Hi, We would like to use VLAN tagged packets to be sent/received by the guest VMs running on xen hypervisor. Does xen bridging support vlan tagged packets arriving on the physical nic from outside of the xen host to be passed through with the vlan tag to the vif of the guest with the guest VM receiving the tagged packet ? We have a xenbr configured with two interfaces - eth3 (physical nic of the host), vif23.2 (vif of guest VM running in domain 23). Sniffing the packet just outside the physical NIC does show that it has the vlan tag, but tcpdump on eth3 shows that the vlan tag has been stripped. Any ideas pls ? Looks like open vswitch supports the above mode of operation. -kvc _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Vijay Chander wrote:>We would like to use VLAN tagged packets to be sent/received by the >guest VMs running on xen hypervisor. > >Does xen bridging support vlan tagged packets arriving on the >physical nic from outside of the xen host to be passed through with >the vlan tag to the vif of the guest with the guest VM receiving the >tagged packet ?This comes up quite recently, just this week in fact if you look in the archives. Simple answer: The "standard" setup using kernel bridges does not support tagged packets. You can run a NIC with tagged packets, but you connect each VLAN to a separate bridge, and provide multiple virtual NICs to each guest. Some people are now reporting success using Open vSwitch? http://openvswitch.org/ - in particular see the message from yesterday by Michael A. Collins in the thread Some VLAN ideas for discussion. This does support handling tagged packets in the virtual switch and guest virtual NICs. -- Simon Hobson Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed author Gladys Hobson. Novels - poetry - short stories - ideal as Christmas stocking fillers. Some available as e-books.
On 2012-01-11 07:16, Vijay Chander wrote:> Does xen bridgingsupport vlan tagged packets> arriving on the physical nic from outsideof the xen host to be passed through with the> vlan tag to the vif ofthe guest with the guest VM receiving the tagged packet ?> Xen doesnot have any special bridging code, just scripts (releases <=4.1.x) which manipulate the features found in the standard kernel. If you can do it without Xen you should be able to do it with Xen, in this case yes.> We have a xenbr configured with two interfaces - eth3 (physicalnic of the host),> vif23.2 (vif of guest VM running in domain 23).Sniffing the packet just outside the> physical NIC does show that ithas the vlan tag, but tcpdump on eth3 shows that> the vlan tag hasbeen stripped. Any ideas pls ?> Are you tagging the traffic in thedom0 or the domU? The recommended setup is to tag packets in the dom0 with a network configuration like> dom0 domU > Physical eth3 - [ VLANeth3.xxx - ( xenbr0 ] - vif23.x )> Where xenbr0 has an IP has an IP onthe VLAN if you need to address the dom0 as well, otherwise a null configuration if just the domU.> Here the domU has no knowledge thatit is part of a VLAN but the packets are tagged when they pass through the dom0 VLAN interface.> James_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users