[vortex] 3c905C: Packet losses, but only with a switch (2nd , part)

[Giuseppe Ciaccio]

On Tue, 4 Jul 2000, Bogdan Costescu wrote:

> On Tue, 4 Jul 2000, Giuseppe Ciaccio wrote:
> 
> > But the packet loss persists :(
> 
> How do you observe the packet loss? And how many packets are lost?

I use "ping -f".  My machines are fast enough to absorb it.

> 
> > And, even worse, it now occurs also with a crossover cable, as well as
> > with a repeater hub.
> 
> What does mii-diag report in these cases?

N-WAY autoneg is enabled on both NICs.

With crossover cable as well as repeater hub, mii-diag reports:

Basic registers of MII PHY #0:  0000 0000 0000 0000 0000 0000 0000 0000.
 Basic mode control register 0x0000: Auto-negotiation disabled, with
 Speed fixed at 10 mbps, half-duplex.
 Basic mode status register 0x0000 ... 0000.
   Link status: not established.
 Link partner information information is not exchanged
when in fixed speed mode.

Strange enough, it reports 10 Mbps while the NIC led is on 100 Mbps.

> 
> > My feeling is that the autoneg is somehow broken in the 3c905C cards.
> 
> I'm using quite a lot of them and never had problems (after setting them
> to "HAS_NWAY")...
> 
> > When enabled, it fails when connecting to non-negotiating devices (like the
> > crossover cable and the repeater hub).  
> 
> I have used this (by forcing the switch to 100-FD and 100-HD) and the card
> always went to the right mode. And with the crossover cable, it has also
> an autonegotiating partener as the cable does nothing WRT this; or you
> tried to connect to a card with forced speed?

Both NICs were autonegotiating.

> 
> > When disabled, it somehow still tries to work (with odd results) when
> > connecting to a negotiation-capable device (like my switch), even if the
> > device is instructed not to negotiate.
> 
> For me it also worked, both devices being set to either 100-FD or
> 100-HD...
> I have 3C905C cards and a BayStack 350-24T switch.

I will try to disable the switch flow ctl and let you know.
But it is strange, however, that things are bad with a crossover cable
when autoneg is enabled.  There shouldn't be any flow ctl in this case,
and the two NICs should negotiate for 100 Mbps full-duplex.

Giuseppe

Giuseppe Ciaccio               http://www.disi.unige.it/person/CiaccioG/
DISI - Universita' di Genova   via Dodecaneso 35   16146 Genova,   Italy
phone +39 10 353 6638          fax +39 010 3536699 ciaccio@disi.unige.it
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