From owner-freebsd-net@FreeBSD.ORG Sun Mar 11 06:50:13 2012 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id B61A0106564A for ; Sun, 11 Mar 2012 06:50:13 +0000 (UTC) (envelope-from bagadeh@gmail.com) Received: from mail-vx0-f182.google.com (mail-vx0-f182.google.com [209.85.220.182]) by mx1.freebsd.org (Postfix) with ESMTP id 691FB8FC18 for ; Sun, 11 Mar 2012 06:50:13 +0000 (UTC) Received: by vcmm1 with SMTP id m1so3700327vcm.13 for ; Sat, 10 Mar 2012 22:50:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=Rqc8Sv1RnextNeEmFlcmAq/mIQlugNL0aoXpDikwGEg=; b=Q7wXg8Tl3zvVUJvh5/TLOpi/o2uQAFXdnz4VkccgK/weRuZyChYsggdcppuXTw/u0i ygu1Ub3mVX31zhT0Rikpvrtngsw855isKDxvzUuS1+gpFVc8nrJc6bI0taJPWhjmuGOt tpjDQ7eyeLKHB1S3iuecd4WvPyD5CWbAtqX8XWBbLB7MnSW2CRdqyZ+lOrvJw5scBpiA FFPFUpU+yN14Ji8uNOlNonYYaEOxnduk/Uyfp81F9cfmT4cjKdBwgOdXiu2oZnDDrkZM nJk9Qfj1DRlQbUuj+pu/DtSlQJmADqgqts7rmS807yZYUJsKg8NYGIuvfPOoQiy7636f 4kcA== MIME-Version: 1.0 Received: by 10.52.90.178 with SMTP id bx18mr11308223vdb.123.1331448612807; Sat, 10 Mar 2012 22:50:12 -0800 (PST) Received: by 10.220.133.77 with HTTP; Sat, 10 Mar 2012 22:50:12 -0800 (PST) In-Reply-To: <20120306074655.GA71641@server.vk2pj.dyndns.org> References: <20120305084359.GA56606@server.vk2pj.dyndns.org> <20120305222811.GA64183@server.vk2pj.dyndns.org> <20120306074655.GA71641@server.vk2pj.dyndns.org> Date: Sun, 11 Mar 2012 10:20:12 +0330 Message-ID: From: h bagade To: Peter Jeremy Content-Type: text/plain; charset=ISO-8859-1 Cc: freebsd-net Subject: Re: problem with vlan interfaces tagging/untagging in a simulated switch box X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 11 Mar 2012 06:50:13 -0000 let me explain my problem with this type of topology when I want to simulate a switch like cisco eth1 -+ --- bridge1 --- vlan9 --+-- eth0 --- trunk0 | eth2 -+ --- bridge2 --- vlan8 --+ On 3/6/12, Peter Jeremy wrote: > On 2012-Mar-06 09:15:57 +0330, h bagade wrote: >>On 3/6/12, Peter Jeremy wrote: >>> The following example diagram shows 3 distinct packet flows: >>> - packets tagged 5 in trunk1 and 6 in trunk0 >>> - packets tagged 7 in trunk1 and 9 in trunk0 >>> - packets tagged 8 in trunk0 and 10 in trunk2 >>> >>> +-- vlan5 --- bridge1 --- vlan6 --+ >>> | | >>> trunk1 --- eth1 -+- vlan7 --- bridge2 --- vlan9 --+-- eth0 --- trunk0 >>> | >>> bridge3 --- vlan8 --+ >>> | >>> trunk2 -- eth2 --- vlan10 >>> >>I've described the function of Cisco switches in vlan >>tagging/untagging. > > Real switches typically have everything tagged internally, with the > native VLAN tags added/removed at the ingress/egress ports. This > simplifies the internal switch logic (at the expense of meaning that > tags have to be consistent across all trunks). > > FreeBSD works differently. Packets are _untagged_ internally and you > need a separate bridge(4) device for each broadcast domain (vlan). > >> In your topology, packets should be tagged when >>recieved on real interfaces to be send out to vlan interfaces. > > Packets are never tagged by real interfaces and always have tags > added/removed by vlan devices. > >> It >>would be fine when two trunks are communicating because on both side >>packets are tagged. But as I mentioned before, Cisco switches receive >>packets on an interface untagged and then sending packets tagged out >>of trunk port, based on which interface it receives, > > You can connect a physical interface (ethX) directly to a bridge device > to access untagged packets. Note that I'm not sure whether it is safe > to access the native VLAN in a trunk in this way. > > To continue the above example, > ifconfig bridge1 addm eth3 > would result in packets arriving on eth3 leaving tagged as vlan 5 in > trunk1, vlan 6 in trunk0 and vice versa. > > -- > Peter Jeremy >