[Server-devel] Is a USB-Ethernet NIC appropriate for the XS?

Bryan Berry bryan at olenepal.org
Mon Mar 23 23:49:04 EDT 2009

The ever helpful cjb and Mitch_Bradley directed me to the root of the
problem, the USB-ethernet devices I am using are USB 1.1 which has
horrible throughput. A USB-ethernet device that supports USB 2.0 should
fix the problem.

<BryanWB> Mitch_Bradley: great, do u think I can buy a usb2 ethernet nic
for under $50? budget is tight and I need these for 15 XS's
<Mitch_Bradley> AX8817X and AX88772 are the chips
<BryanWB> Mitch_Bradley: thanks
<BryanWB> Mitch_Bradley: is there any reason that USB-Ethernet is
inherently unworkable or is it just a question of getting the right
usb-ethernet nic?
<Mitch_Bradley> USB 1.1 sucks rocks for ethernet because the polling for
rx packets kills the throughput
<cjb> BryanWB: no, the others are usb2
<cjb> what Mitch_Bradley said
<BryanWB> Mitch_Bradley: so usb1.1 will totally crap out w/ 20 users ?
<Mitch_Bradley> USB2.0 has much improved bandwidth and much lower
latency for polling
 usb1.1 will totally crap out with 1 user
<BryanWB> Mitch_Bradley: thanks a lot guys, you are saving my bacon
<cjb> BryanWB: the number of users won't affect it, other than by
sucking proportional to load
<Mitch_Bradley> I didn't even bother supporting USB 1.1 ethernet chips
in OFW.  It's just not worth it.
<cjb> anyway, yeah.  just find an asix dongle.
<Mitch_Bradley> try to buy a name brand device.  The no-name ones often
just don't work.

On Mon, 2009-03-23 at 15:43 +0100, Martin Langhoff wrote:
> On Mon, Mar 23, 2009 at 3:10 PM, Bryan Berry <bryan at olenepal.org> wrote:
> > We want to use the MSI Wind PC for the XS but it has one big problem. It
> > only has 1 on-board NIC and no PCI slots. As you know, the XS requires 2
> > NIC's. We have tried several different USB NIC's and are having serious
> > throughput problems. Is this issue one w/ the NIC or the fact that it is
> > connected by USB?
> My main worry with USB-connected NICs would be reliability. If the NIC
> is reliable, but the throughput a bit below-par, you can still
> probably use it as the WAN NIC -- the throughput is likely to be
> constrained upstream anyway.
>  - When you say throughput problems... what are you getting? How bad
> is it? Even if limited, would it be appropriate for the WAN port?
>  - The problem may be specific to the driver or NIC hardware -- is
> there any discussion on the kernel dev list about it?
>  - The problem may be with the USB bus on the MS Wind, hardware or
> drivers. Perhaps testing for bus throughput or interrupt handling
> helps?
>  - Have you tested the reliability of the devices? This may be a larger problem.
> cheers,
> martin
Bryan W. Berry
Technology Director
OLE Nepal, http://www.olenepal.org

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