Hello,

Simply I want to create a network on an existing bridge.
My XML:

<network>
  <name>nn1</name>
  <bridge name="br-nn1" />
</network>

when i want to start network I got "File exist" error.

error: Failed to start network nn1
error: Unable to create bridge br-nn1: File exist

I could define on older releases but now I can't.
Ubuntu 15.04 / libvirt version: 1.2.12

virsh version:
Compiled against library: libvirt 1.2.12
Using library: libvirt 1.2.12
Using API: QEMU 1.2.12
Running hypervisor: QEMU 2.2.0

Is there any way to activate network?

Regards.