From owner-freebsd-arch@FreeBSD.ORG Fri Sep 30 09:56:52 2005 Return-Path: X-Original-To: freebsd-arch@freebsd.org Delivered-To: freebsd-arch@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9824016A41F for ; Fri, 30 Sep 2005 09:56:52 +0000 (GMT) (envelope-from PeterJeremy@optushome.com.au) Received: from mail25.syd.optusnet.com.au (mail25.syd.optusnet.com.au [211.29.133.166]) by mx1.FreeBSD.org (Postfix) with ESMTP id E802843D49 for ; Fri, 30 Sep 2005 09:56:51 +0000 (GMT) (envelope-from PeterJeremy@optushome.com.au) Received: from cirb503493.alcatel.com.au (c220-239-19-236.belrs4.nsw.optusnet.com.au [220.239.19.236]) by mail25.syd.optusnet.com.au (8.12.11/8.12.11) with ESMTP id j8U9un7w015243 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO) for ; Fri, 30 Sep 2005 19:56:50 +1000 Received: from cirb503493.alcatel.com.au (localhost.alcatel.com.au [127.0.0.1]) by cirb503493.alcatel.com.au (8.12.10/8.12.10) with ESMTP id j8U9unSR075748 for ; Fri, 30 Sep 2005 19:56:49 +1000 (EST) (envelope-from pjeremy@cirb503493.alcatel.com.au) Received: (from pjeremy@localhost) by cirb503493.alcatel.com.au (8.12.10/8.12.9/Submit) id j8U9unwE075747 for freebsd-arch@freebsd.org; Fri, 30 Sep 2005 19:56:49 +1000 (EST) (envelope-from pjeremy) Date: Fri, 30 Sep 2005 19:56:49 +1000 From: Peter Jeremy To: freebsd-arch@freebsd.org Message-ID: <20050930095649.GK72352@cirb503493.alcatel.com.au> References: <200509241525.16173.max@love2party.net> <20050924192237.GP40237@cirb503493.alcatel.com.au> <20050928102153.GA86457@comp.chem.msu.su> <20050928032933.G16027@xorpc.icir.org> <20050928184731.GA72352@cirb503493.alcatel.com.au> <20050928231409.GB38338@squash.dsto.defence.gov.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050928231409.GB38338@squash.dsto.defence.gov.au> User-Agent: Mutt/1.4.2.1i Subject: Re: Bridges X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 30 Sep 2005 09:56:52 -0000 On Thu, 2005-Sep-29 08:44:09 +0930, Wilkinson, Alex wrote: >What is the difference between a "per-host MAC address" and a "per-NIC >MAC address" ? All NICs have a unique MAC address. This address can be over-ridden by the host if it needs to have the same MAC address appear on multiple interfaces. Of the two cases I mentioned: DECnet changes all MAC addresses to one beginning AA0055 where the low bits are the host's DECnet address. This removes the need for IP's ARP since the source host can determine the destination host's MAC address without needing to ask the network. Some versions of Solaris with some NICs (definitely Solaris 8 with Cassini NICs) associate a MAC address with the host, rather than the NIC. I'm less certain of the rationale for this. -- Peter Jeremy