CODEWITHSUNDEEP
linux-kernellinux-device-driverembedded-linuxethernetu-boot
Amit Singh Tomar
Amit Singh Tomar

Reputation: 8610

Is eth0 only actual interface in Linux

I am confuse among various interfaces of ethernet .I am just going through this U-Boot Link

http://www.denx.de/wiki/DULG/UBootEnvVariables

Where it says

ethaddr: Ethernet MAC address for first/only ethernet interface (= eth0 in Linux).

Now my confusion is eth0 is only real interface whose address is programmed into efuse register

Is other interfaces like eth1 ,eth2 and so on virtula interface which will be configured by applcation later on .

Also from this link

http://e2e.ti.com/support/arm/sitara_arm/f/791/t/209421.aspx

Where it says

The MAC addresses programmed into the internal e-fuses will be from the TI address pool. Customer will need to add some type of storage device (Flash, EEPROM) which contains their MAC addresses if they want to use addresses from their own address pool.

Now are these two mac address one written in e-fuse and other in Flash by customer two different address for eth0?

Upvotes: 0

Views: 954

Answers (1)

Peter
Peter

Reputation: 14937

This uboot documentation is for many different kinds of hardware, some of which have only 1 interface, and some of which have more. The language "Ethernet MAC address for first/only ethernet interface (= eth0 in Linux)" just means that referenced variable is for eth0, which is the first ethernet interface. If there is only one interface, it is still called eth0. If your hardware has multiple ethernet interfaces, the other variables are for them.

Regarding the second question: it appears that this hardware device has a built-in ethernet controller, which needs a unique MAC address to function on a network. The device ships with a MAC address already configured (written into the e-fuse of the device, and therefore read-only). If you don't want to use that MAC address, you can instead use flash or EEPROM to store your own MAC address to configure the ethernet controller. Only one of those choices will be active.

One reason you might want to change the MAC address is that MAC addresses are assign in blocks to different vendors, and the shipped address is from the TI block. That means network analyzers will think the overall product is a TI device. If you want your product to appear as a different vendor, you need to use your own MAC address drawn from your own pool. If you don't know what this means, don't worry about it: use the one that is preconfigured and built-in.

Upvotes: 1

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