[mythtv-users] Zotac IONITX-B-E Network Issues

Frank Merrill fmerrill1 at gmail.com
Sun Jan 10 18:37:49 UTC 2010


On Thu, Jan 7, 2010 at 2:48 AM, Greg Grotsky <spikeygg at gmail.com> wrote:
> Just purchased one of these bad boys from newegg and I'm getting lots of
> prebuffering pauses while watching videos streamed from the backend.  I
> noticed that the pauses only occur during network streaming activity, if I
> rewind the video and play it (from cache) it's perfect.  Then I noticed that
> ifconfig was reporting significant amounts of errors (22389!):
>
> eth0      Link encap:Ethernet  HWaddr 00:01:2e:26:4f:97
>           inet addr:192.168.0.100  Bcast:192.168.0.255  Mask:255.255.255.0
>           inet6 addr: fe80::201:2eff:fe26:4f97/64 Scope:Link
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:1445943 errors:22389 dropped:0 overruns:0 frame:22389
>           TX packets:970314 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:1000
>           RX bytes:1918270735 (1.7 GiB)  TX bytes:81217659 (77.4 MiB)
>           Interrupt:21 Base address:0x2000
>
> The error number skyrockets as I watch a video (especially while it is
> giving me prebuffering pauses).  I have a usb-to-ethernet device and using
> the same cat5e cable on this usb ethernet port results in smooth, error-less
> transmissions.  It's looking like this is a problem with my specific
> motherboard.  Has anyone else with one of these Zotac IONITX deals seen
> anything like this?  I'd hate to return it only to have the same issue, I'd
> like to find out that it's something in my configuration.
>
>

I see that you have already RMA'd this board.
One thing I would have made certain of is that you don't have a Duplex mismatch.
I'm guessing that on the ZOTAC board the network tools are setting the
interface to Autonegotiation or Full-duplex.
You can use 'ethtool eth0' to see what it is currently set to.

In any case, if that interface is trying to autonegotiate, but your
switch doesn't do that (or maybe doesn't do it properly) you could
have a duplex mismatch.
If a 100Mbs interface on the switch is trying to autonegotiate, but it
can't, it would, by standards, fall back to the default of
100/Half-duplex.
If the switch is for whatever reason setting itself to
100/Half-duplex, then you would get the errors you are seeing, and
they would increment a lot more rapidly under higher loads.  This
would occur if the Zotac was at 100/FD and the switch could have some
of it's transmit traffic 'stepped on' by the Zotac, causing frames
that are damaged in some way.
The Zotac would then see those frames as being receive errors.
Basically if one side is not the same as the other, you will see
errors on at least one end.
So, what this comes down to is that if you have the same issues on the
new board, then maybe the problem is the switchport being at
Half-duplex.
Whether you can change that on your switch or not, I have no idea.
If your USB adapter doesn't show the issue, maybe it is running at
Half-duplex, or maybe it is autonegotiating correctly with the switch
port?

Of course, it most definitely could still have been the hardware on the board.
Almost all such cases I have seen in 22 years have been
non-intentional mis-configuration.
If the problem does recur, you can always try checking the Zotac
interface, and if it is set to Full-duplex, instead set it to
Half-duplex and see if the issue ceases.  If so, then you may want to
see if the switch is configurable to get both sides at Full-duplex.

Here's hoping you get the new board and it 'Just Works'.

Frank


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