From owner-freebsd-arch@FreeBSD.ORG Wed Sep 28 23:17:09 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 659C116A41F for ; Wed, 28 Sep 2005 23:17:09 +0000 (GMT) (envelope-from wilkinsa@squash.dsto.defence.gov.au) Received: from digger1.defence.gov.au (digger1.defence.gov.au [203.5.217.4]) by mx1.FreeBSD.org (Postfix) with ESMTP id 18C1443D5F for ; Wed, 28 Sep 2005 23:16:56 +0000 (GMT) (envelope-from wilkinsa@squash.dsto.defence.gov.au) Received: from ednmsw501.dsto.defence.gov.au (ednmsw501.dsto.defence.gov.au [131.185.2.150]) by digger1.defence.gov.au with ESMTP id j8SNEvRl003760 for ; Thu, 29 Sep 2005 08:44:57 +0930 (CST) Received: from muttley.dsto.defence.gov.au (unverified) by ednmsw501.dsto.defence.gov.au (Content Technologies SMTPRS 4.3.17) with ESMTP id ; Thu, 29 Sep 2005 08:46:47 +0930 Received: from ednex501.dsto.defence.gov.au (ednex501.dsto.defence.gov.au [131.185.2.81]) by muttley.dsto.defence.gov.au (8.11.3/8.11.3) with ESMTP id j8SNDm018882; Thu, 29 Sep 2005 08:43:48 +0930 (CST) Received: from squash.dsto.defence.gov.au ([131.185.40.212]) by ednex501.dsto.defence.gov.au with SMTP (Microsoft Exchange Internet Mail Service Version 5.5.2653.13) id SJZBS2AB; Thu, 29 Sep 2005 08:43:46 +0930 Received: from squash.dsto.defence.gov.au (localhost [127.0.0.1]) by squash.dsto.defence.gov.au (8.13.3/8.13.3) with ESMTP id j8SNECYP038403; Thu, 29 Sep 2005 08:44:12 +0930 (CST) (envelope-from wilkinsa@squash.dsto.defence.gov.au) Received: (from wilkinsa@localhost) by squash.dsto.defence.gov.au (8.13.3/8.13.3/Submit) id j8SNE9Rw038402; Thu, 29 Sep 2005 08:44:09 +0930 (CST) (envelope-from wilkinsa) Date: Thu, 29 Sep 2005 08:44:09 +0930 From: "Wilkinson, Alex" To: Peter Jeremy Message-ID: <20050928231409.GB38338@squash.dsto.defence.gov.au> Mail-Followup-To: Peter Jeremy , Luigi Rizzo , Yar Tikhiy , freebsd-arch@freebsd.org, Max Laier 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> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20050928184731.GA72352@cirb503493.alcatel.com.au> User-Agent: Mutt/1.5.10i Cc: freebsd-arch@freebsd.org, Max Laier , Yar Tikhiy 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: Wed, 28 Sep 2005 23:17:09 -0000 0n Thu, Sep 29, 2005 at 04:47:32AM +1000, Peter Jeremy wrote: >On Wed, 2005-Sep-28 03:29:33 -0700, Luigi Rizzo wrote: >>On Wed, Sep 28, 2005 at 02:21:53PM +0400, Yar Tikhiy wrote: >>> On Sun, Sep 25, 2005 at 05:22:38AM +1000, Peter Jeremy wrote: >>> > >>> > Since I've recently needed it, neither bridge.c nor if_bridge.c allow >>> > you to bridge VLAN trunks (you can bridge individual VLANs but that >>> > becomes unwieldly when you have dozens of VLANs). I have code to do >>> > this in bridge.c. >>> >>> Couldn't you bridge across the parent, or trunk, physical interfaces >>> carrying tagged VLAN traffic then? (Of course, hardware support for >>> VLAN should be turned off on them in that case.) > >That's actually what I was trying to do. > >>yes in fact i was wondering what's wrong with that because >>we have been using bridge.c like this for ages now... > >The problem is that the current bridge code only considers the MAC >address for forwarding. When VLANs are in use, this is incorrect as >both the MAC address and VLAN tag must be considered. The difference >is crucial when you have the same MAC address appearing in multiple >VLANs. This can occur when using DECnet Phase IV or Solaris with >Cassini NICs - both of which have a per-host MAC address rather than a >per-NIC MAC address. > >As an example, consider a system with a host-based MAC address that >has two NICs. One NIC attaches to VLAN 123 on switch a, the other >attaches to VLAN 124 on switch b [this is the situation we have in our >test lab]. If I then attempt to join trunks from both switches using >bridge(4), it sees the same MAC address on both bridged interfaces and >shuts down. In reality, this situation is safe because the MAC >addresses are in different VLANs. Peter, What is the difference between a "per-host MAC address" and a "per-NIC MAC address" ? - aW