On Tue, Apr 24, 2007 at 12:20:12PM +0100, David Lee wrote:
> On Tue, 24 Apr 2007, Dejan Muhamedagic wrote:
> 
> > On Mon, Apr 23, 2007 at 06:56:55PM +0100, Faisal Shaikh wrote:
> > > Both cards on each machine(Sun Netras) have the same MAC addresses. Can 
> > > this be a cause of the problem?
> > >
> > > fw1 ha.d # lspci | grep Ethernet
> > > 01:01.1 Ethernet controller: Sun Microsystems Computer Corp. Happy Meal 
> > > (rev 01)
> > > 01:03.1 Ethernet controller: Sun Microsystems Computer Corp. Happy Meal 
> > > (rev 01)
> > >
> > > fw1 ha.d # dmesg | grep Ethernet
> > > Ethernet address: 08:00:20:c2:d5:3e
> > > eth0: HAPPY MEAL (PCI/CheerIO) 10/100BaseT Ethernet 08:00:20:c2:d5:3e
> > > eth1: HAPPY MEAL (PCI/CheerIO) 10/100BaseT Ethernet 08:00:20:c2:d5:3e
> >
> > what!? shouldn't each device have a unique mac address? never seen
> > anything like this. perhaps you should ask your hw vendor about
> > this.
> 
> (I'm a little rusty on this, but I hope what follows is broadly correct.)
> 
> Sun hardware traditionally does do this.  The location of the MAC address
> is primarily in the boot prom of the machine, rather than in the ethernet
> device itself, and that prom-based MAC address is then applied to all the
> ethernet interfaces.  Thus the observed:
>    eth0: ... 08:00:20:c2:d5:3e
>    eth1: ... 08:00:20:c2:d5:3e
> 
> of the same MAC on multiple interfaces is normal, and expected, for Sun
> hardware.

Interesting practice. Thanks for the info.

> (Drifting off topic....)
> 
> Historically, the multiple interfaces tend to be on separate subnets (as
> in simple routing) where using the same MAC isn't a problem.  (Concepts of
> "ethernet bonding", "link aggregation" (etc.) of multiple interfaces are
> relatively new and would require a little extra configuration to achieve
> on default Sun hardware.)

Right, that's not a problem for the wire protocols since things
are done on a per interface/network basis. However, sometimes,
it's convenient to use the MAC as a unique software. I think I
did that myself too.

> 
> Hope that helps.
> 
> 
> -- 
> 
> :  David Lee                                I.T. Service          :
> :  Senior Systems Programmer                Computer Centre       :
> :  UNIX Team Leader                         Durham University     :
> :                                           South Road            :
> :  http://www.dur.ac.uk/t.d.lee/            Durham DH1 3LE        :
> :  Phone: +44 191 334 2752                  U.K.                  :
> _______________________________________________
> Linux-HA mailing list
> [email protected]
> http://lists.linux-ha.org/mailman/listinfo/linux-ha
> See also: http://linux-ha.org/ReportingProblems

-- 
Dejan
_______________________________________________
Linux-HA mailing list
[email protected]
http://lists.linux-ha.org/mailman/listinfo/linux-ha
See also: http://linux-ha.org/ReportingProblems

Reply via email to