Switching between half-duplex and full duplex

[Rudolf Cejka]

Pang wrote (2007/06/03):
>  I have just installed FreeBSD and found that the nic em0 is set to 
> half-duplex only. Could anyone tell me how I can switch it to full-duplex?
> em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>        options=b<RXCSUM,TXCSUM,VLAN_MTU>
>        inet 172.16.0.2 netmask 0xfffffffc broadcast 172.16.0.1
>        ether XX:XX:XX:XX:XX:XX
>        media: Ethernet autoselect (10baseT/UTP <half-duplex>)
>        status: active

Hello, so I was right? ;o) I assume, that you have more capable device
on the other side, atleast 100 Mb/s full-duplex. In that case, you should
check, what connection type is "seen" on the other side (switches with
management!). Then you can check auto-negotiation settings on the other
side, try to change ethernet cable - it would be faulty and auto-neg would
not work correctly, then look, which chipset do you have - the driver would
not work with too new chips, I have here some ICH8 machines, which do work
just 100 Mb/s instead of 1 Gb/s (I expect that -current should work now).

Regards.

PS: Another very good command is ifconfig -m em0, where you can see all
allowed media/mediaopt combinations.

-- 
Rudolf Cejka <cejkar at fit.vutbr.cz> http://www.fit.vutbr.cz/~cejkar
Brno University of Technology, Faculty of Information Technology
Bozetechova 2, 612 66  Brno, Czech Republic