Xircom 10/100 Network Card and 3Com 10/100 Base-TX

Scott Mitchell scott.mitchell at mail.com
Wed Dec 13 22:08:55 GMT 2000

On Wed, Dec 13, 2000 at 07:41:10PM +0000, Mike Bristow wrote:
> (you might also consider changing "media 100baseTX" to "media
> 100baseTX mediaopt full-duplex" in either the ifconfig_xe0 or media
> "..." bits also)

In general, yes, but the Xircom cards don't do full duplex at 100Mbps :-(
so that won't work...

Media negotiation is a known problem with the xe driver -- according to the 
guy at Xircom I talked to when I was getting the card specs, they do
something slightly non-standard and undocumented here.  I wrote the driver
to do autonegotiation pretty much the same way that the Linux driver and
most of the other FreeBSD drivers do it; as you can see it doesn't always
work.  I've had the same problem with Cisco and 3Com hubs/switches at my
two previous workplaces -- sometimes it would autonegotiate 100baseTX
successfully, sometimes it would fall back to 10baseTX.

The problem seems to be worse with some hubs, but I haven't been able to
discern any real patterns yet.  Taking the interface down then bringing it
back up again (ifconfig xe0 down; ifconfig xe0 up) will often bring about a 
succussful negotiation.  Otherwise, forcing the media type generally works.

If anyone has any ideas on how to fix this, I'm all ears!  Even just the
particular models of hub/switch the driver does/doesn't successfully
negotiate with would be useful.


Scott Mitchell          | PGP Key ID | "Eagles may soar, but weasels
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