Subject: Re: The impossible has happened.
To: David Gilbert <dgilbert@jaywon.pci.on.ca>
From: Matt Ragan <matt@ibmoto.com>
List: port-sparc
Date: 03/12/1996 22:05:36
David Gilbert wrote:
>
>	While testing ethernet things, I discovered that the
>impossible has happened.  I have two ethernet cards with the same
>ethernet (raw) address.  Actually, it's highly unlikely that this is
>true, but I get the following from my messages file (and on boot):
>
>Mar 11 23:49:05 repeat /netbsd: mainbus0 (root)
>Mar 11 23:49:05 repeat /netbsd: cpu0 at mainbus0: SUN-4/200 series (L64802 or ACT8847 FPU)
>Mar 11 23:49:05 repeat /netbsd: cpu0: 131072 byte write-back, 16 bytes/line, sw flush cache enabled
>Mar 11 23:49:05 repeat /netbsd: obio0 at mainbus0
>Mar 11 23:49:06 repeat /netbsd: ie0 at obio0 addr 0xf6000000 pri 6 address 08:00:20:06:ac:a6, type onboard
>Mar 11 23:49:06 repeat /netbsd: vmel0 at mainbus0
>Mar 11 23:49:06 repeat /netbsd: vmes0 at mainbus0
>Mar 11 23:49:06 repeat /netbsd: ie1 at vmes0 addr 0xffe88000 vec 0x75 pri 5 address 08:00:20:06:ac:a6, type multibus/vme
>
>	Now... I don't know if this is a causing a problem (my
>previously posted problems are reproducable without the two cards
>installed), but this certainly says something interesting about our
>driver.

No, this is perfectly normal for a Sun.  The Ethernet address is not contained
on the Ethernet card; it's contained within the PROM.  This is based on the
fairly safe assumption that one machine will not have two interfaces on
the same Ethernet segment.  The primary benefit is that you can swap cards
and not change the MAC address, which is primarily a benefit in diskless
machines that have to obtain an IP address based on the MAC address.

-- 
--------------------------------------------------------------------------
Matt Ragan  (matt@ibmoto.com)  Motorola/IBM Somerset PowerPC Design Center
Network Administrator          Systems/Network Engineering  (512) 795-7298
9737 Great Hills Trail         Austin, Tx  78759        FAX (512) 795-7519
--------------------------------------------------------------------------