Re: [LUG] NIC - full or half duplex?

[John Horne <J.Horne@xxxxxxxxxxxxxx>]

On 07-Sep-2001 at 16:13:13 Jon Still wrote:
> On Fri, 7 Sep 2001, John Horne wrote:
>> Quick question, does anyone know how I can tell if the network card in my
>> PC is running at full or half duplex? The card is an old 3c509 running
> 
> I'd imagine that this kind of thing is set with the driver options in
> /etc/conf.modules or modules.conf.
>
Good point. However the net-modules file only shows (for 3c509 cards):
3c509.c:
        io = 0
        irq = 0
        ( Module load-time probing Works reliably only on EISA, ISA ID-PROBE
          IS NOT RELIABLE!  Compile this driver statically into kernel for
          now, if you need it auto-probing on an ISA-bus machine. )         

Nothing about the duplex.

> ifconfig certainly won't tell you - try looking through your dmesg
> output.
>
Yes, dmesg shows the card being autoconfigured, but again not the duplex:
eth0: 3c509 at 0x300 tag 1, 10baseT port, address  00 a0 24 6d 35 ac, IRQ 10.
3c509.c:1.16 (2.2) 2/3/98 becker@xxxxxxxxxxxxxxxxxxxxx

> However, I seem to remember that full duplex only works in a switched
> environment.
>
The reason for asking is that the entire Uni is having a new infrastructure
put in. It is centered around an ATM ring (as before) with gigabit switches,
and a whole bunch of other switches around the place. Previously the default
configuration was 10Mbit half-duplex. Now the default is 100Mbit,
full-duplex. Hence I'd like to know If my card can run at full-duplex. Sure
we could set the port to fdx, and see what happens, but I thought it would
be better if there was a command that said something simply like 'you have a
3c509 card running at 10Mbps, half-duplex'. Being able to set full-duplex as
well would be even better :-) It could well be that I need to take the PC
cover off and look at the card for switches - okay, I'm guilty of being lazy
about that one before asking the question :-) However, I think the overall
answer is that there is no such command.

On 07-Sep-2001 at 20:19:49 Mark Evans wrote:
> Best way is to look at the lights on the switch,
>
I don't install the switches - no idea where it is :-)

> also check in /var/log/messages
>
Nope, but dmesg does show some info.

One other suggestion was the 'mii-tool' command. However this works with
100/10Mbps capable cards, which mine isn't.

Thanks,

John.

------------------------------------------------------------------------
John Horne, University of Plymouth, UK           Tel: +44 (0)1752 233914
E-mail: jhorne@xxxxxxxxxxxxxx
PGP key available from public key servers
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