Re: carrier (network card)

Donald Becker (becker@cesdis1.gsfc.nasa.gov)
Fri, 24 Dec 1999 18:04:12 -0500 (EST)


On Thu, 23 Dec 1999, Catalin BOIE wrote:

> What means "frame" and "carrier" for a interface?

They are type of errors.
They should never occur on a properly working network.

> I have many carrier errors on a 3COM.
> What's going on?

You likely have a cabling problem, or a duplex mismatch.
Most cabling problems are mispaired cables.
Most duplex mismatches are caused by forcing one end of a link to full
duplex.

You should always let the link the autonegotiated the duplex. If you have
old or broken equipment that fails to negotiated duplex, leave it at half
duplex. The minor additional performance of forced full duplex is not worth
the long-term problems.

Use 'mii-diag' to check the link status.
http://cesdis.gsfc.nasa.gov/linux/diag/index.html

> eth0: 3Com 3c905B Cyclone 100baseTx at 0xe400, 00:50:04:56:92:f2, IRQ 11
> 8K byte-wide RAM 5:3 Rx:Tx split, autoselect/Autonegotiate interface.
> MII transceiver found at address 24, status 782d.

A few 3c905B cards had transceivers that defaulted to a bad setting, and
needed the driver to change the configuration. The 3Com-written driver has
this work-around. The errors were *very* rare, so it's unlikely that this is
your problem.

Donald Becker
Scyld Computing Corporation, and
USRA-CESDIS, becker@cesdis.gsfc.nasa.gov

-
To unsubscribe from this list: send the line "unsubscribe linux-net" in
the body of a message to majordomo@vger.rutgers.edu