manufacturing convention for mapping macs to ether?

RouterOS General
1

Hello,

Is there a convention in manufacturing for mapping mac addresses to ethernet ports?

e.g., if the macs are

[vaden@Ombudsman] > /interface ethernet print
Flags: X - disabled, R - running

NAME MTU MAC-ADDRESS ARP

0 R local 1500 00:0C:42:09:30:12 enabled
1 R public 1500 00:0C:42:09:30:13 enabled
2 R ether3 1500 00:0C:42:09:30:14 enabled

Is it more or less guaranteed that :12 is ether1?

rgds/ldv

2

Not quite sure what you’re talking about :confused:

Each NIC has a unique MAC address, that MAC never change. So, :12 will always be the same physical card in the machine yes.

Will :12 always be Ether1 in your MT? Yes, unless you change the PCI slot in which the card is inserted.

Linux populates Ether0…EtherX in the order in which it is detected on the motherboard. First the PCI bus is scaned from slot 0 to slot X, then the ISA bus (if you have one).

So if you switch two cards arround in the PCI slots on the motherboard they will also switch in naming in the MT. This means that :12 (now Ether1), will remain :12, but on Ether2 for example

3

Agreed; I should have stated that the hardware environment is RB532.

rgds/ldv

4

Well you can’t swop the cards out can you? So they remain connected to the same location on the PCI bus…

:12 will always stay on the same “named” interface.

5

The question is whether one can count on the lower numbered mac being either ether1 or ether3 and everything else being monotonic, …

My guess is that is the case, but it would be good if someone who knows that to be the case chimes in (Normands?).

rgds/ldv

6

are you asking if their is a pattern to the placment of nic’s in routerboards??

i can say this on a RB i just connected to:

eth1= 00:0x:xx:xx:51:15

eth2 = 00:0x:xx:xx:51:16

eth3= 00:0x:xx:xx:51:17