[pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3)

kristopher.doyen at gmail.com kristopher.doyen at gmail.com
Tue Jun 28 08:07:48 CDT 2011


Since UDP works I have my doubts it is a driver/interface link issue. 

This sounds more like a latency/packet loss issue (esp since it is a transatlantic link). 

What type of latency, packet loss, and or packet error rates are you seeing?


-----Original Message-----
From: Eugen Leitl <eugen at leitl.org>
Date: Tue, 28 Jun 2011 10:52:55 
To: NANOG list<nanog at nanog.org>
Subject: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3)

----- Forwarded message from William Salt <williamejsalt at googlemail.com> -----

From: William Salt <williamejsalt at googlemail.com>
Date: Tue, 28 Jun 2011 08:03:25 +0100
To: support at pfsense.com
Subject: [pfSense Support] Strange TCP connection behavior 2.0 RC2 (+3)
Reply-To: support at pfsense.com

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.

At either end, we have a media converter, and a supermicro server with an
intel quad port NIC running pfsense 2 (RC2 at one end RC3 at the other) and
the IGB driver on the quad port.

We can pass 1gbps either way with UDP. However we are experiencing very
strange issues with tcp connections.

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.

Each TCP connection starts very slowly, and will max out at around 190mbps,
taking nearly 2 minutes to climb to this speed before *plateauing*.

We have to initiate many (5+) connections to saturate the link with tcp
connections with iperf.

Real world tests transferring files, max out at 100mbps, using multiple
connections.

I have followed guides like this:
http://www.psc.edu/networking/projects/tcptune/#FreeBSD

With no luck, and have tweaked, disabled, and enabled nearly every relevant
sysctl parameter with no luck.

Can anyone shed some light on this?

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 - pfsense (or 8.2 for our production
systems).
I have tried the freebsd net mailinglist, but im hoping you lot can help me!

Cheers in advance
Will

----- End forwarded message -----
-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
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