Friday, September 16, 2005

ether address on multi-port cards

ether address on multi-port cards

Why is the ethernet address the same for every port on a multiport
ethernet card, and what are the implied consequences of this?
Specifically the 4 bge interfaces in a V210, or the 4 ce interfaces on a
quad gigaswift.

The system gets this hardware address from the EEPROM not from the
ethernet hardware.

> The system gets this hardware address from the EEPROM not from the
> ethernet hardware.

not default on the v210, as it has:
local-mac-address?=true
try # eeprom local-mac-address?=true
if you want quads to have different addresses.

v210: # ifconfig -a
lo0: flags=1000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4> mtu 8232 index 1
inet 127.0.0.1 netmask ff000000
bge0: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 1500 index 2
inet 137.58.166.251 netmask ffffff00 broadcast 137.58.166.255
ether 0:3:ba:da:a8:8f
bge1: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 1500 index 3
inet 137.58.167.251 netmask ffffff00 broadcast 137.58.167.255
ether 0:3:ba:da:a8:90
bge2: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 1500 index 4
inet 137.58.168.251 netmask ffffff00 broadcast 137.58.168.255
ether 0:3:ba:da:a8:91
bge3: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 1500 index 5
inet 137.58.169.251 netmask ffffff00 broadcast 137.58.169.255
ether 0:3:ba:da:a8:92

/j├Ârgen

>Why is the ethernet address the same for every port on a multiport
>ethernet card, and what are the implied consequences of this?
>Specifically the 4 bge interfaces in a V210, or the 4 ce interfaces on a
>quad gigaswift.

That's because the PROM programs them that way; there are no supposed
consequences as generally you don't have all cards in the same
domain.

But all of our current interfaces have on-board private mac addresses
you can use by setting:

eeprom local-mac-address?=true

and then rebooting.

The qfe cards have a "local-mac-address" property (and from the
looks of it, so do many other cards) which reveals their
programmed mac-address even if booted with local-mac-address?=false

prtconf -vp | grep local
local-mac-address?: 'true'
local-mac-address: 0003ba30.c0f4
local-mac-address: 0003ba30.c0f5
local-mac-address: 0003ba30.c0f6
local-mac-address: 0003ba30.c0f7
local-mac-address: 080020a9.f67e

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