Subject: [rbridge] Global MAC Addresses

From: erik.nordmark at sun.com (Erik Nordmark)
Date: Fri, 09 Mar 2007 16:06:11 -0800

Eric Gray (LO/EUS) wrote:

> 	Interstingly enough, I am really sure that the IPv6 folks 
> have looked at this before.  And I am also sure that at least one
> suggested solution has been considered.  I do not know if any (of
> possibly many) proposals were actually adopted but, if none were,
> it would be because the IPv6 people did not see this as a problem.

AFAIK the IPv6 folks have not considered this.
But as you pointed out, the global IPv6 addresses would still be 
globally unique since they would have different subnet prefixes.

The only issue for IPv6 is that this (and host-side virtualization in 
general) means that the the semantics of the universal bit in the 
modified EUI-64 format is even weaker than before.
But there is no protocol to date which assumes anything about the 
semantics of this bit. As RFC 4291 says:

    The use of the universal/local bit in the Modified EUI-64 format
    identifier is to allow development of future technology that can take
    advantage of interface identifiers with universal scope.

   Erik