parallel detect failing

parallel detect failing

Post by Noah David » Thu, 03 Jul 2003 22:30:32



I just ran into a problem where I troubles getting link to come up. I have a
10/100 card configured for auto-negotiate connected to a switch. When the
switch port was configured as fixed 100/full duplex link would not come up.
When the switch port configured for auto then I did get link to come up at
100. Since policy is that switch ports are configured for specific speeds
and duplex values we could not leave the switch port set to auto.

I fixed the problem by power cycling the system the card was in.

My question is what could cause the card to fail to detect the speed of the
switch when it was set to a fixed speed but to still auto-negotiate
correctly and why would a power cycling fix the problem?

--
Noah Davids
Serendipity is a function of bandwidth

Web:      http://members.cox.net/~ndav1

 
 
 

parallel detect failing

Post by Stuart Robins » Thu, 03 Jul 2003 23:05:00


Quote:> When the
> switch port was configured as fixed 100/full duplex link would not come
> up

You should not do that if your connecting devices set to auto to the port.

If everything worked as designed, the PC set to auto should use the
parallel detect function to sense the speed (100Mbs) and will set itself
to HD, you now have a duplex mismatch between PC and Switch, not good.

Stuart.

 
 
 

parallel detect failing

Post by Noah David » Thu, 03 Jul 2003 23:28:12


No the card has a separate settings for speed and full/half duplex and was
configured for full duplex. It was only the speed that wasn't working. By
the way we also tried the switch port at 10 mbps full duplex and that also
failed to bring up link. The chip just didn't seem to wait to do parallel
speed detection at all.


Quote:> > When the
> > switch port was configured as fixed 100/full duplex link would not come
> > up

> You should not do that if your connecting devices set to auto to the port.

> If everything worked as designed, the PC set to auto should use the
> parallel detect function to sense the speed (100Mbs) and will set itself
> to HD, you now have a duplex mismatch between PC and Switch, not good.

> Stuart.

 
 
 

parallel detect failing

Post by Stuart Robins » Thu, 03 Jul 2003 23:55:00


Quote:> No the card has a separate settings for speed and full/half duplex and
> was configured for full duplex.

Well you have me confused now, in you first post you said;

Quote:> I have a 10/100 card configured for auto-negotiate connected to a
> switch.

The two seem to be contradictory.

But that aside if your forcing the switch end to 100FD, why dont you force
the other end to 100FD also, and what happens if you do ?

Stuart.

 
 
 

parallel detect failing

Post by Noah David » Fri, 04 Jul 2003 10:26:14


We can configure the speed and duplex values that the card will advertise
via auto-negotiation. In this case we told the card to advertise ONLY 100
mbps and full duplex. Unfortunately, we can't tell the card to skip the
autonegotiate phase. It will always try to autonegotiate before trying the
parallel detect. In this case it seemed to not try to parallel detect, at
least until we power cycle it.

After looking at this some more I think I have convinced myself that we had
a failure of the driver and not the chip. The driver is proprietary (ours)
so I have no one to complain to.


Quote:> > No the card has a separate settings for speed and full/half duplex and
> > was configured for full duplex.

> Well you have me confused now, in you first post you said;

> > I have a 10/100 card configured for auto-negotiate connected to a
> > switch.

> The two seem to be contradictory.

> But that aside if your forcing the switch end to 100FD, why dont you force
> the other end to 100FD also, and what happens if you do ?

> Stuart.

 
 
 

parallel detect failing

Post by Stuart Robins » Fri, 04 Jul 2003 15:21:00


Quote:> We can configure the speed and duplex values that the card will
> advertise
> via auto-negotiation. In this case we told the card to advertise ONLY
> 100
> mbps and full duplex

That makes more sense, though I cant recall seeing a driver that allowed
this before.

Quote:>  Unfortunately, we can't tell the card to skip the
> autonegotiate phase. It will always try to autonegotiate before trying
> the
> parallel detect.

How unusual, more useful to be able to force the card to a particular
setting than control what it advertises.

Quote:> After looking at this some more I think I have convinced myself that we
> had
> a failure of the driver

Sounds an unusual driver .......

Stuart.

 
 
 

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- Ben


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