[c-nsp] NPE-G1s don't want to talk to each other over copper?

[Gert Doering]

Hi,

On Wed, Mar 19, 2014 at 05:45:45PM +0100, Lukas Tribus wrote:
> >> should work fine. Manually set the interface media type on both sides to
> >> be rj-45, and make sure that the cable is a cross-over gigabit:
> > 
> > I wonder. Shouldn't this never be needed for Copper Gbit?
> 
> Its correct that GigabitEthernet mandates autoneg, and it is also correct
> that "mdix auto" REQUIRES autoneg, but afaik that doesn't mean all your
> gigabit/autoneg gear can also automatically do auto-mdix, because that
> probably requires different hardware (switching RX/TX).

There is nothing to "switch".  GigE on copper will use all 4 pairs *in both
directions at the same time*, unlike 10/100 (2 pairs, with one for RX only
and one for TX only).

There is something to negotiate - who is master, who is slave, and which
pair on side A goes to which pair on side B.

gert
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Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de
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