[netperf-talk] Generating network traffic on a dual port NIC with a single computer using netperf???

[Werner Hoehenrieder]

Jesse / Rick,

Many many thanks for the quick response.

I "feel better" knowing that it wasn't just something simple that I overlooked - and I appreciate the details you provided.

For normal lab use - getting two systems is simple enough - but I was looking into making a more "portable" traffic solution - therefore the single computer requirement.

After googling the "send to self" term - I find that this may still be possible - as several have certainly done this.

On a side note:  I was/am playing around with Ostinato - a GPL traffic generator which shows promise (although still fairly early on in development).  It does work in a single system (ie. send to self) configuration (on Linux) without any special patches (that I know of - since I didn't install any).  My main issue with Ostinato was that thruput wasn't as high as I'd like (probably more overhead) and it doesn't have any provision for automation/scripting (yet - that's a future feature).

Conversely - netperf is simple to add to scripts - and can generate higher traffic rates.  I think it's a better solution at this time if I want to create something "simple" to just provide a technician to run.

BTW:  The Brocade 1020 CNA is a Gen2 x8 PCIe adapter - so it has the bandwidth needed to run line rate.

Thanks again to both of your on your quick replys/support.

Regards,
 Werner
________________________________________
From: Jesse Brandeburg [jesse.brandeburg at intel.com]
Sent: Thursday, December 09, 2010 5:16 PM
To: Rick Jones
Cc: Werner Hoehenrieder; netperf-talk at netperf.org
Subject: Re: [netperf-talk] Generating network traffic on a dual port NIC with a        single computer using netperf???

On Thu, 2010-12-09 at 17:07 -0800, Rick Jones wrote:
> Werner Hoehenrieder wrote:
> > I’m trying to use netperf to send out a traffic stream from one port of
> > a NIC card (10Gb/sec NIC)  to the other port of the card (dual port
> > 10Gb/sec NIC).
> >
> > I want to do this on a single computer –  not separate netserver and
> > netperf systems.
>
> You can't.  And the reason has nothing to do with netperf.  Virutally any TCP/IP
> stack out there "knows" which IP addresses are local to it, and will internally
> loopback traffic too/from those IPs without ever getting anywhere near a NIC,
> perhaps not even getting anywhere near the driver.
>
> There may be some patches to upstream Linux kernels to work around that, but
> unless you are running an upstream Linux kernel, that may not do you much good.

google for "+linux send to self"

some people have got it to work with some fancy netfilter rules too

Jesse
--
Jesse Brandeburg
This email sent via Evolution, powered by Linux