Hi there, We experienced network problems (namely net packet storm), when using multiple NICs and the same VLAN ID-s for different KVM guests. It turned out that we could workaround the problem by simply assigning different VLAN ID-s to the different NICs. (Btw our case looked similar to the one that was posted and discussed on the KVM mailing list. Also the solution was picked from that discussion. See: http://www.mail-archive.com/kvm@xxxxxxxxxxxxxxx/msg24203.html, for details) We could resolve the problem at the KVM layer, however we have to do it at the libvirt layer, too. Running thru qemu_conf.c, and executing some unit tests with different type of interfaces (eg. ethernet, bridge, network), it turned out, that libvirt reassigns the same vlan ids to the guests starting from 0... So far the only solution we could figure out is to use a wrapper script around the KVM binary that replaces VLAN ID-s with unique ones. This one was picked up from a recent discussion on the upcoming debug API (http://www.mail-archive.com/libvir-list@xxxxxxxxxx/msg23140.html). However the method was marked fragile in the list, due the evolving nature of the libvirt API. My questions: - Did anyone experience similar problems, and come up with a clean solution? Specially is there any better way to provide unique VLAN ID-s thru libvirt then the above one? As far as I see the upcoming -netdev option (introduced in QEMU 0.12) will solve the question. However this was removed from libvirt, since the corresponding qemu monitor command is not yet developed: - Do you have a target release for the -netdev option, or is it unknown (eg. dependent on the yet unknown KVM/QEMU development schedule)? Cheers, Gyula Ps.: our env: Debian GNU/Linux, libvirt, kvm, ebtables -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list