[e2e] [mycroft@MIT.EDU: Re: use of MAC addresses]

Charles M. Hannum mycroft at netbsd.org
Thu Apr 13 17:17:28 PDT 2006


Whoops, fired from the wrong address before.

----- Forwarded message from "Charles M. Hannum" <mycroft at MIT.EDU> -----

Return-Path: mycroft at MIT.EDU
Received: from po12.mit.edu ([unix socket])
	by po12.mit.edu (Cyrus v2.1.5) with LMTP; Thu, 13 Apr 2006 20:05:23 -0400
X-Sieve: CMU Sieve 2.2
Received: from fort-point-station.mit.edu by po12.mit.edu (8.13.6/4.7) id k3E05Ep9021570; Thu, 13 Apr 2006 20:05:22 -0400 (EDT)
Received: from mail.netbsd.org (mail.netbsd.org [204.152.190.11])
	by fort-point-station.mit.edu (8.13.6/8.9.2) with ESMTP id k3E04XuZ011477
	for <mycroft at mit.edu>; Thu, 13 Apr 2006 20:04:33 -0400 (EDT)
Received: by mail.netbsd.org (Postfix)
	id 747AE63B13B; Fri, 14 Apr 2006 00:04:33 +0000 (UTC)
Delivered-To: mycroft at netbsd.org
Received: from multics.mit.edu (MULTICS.MIT.EDU [18.187.1.73])
	by mail.netbsd.org (Postfix) with ESMTP id 258C663B134
	for <mycroft at netbsd.org>; Fri, 14 Apr 2006 00:04:33 +0000 (UTC)
Received: (from mycroft at localhost) by multics.mit.edu (8.12.9)
	id k3E04SHB015708; Thu, 13 Apr 2006 20:04:28 -0400 (EDT)
Date: Thu, 13 Apr 2006 20:04:28 -0400
From: "Charles M. Hannum" <mycroft at MIT.EDU>
To: Joe Touch <touch at ISI.EDU>
Cc: "Charles M. Hannum" <mycroft at NetBSD.org>,
	Fahad Dogar <fahad.dogar at gmail.com>, Ted Faber <faber at ISI.EDU>,
	end2end-interest at postel.org
Subject: Re: [e2e] use of MAC addresses
Message-ID: <20060414000428.GN29472 at multics.mit.edu>
References: <cd4882200604121002g5745b3adgefc44cc16a582646 at mail.gmail.com> <443D3546.60506 at isi.edu> <cd4882200604121035l2ce35b98ob27074726c4dfb55 at mail.gmail.com> <443E76E0.1040600 at isi.edu> <cd4882200604131031n567650f2ue6928b6a3ba658ac at mail.gmail.com> <443E8CB8.8090601 at isi.edu> <20060413185956.GF29472 at multics.mit.edu> <443EC2A3.3000508 at isi.edu> <20060413220603.GM29472 at multics.mit.edu> <443ED483.1080805 at isi.edu>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <443ED483.1080805 at isi.edu>
User-Agent: Mutt/1.5.6i
X-Spam-Score: 3.548
X-Spam-Level: *** (3.548)
X-Spam-Flag: NO
X-Scanned-By: MIMEDefang 2.42

On Thu, Apr 13, 2006 at 03:45:23PM -0700, Joe Touch wrote:
> The "" in your response is important; many "shared media" these days
> aren't. That doesn't mean the MAC address isn't still useful, but it
> does mean it may not be necessary.

Sure.  As I pointed out before, lots of point-to-point protocols don't
have a notion of "link layer" addresses.  Take PPP, for example -- for
purposes of assigning addresses, it typically uses a combination of
{POP,user} as a unique identifier.  This works because the owner of the
POP can guarantee that the users are unique.

In a hypothetical setup where we have people roaming around between
different APs/POPs/whatever using possibly-conflicting identifiers,
this is all going to fall down.  Having a globally unique identifier
simplifies the problem tremendously.  What's the advantage of changing
it?  Some mythical notion that MAC addresses are "outdated" isn't going
to cut it.  Besides, we've already discussed several useful purposes
that the MAC address serves, so it's rather clearly *not* outdated.

----- End forwarded message -----


More information about the end2end-interest mailing list