From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Chmielewski Subject: VLANs with Xen - work with 1 Gbit, doesn't with 100 Mbit cards? Date: Fri, 02 Feb 2007 19:35:11 +0100 Message-ID: <45C3845F.2060802@wpkg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-2; format=flowed Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org I have a strange problem with VLANs with Xen 3.0.4. I signalled it on Xen-users list, but found no definitive solution to it. I configure VLANs so that they are available in dom0; domUs don't know that they use VLANs. I use a stock "network-bridge" comming from Xen for setting up networking: #!/bin/bash dir=$(dirname "$0") "$dir/network-bridge" "$@" vifnum=0 netdev=eth0 bridge=xenbr0 "$dir/network-bridge" "$@" vifnum=1 netdev=eth0.100 bridge=xenbr100 "$dir/network-bridge" "$@" vifnum=2 netdev=eth0.200 bridge=xenbr200 If the server has a 1 Gbit network card (e1000, tg3 module), VLANs work flawlessly. If, however, I replace the card, and use a 100 Mbit one (Intel/e100 or Realtek/8139too module), and don't change the scripts, VLANs are not working. Why is it so? What is so fundamental in Xen networking that VLANs behaviour change so much whether one uses a 1 Gbit, or 100 Mbit network cards? There is one difference between 1 Gbit and 100 Mbit cards - 100 Mbit cards won't allow to set the MTU bigger than 1500: # ifconfig eth1 mtu 1501 SIOCSIFMTU: Invalid argument But I'm not sure if it has anything with the described VLAN problem. On the other hand, if I configure VLANs in domU, it works fine then (but it's a bad approach for me, and prefer to have VLANs in dom0 only). -- Tomasz Chmielewski http://wpkg.org