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On Fri, 13 Jan 2006, Arne R. van der Heyde wrote:
> I am trying to connect two identical MSI K8N Neo4-F servers with NVIDIA
> nForce4 gigabit Lan ports. When the two ports are connected together via
> a crossover cable, neither computer is able to detect a carrier on the
> Lan ports and are not able to communicate. When either of the nForce4
> gigabit port is connected to a Lan port on another computer with a
> different Lan hardware or to a port on a switch the forcedeth drivers
> detect a carrier and are able to communicate.
>
You need to use the correct kind of cross-over cable for the Gigabit
ports. Then, you need to set both ports manually because there
is no hardware (the switch) to handle the auto-configuration. The
default is usually `autoneg on`. This tells the switch to
auto-configure. Connected to another port, not a switch, this
means nothing and the device remains dormant.
You do this with `ethtool`. Set both to full-duplex and they should
work. Also, there is no "carrier". This is all multi-phase NRZ.
> It appears that the nForce4 Gigabit ports are not generating a carrier.
> Does the nForce4 not provide standard ethernet ports? If they are
> standard ethernet ports, how do I tell forcedeth to generate a carrier?
> Also how do I get forcedeth to run at a Gigabit?
>
> Thanks for any help,
>
> Best regards,
> Arne R. van der Heyde
> [email protected]
>
> Summit Instruments Inc.
> 2236 N. Cleveland-Massillon Rd.
> Akron, Ohio 44333-1255 USA
>
> Phone (330)659-3312
> Fax (330)659-3286
> http://www.summitinstruments.com
>
>
Cheers,
Dick Johnson
Penguin : Linux version 2.6.13.4 on an i686 machine (5589.54 BogoMips).
Warning : 98.36% of all statistics are fiction.
.
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Thank you.
"linux-os \(Dick Johnson\)" <[email protected]> writes:
> You need to use the correct kind of cross-over cable for the Gigabit
> ports.
Correct, with all pairs crossed.
I don't force-death but I think most gigabit cards (and some 100BaseTX)
work with plain cable as well (using auto MDI-X, and auto-polarity
if needed).
> Then, you need to set both ports manually because there
> is no hardware (the switch) to handle the auto-configuration. The
> default is usually `autoneg on`. This tells the switch to
> auto-configure. Connected to another port, not a switch, this
> means nothing and the device remains dormant.
Again, I don't know nforce, but normal cards with autonegotiation
(i.e., (almost?) all 100BaseTX and newer) can negotiate speed and
duplex without need for a switch. BTW from net POI switches and
cards are DTEs, there is no special distinction WRT autonegotiation.
--
Krzysztof Halasa
On Fri, Jan 13, 2006 at 01:37:14PM -0500, Arne R. van der Heyde wrote:
> I am trying to connect two identical MSI K8N Neo4-F servers with NVIDIA
> nForce4 gigabit Lan ports. When the two ports are connected together via
> a crossover cable, neither computer is able to detect a carrier on the
> Lan ports and are not able to communicate. When either of the nForce4
> gigabit port is connected to a Lan port on another computer with a
> different Lan hardware or to a port on a switch the forcedeth drivers
> detect a carrier and are able to communicate.
Gigabit does NOT use cross over cables. You connect gig ports with a
normal ethernet cable at all times unless you are connecting to a 10 or
100mbit port at the other end. When running at gigabit speed, there are
4 pairs of wire in use with full duplex on all 4 pairs. 10 and 100mbit
have a single pair for data each way, and hence need the cross over when
not connecting to a switch/router.
> It appears that the nForce4 Gigabit ports are not generating a carrier.
> Does the nForce4 not provide standard ethernet ports? If they are
> standard ethernet ports, how do I tell forcedeth to generate a carrier?
> Also how do I get forcedeth to run at a Gigabit?
Hopefully using the right cable type will solve the problem.
Len Sorensen
Lennart Sorensen wrote:
> Gigabit does NOT use cross over cables.
I don't think this is always true. Some gigabit ports can autosense
polarity and are able to use standard cables. Others require gigabit
crossover cables.
Chris
On Fri, Jan 13, 2006 at 04:38:13PM -0600, Christopher Friesen wrote:
> Lennart Sorensen wrote:
>
> >Gigabit does NOT use cross over cables.
>
> I don't think this is always true. Some gigabit ports can autosense
> polarity and are able to use standard cables. Others require gigabit
> crossover cables.
Hmm, it appears you are right. I have never seen a non autosensing
gigabit port, so I thought it was part of the spec. Given the pairs all
send and receive already it seemed like an obvious part to include in
the spec.
Certainly a cross over cable made for 10/100 mbit won't work. It needs
the other two pairs swapped to. Most store bought cross over cables
seem to only have 10/100mbit in mind when they were made.
Proper pinout appears to be:
1 <-> 3
2 <-> 6
4 <-> 7
5 <-> 8
Len Sorensen