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From: Olivier Nicole <on@cs.ait.ac.th>
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Subject: Re: howto determine network device unit number? device.hints?
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Hi,

Sorry to jump in but...

> Problem is, this unit number is not constant and changing arbitrarily every
> time I reload the driver (card A unit number=0 & card B un=1 or the other
> way around).

Since I have been using FreeBSD, the NIC had always been given the
same unit number (that is, unless I play and swap the hardware inside
the machine).

And that is the normal behaviour. Of course at each boot the interface
em0 remains interface em0 and ithe interface em1 remains interface
em1, else it would be a headache.

> Plus, I still don't understand why the unit number should change at all,
> instead of being determined according to the card PCI location or some other
> constant.

Not only it should not change, but you are the first person I ever see
mentioning that it change at each boot.

Bests,

Olivier