Hello!

I would like to know if it's possible to set the MAC-address on my
BroadCom ethernet NIC's. I would like to connect the two NIC's to
different switches and us spanning-tree. Therefor I need the same MAC
on the NIC's.

I'm using FreeBSD 5.

bge0: <Broadcom BCM5704C Dual Gigabit Ethernet, ASIC rev. 0x2002> mem 0xfcf20000
-0xfcf2ffff,0xfcf30000-0xfcf3ffff irq 16 at device 0.0 on pci2
bge0: Ethernet address: 00:0d:56:fe:c6:18
miibus0: <MII bus> on bge0
brgphy0: <BCM5704 10/100/1000baseTX PHY> on miibus0
brgphy0:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 1000baseTX, 1000baseTX
-FDX, auto
bge1: <Broadcom BCM5704C Dual Gigabit Ethernet, ASIC rev. 0x2002> mem 0xfcf00000
-0xfcf0ffff,0xfcf10000-0xfcf1ffff irq 17 at device 0.1 on pci2
bge1: Ethernet address: 00:0d:56:fe:c6:19

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Clarification of Question by flashz-ga on 18 May 2004 09:35 PDT

Hi!

Maybe I'm all wrong but as I understood it you would need two NIC's
with the same MAC when implementing Spanning-Tree. I re-question:

I would like to know how to best implement redudancy in FreeBSD with
the Broadcom NIC's (2). The server is connected to two switches witch
has two connections to the router. I want to make sure that if one of
the NIC's or one of the switches goes down it automaticly switches
over to the other NIC.

How is this possible ??

I am not sure what you are talking about but I will try to give it a shot.  
I am guessing you have a server with two NIC's.  And trying to connect
them with some redundancy on different switches in case one path goes
down.

If you give the NIC's the same mac ( I don't even think is possible)
but if you did you would have dup mac-address on your network.  And
your arp tables would be all wrong.

some switches are going to think the Mac address goes one way and the
others are going to think the same mac travels a different path. 
Every time they get a packet from one destination they will have to
update their table because more than likely its coming from a the
other nic now.  This could cause your connection to be little slower
because it is constantly updating the arp table for the same mac  and
in some instances sending packets the wrong way.
Spanning tree should not be a problem because Spanning-tree works with
BPDU this a packet the switch sends and allows the other switches to
see each other and then run an algorithm to prevent loops.  Un less
you are pruning the windows bridging protocol I would not worry about
the nic and spanning tree.  with the bridging protocol you r computer
could become a hub and pass traffic trough your machine therefore
causing a loop on the network.