Xen Ha And Private Bridges - Novell SUSE LINUX ENTERPRISE DESKTOP 11 SP1 - 8-18-2010 VIRTUALIZATION WITH ZEN Manual

During the setup, each of the required block devices should use its own DRBD device.
The setup of such a system is quite a complex task. An example that is actually used
http://en.opensuse.org/Xen3
in a productive environment is described in
_and_Distributed_Local_Storage.

11.3 Xen HA and Private Bridges

When using several guest systems that need to communicate between each other, it is
possible to do this over the regular interface. However, for security reasons it may be
advisable to create a bridge that is only connected to guest systems.
In a HA environment that also should support live migrations, such a private bridge
must be connected to the other Xen hosts. This is possible by using dedicated physical
Ethernet devices, and also using a dedicated network.
A different implementation method is using VLAN interfaces. In that case, all the
traffic goes over the regular Ethernet interface. However, the VLAN interface does not
get the regular traffic, because only the VLAN packets that are tagged for the correct
VLAN are forwarded.
For more information about the setup of a VLAN interface see Section 6.5.4, "Using
VLAN Interfaces" (page 57).
Xen as High Availability Virtualization Host 97