[CALUG] Random Network Interfaces

[Rajiv Gunja]

On Wed, Mar 23, 2011 at 23:38, Bryan J Smith <b.j.smith at ieee.org> wrote:

> From: Rajiv Gunja <opn.src.rocks at gmail.com>
> > Summary: What you see on Linux is normal behavior for Linux,
> > HP-UX, AIX, Irix and Solaris.
>
> Not quite.
>
> With HP-UX, HP controls the PA-RISC platform.
> With AIX, IBM controls the POWER platform.
> With Irix, SGI controls the MIPS and IA-64 platforms.
> With Solaris, Sun controls the Sun platforms.
>
> >>>> Guess you did not read what I wrote. In all the above Operating
Systems, irrespective of the platform, the hardware name once assigned will
not change unless you move the physical location of the network card or
peripheral, on their respective bus. This is true even on convexOS and
OSF/1.

>>>> By the way, Linux distros are available on SPARC, IA-64, MIPS and POWER
platforms and it behaves exactly the same way. Granted that each platform
will have its own way of naming the peripheral depending the driver and
kernel module.


> Unfortunately for Linux, it does _not_ control the PC platform.  Especially
> not
> with the legacy PC BIOS (EFI might be another story).
>
> >>>> What in the world does "_not_control" mean? OSes do not control the
hardware. OSes are interfaces to the hardware. Kernel of each OS scans the
hardware in whatever order and presents it to the OS/applications. Yes there
are helpers to each platform: eeprom, bios, etc. But the underlying
principle is the same.

>>>> Same thing goes for EFI, it too is an interface for the underlying
hardware. If the OS is EFI aware, then it makes use of it. Of course that
seems redundant as none other than OSX seem to use it at the moment.


> So when it comes to assigning devices to names, it's not exacting by
> default,
> because of how the PC can rescan/reorder things.
>
> >>>> Isn't that what I said? each OS will perform a scan in a certain order
and that remains constant, that is why we were able to install images on our
Dell servers without having to look at each hardware to see if the OS
assigned eth0 or eth2 for the first network interface. (Solaris eeprom scans
the last bus first)

Fortunately, if you set the MAC in the ifcfg-(device) files (under
> /etc/sysconfig/network-scripts) on a Fedora-based system, you will always
> get
> that MAC assigned to the (device).  That is how it has been since around
> Fedora
> Core 4 or so. To tie down other hardware assignments, udev is utilized,
> such as
> for fixed disks.
>
> >>>> I would not suggest changing mac address, unless you are sure that
there will be no other machine with the same address. Plus I do not see a
point to changing mac address, as it is unique to each network card
manufactured around the world.

>
> --
> Bryan J  Smith       Professional, Technical Annoyance
> Linked Profile:     http://www.linkedin.com/in/bjsmith
> ------------------------------------------------------
> LS3 Z51:  When you absolutely, positively need to pass
> that "Smart Car" by accelerating 60-100mph in 3rd gear
> in around 4s so you can shift back to 6th gear and get
> the same 30mpg at 75mph he struggles to get at 65mph+.
>
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