43.569 ms 44.25 ms > 47.294 ms > 10 ffm-b1-link.telia.net (80.91.254.97) 47.347 ms 47.275 ms 47.236ms > 11 pipex-115772-ffm-b1.c.telia.net (213.248.102.158) 51.53 ms > 54.802 ms 50.290 ms > 12 xe-6-1-0.juwel.cgn3.hosteurope.de (80.237.129.114) 49.954 ms > 49.954 ms 50.155 ms > 13 xe-16-1.mlx31m.cgn3.hosteurope.de (80.237.129.118) 44.355 ms > 43.938 ms 47.882 ms > 14 * * * > 15 sauerkraut.obsd.dk (87.230.22.203) 44.167 ms 43.965 ms 47.766ms > > Traceroute from matrix.math.aau.dk to sauerkraut.obsd.dk: > > [EMAIL PROTECTED]:~$ traceroute -I sauerkraut.obsd.dk > traceroute to sauerkraut.obsd.dk (87.230.22.203), 30 hops max, 40 byte > packets > 1 ciscoa (130.225.48.254) 1.044 ms 1.006 ms 1.015 ms > 2 gi-gw4.aalborg2.aau.dk (192.38.59.2) 0.430 ms 0.402 ms 0.401 ms > 3 icdata.ly4.core.fsknet.dk (130.225.242.34) 6.045 ms 6.054 ms > 6.034 ms > 4 teng-ly4.ly3.core.fsknet.dk (130.225.244.145) 5.978 ms 5.972ms > 5.959 ms > 5 10g-ly3.or1.core.fsknet.dk (130.225.244.218) 6.483 ms 6.506 ms > 6.471 ms > 6 dk-ore.nordu.net (193.10.68.121) 6.421 ms 6.432 ms 6.403 ms > 7 se-fre.nordu.net (193.10.68.117) 16.172 ms 16.182 ms 16.147 ms > 8 s-b3-link.telia.net (213.248.97.17) 32.140 ms 20.068 ms 16.418ms > 9 s-bb1-link.telia.net (80.91.254.58) 20.093 ms 16.391 ms 20.038ms > 10 ffm-bb1-link.telia.net (80.91.251.145) 47.058 ms 47.037 ms > 47.074 ms > 11 ffm-b1-link.telia.net (80.91.254.97) 47.108 ms 47.017 ms 43.327ms > 12 pipex-115772-ffm-b1.c.telia.net (213.248.102.158) 49.744 ms > 49.727 ms 46.568 ms > 13 xe-6-1-0.juwel.cgn3.hosteurope.de (80.237.129.114) 59.206 ms > 55.756 ms 46.009 ms > 14 xe-16-1.mlx31m.cgn3.hosteurope.de (80.237.129.118) 43.659 ms > 43.619 ms 47.294 ms > 15 * * * > 16 sauerkraut.obsd.dk (87.230.22.203) 47.355 ms 47.274 ms 43.667ms > > Traceroute from gw.obelnet.dk to matrix.math.aau.dk: > > [EMAIL PROTECTED]:~$ traceroute -P 1 matrix.math.aau.dk > traceroute to matrix.math.aau.dk (130.225.48.12), 64 hops max, 60 byte > packets > 1 gi1-0-1.aalborg1.aau.dk (130.225.243.65) 0.573 ms 0.658 ms > 0.821 ms > 2 gi1-1.aau-gw1.aau.dk (192.38.59.65) 0.558 ms 0.567 ms 0.527 ms > 3 aau-gw4.auc.dk (130.225.52.11) 1.243 ms 1.717 ms 1.72 ms > 4 matrix.math.aau.dk (130.225.48.12) 0.575 ms 0.690 ms 0.762 ms > > What is the tcp windowsize of your machine ? OpenBSD in default install runs with window size of 16k, which in the aprox 40ms RTT seen in the trace about gives a theoretical max of ~400kByte/sec.
If you increase that to the 64k your linux boxes probably run that would give ~ 1600kByte/sec. /Tony
