How to create a Linux bridge:
[root@epi templates]# brctl show
bridge name bridge id STP enabled interfaces
virbr0 8000.5254007ce67f yes virbr0-nic

[root@epi templates]# brctl addbr br1
[root@epi templates]# brctl addif br1 eth1
[root@epi templates]# brctl show
bridge name bridge id STP enabled interfaces
br1 8000.3cd92bf6f11c no eth1
virbr0 8000.5254007ce67f yes virbr0-nic
[root@epi templates]#