[CentOS-virt] KVM, VLAN and Bridges and bonding

Hi all,

I use CentOS5.x + Xen in production for virtualization. I use it with bridged vlan networks and bonding (active-backup) like that:

eth0  eth1
 |     |
 -------
    |
  bond0-------bond0.10---------bond0.12 ...
    |            |                |
    |         vlanbr10         vlanbr12
  dom0           |                |
           -------------     -------------- 
           |     |     |     |     |      |  ...
         domU1 domU2 domU3 domU4 domU5  domU6

For future hypervisors, i want to implement the same things with CentOS6.x + KVM. In test env i've setup CentOS6.2 + KVM (with last updates) with the same network config, but guest lose network connection very often, and i don't know why.

Network config:

/etc/sysconfig/network-scripts/ifcfg-bond0.6:
DEVICE=bond0.6
BRIDGE=vlanbr6
ONBOOT=yes
BOOTPROTO=none
VLAN=yes
TYPE=Ethernet

/etc/sysconfig/network-scripts/ifcfg-vlanbr6:
DEVICE=vlanbr6
TYPE=Bridge
ONBOOT=yes
BOOTPROTO=none
DELAY=0

I've installed guest like that (with a lot of retry because of network loss during installation)

virt-install --name=guest02-c6 --disk path=/var/lib/libvirt/images/guest02-c6.img,size=10,sparse=false --graphics=spice,keymap=fr --vcpus=2 --ram=2048 --location=http://spacewalk.example.com/pub/dist/centos/6/x86_64/ --extra-args="ks=http://spacewalk.example.com/pub/ks/el6/guest02.el6.cfg ip=192.168.2.12 netmask=255.255.255.224 gateway=192.168.2.10 dns=192.168.2.10" --os-type=linux --os-variant=rhel6 --network=bridge:vlanbr6,model=virtio

Someone have setup similar environment ?

Regards.

Baptiste.