Date: Tue, 28 Jun 2011 19:06:10 +0100 From: "Scheffenegger, Richard" <rs@netapp.com> To: "William Salt" <williamejsalt@googlemail.com> Cc: freebsd-net@freebsd.org Subject: RE: 1gbit LFN WAN link - odd tcp behavior Message-ID: <5FDC413D5FA246468C200652D63E627A0F014ED7@LDCMVEXC1-PRD.hq.netapp.com> In-Reply-To: <BANLkTi=s0fNVajYrO2JSkvyVLheqp3QDHw@mail.gmail.com> References: <BANLkTi=s0fNVajYrO2JSkvyVLheqp3QDHw@mail.gmail.com>
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What is the effective latency under load, and the packet loss probability? Just to add some more detail. Richard Scheffenegger > -----Original Message----- > From: William Salt [mailto:williamejsalt@googlemail.com] > Sent: Montag, 27. Juni 2011 12:15 > To: freebsd-net@freebsd.org > Subject: 1gbit LFN WAN link - odd tcp behavior >=20 > Hi All, > For the last couple of months i have been pulling my hair out > trying to solve this problem. > We have a 1Gbps transatlantic link from the UK to the US, which has > successfully passed the RFC2544 test. >=20 > At either end, we have a media converter, and a supermicro server with > an > intel quad port NIC running pfsense 2 (freebsd 8.1) with the NIC > running on > the yandex IGB driver. >=20 > We can pass 1gbps either way with UDP. However we are experiencing very > strange issues with tcp connections. >=20 > With window scaling enabled, and a max socket buffer set to 16MB, we > see no > difference. > Even disabling window scaling and setting the window to 16MB makes no > difference. >=20 > Each TCP connection starts very slowly, and will max out at around > 190mbps, > taking nearly 2 minutes to climb to this speed before *plateauing*. >=20 > We have to initiate many (5+) connections to saturate the link with tcp > connections with iperf. >=20 > I have followed guides like this: > http://www.psc.edu/networking/projects/tcptune/#FreeBSD >=20 > With no luck, and have tweaked, disabled, and enabled nearly every > relevant > sysctl parameter with no luck. >=20 > Can anyone shed some light on this? >=20 > I am now doubting the IGB driver, and am looking to swap out the cards > as a > last ditch effort. > However, we have tried different hardware (L3 switches, media convertes > + > laptops etc), and the symptoms still persist... > The only constant is freebsd 8.1 (or 8.2 for production systems). >=20 >=20 > Cheers in advance > Will > _______________________________________________ > 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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