From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [net-next PATCH] igb: Use Intel OUI for VF MAC addresses Date: Fri, 11 Sep 2009 12:15:42 -0700 (PDT) Message-ID: <20090911.121542.45333246.davem@davemloft.net> References: <20090911014757.19631.66570.stgit@localhost.localdomain> <20090910190703.25d14533@nehalam> <1252638163.4355.35.camel@Joe-Laptop.home> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: shemminger@vyatta.com, jeffrey.t.kirsher@intel.com, netdev@vger.kernel.org, gospo@redhat.com, gregory.v.rose@intel.com, donald.c.skidmore@intel.com To: joe@perches.com Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:55826 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756044AbZIKTP0 (ORCPT ); Fri, 11 Sep 2009 15:15:26 -0400 In-Reply-To: <1252638163.4355.35.camel@Joe-Laptop.home> Sender: netdev-owner@vger.kernel.org List-ID: From: Joe Perches Date: Thu, 10 Sep 2009 20:02:43 -0700 > On Thu, 2009-09-10 at 19:07 -0700, Stephen Hemminger wrote: >> On Thu, 10 Sep 2009 18:48:27 -0700 >> Jeff Kirsher wrote: >> > From: Gregory Rose >> > This patch changes the default VF MAC address generation to use an Intel >> > Organizational Unit Identifier (OUI), instead of a fully randomized >> > Ethernet address. This is to help prevent accidental MAC address >> > collisions. > > I think this not a very good idea. > >> How can probability of collision be lower when the address space >> is smaller? If you are going to use Intel OUI, then you should constrain >> the selection to a portion of that space that is not being used >> by other hardware. I.e if you know Intel assigns addresses to their >> devices in ranges, choose a range that is not in use. > > Some other possibilities might be: I also completely agree that this patch is not a wise move.