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

[Greg Grotsky]

On Sun, Jan 10, 2010 at 11:37 AM, Frank Merrill <fmerrill1 at gmail.com> wrote:

> 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
>
>
Thanks for the response Frank.  I actually downloaded and played with
ethtool during my troubleshooting before RMA'ing the board.  It was set to
full-duplex and I tried to use ethtool to adjust the settings but for some
reason it wouldn't let me change anything.  I tried forcing to half-duplex,
I tried turning autoneg off, and I tried forcing to 100mbps or even 10mbps,
every time it told me that it could not set the values.  Oh well, we'll just
have to see what the new board brings.

-Greg
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