Date: Thu, 22 Nov 2012 13:38:36 +0100 From: Marc Peters <marc@mpeters.org> To: Ingo Flaschberger <if@xip.at> Cc: freebsd-net@freebsd.org Subject: Re: Low Bandwidth on intercontinental connections Message-ID: <50AE1CCC.7080706@mpeters.org> In-Reply-To: <50AE0B12.8000309@xip.at> References: <50ACF62C.8000408@mpeters.org> <CAOgwaMuUuJ2%2BmKqsFVp=DyVFkfm8Et%2Brnt2iEGDO8i1Kt_kDVA@mail.gmail.com> <50ad087d.1892cc0a.2cce.3bf2@mx.google.com> <50AD1012.7020209@mpeters.org> <50AD14F8.8050001@xip.at> <50ADE5E4.9090708@mpeters.org> <50AE0B12.8000309@xip.at>
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On 11/22/2012 12:22 PM, Ingo Flaschberger wrote: > >>> *) check and compare tcpdump >> for the FreeBSD hosts on the receiver side, it showed a lot of window >> size changes and from time to time a lot of duplicate ACKs. i will file >> a PR (as Adrian asked) and see to get a matching tcpdump and SIFTR >> output. > > *) can you check which ping-sizes work? > ping -s 1472 > ping -D -s 1472 (should work if you have a mtu of 1500 all over the > way) interesting, the MTU is way lower, than i expected. Through the VPN tunnel, only 1322 bytes are possible without fragmentation. ScreenOS adds 42 additional bytes per paket and the FreeBSD box is receiving 1364 bytes, according to tcpdump. From the outside (only one Netscreen on the way), 1472 is the maximum possible size to send pakets without fragmentation (-D). Which MTU would you suggest to use? Shouldn't the MTU discovery of FreeBSD handle this correct? > > *) any offloading/supported used at the network-card? Yes: bce0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500 options=c01bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,VLAN_HWTSO,LINKSTATE> ether ac:16:2d:b7:00:f4 inet 172.16.3.10 netmask 0xffffff00 broadcast 172.16.3.255 inet6 fe80::ae16:2dff:feb7:f4%bce0 prefixlen 64 scopeid 0x1 nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL> media: Ethernet autoselect (1000baseT <full-duplex>) status: active > *) try a rate-shaping queue outgoing (not really good - as shaping works > best on incomming interfaces): > you need dummynet (and ipfw for this example): > ipfw add pipe 1 all from .... > ipfw pipe 1 config bw 10Mbit/s queue 50Kbytes > (adjust queue size ~40ms at rated speed) no paketfiltering on the host itself is intended and i don't know anything of ipfw for a simple setup, sorry. marc > > Kind regards, > Ingo Flaschberger > > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"
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