ifconfig
$this->bbcode_second_pass_code('', '
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc mq master br0 state UP group default qlen 1000
    link/ether 00:25:31:04:97:78 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::225:31ff:fe04:9778/64 scope link 
       valid_lft forever preferred_lft forever
3: eth1: <NO-CARRIER,BROADCAST,MULTICAST,PROMISC,UP> mtu 1500 qdisc pfifo_fast master br0 state DOWN group default qlen 1000
    link/ether 8c:ae:4c:ff:6b:42 brd ff:ff:ff:ff:ff:ff
4: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
    link/ether 00:25:31:04:97:78 brd ff:ff:ff:ff:ff:ff
    inet 192.168.51.7/24 brd 192.168.51.255 scope global br0
       valid_lft forever preferred_lft forever
    inet6 fe80::225:31ff:fe04:9778/64 scope link 
       valid_lft forever preferred_lft forever
')
kernel
$this->bbcode_second_pass_code('', 'Linux version 3.14.4-1-ARCH (nobody@root-armv5-copy) (gcc version 4.8.2 20131219 (prerelease) (GCC) ) #1 PREEMPT Thu May 15 19:38:21 MDT 2014
')
/etc/netctl/bridge
$this->bbcode_second_pass_code('', '
[root@pogopig proc]# cd /etc/netctl/
[root@pogopig netctl]# cat bridge
Description="Example Bridge connection"
Interface=br0
Connection=bridge
BindsToInterfaces=(eth0 eth1 )
IP=dhcp
## Ignore (R)STP and immediately activate the bridge
#SkipForwardingDelay=yes
')
lsmod shows $this->bbcode_second_pass_code('', '
Module                  Size  Used by
bridge                 92478  0 
stp                     1363  1 bridge
llc                     3232  2 stp,bridge
snd_usb_audio         100109  0 
snd_usbmidi_lib        17534  1 snd_usb_audio
snd_hwdep               4942  1 snd_usb_audio
snd_rawmidi            16868  1 snd_usbmidi_lib
uvcvideo               67101  1 
videobuf2_vmalloc       2649  1 uvcvideo
videobuf2_memops        1360  1 videobuf2_vmalloc
videobuf2_core         26426  1 uvcvideo
snd_seq_device          4958  1 snd_rawmidi
snd_pcm                69866  1 snd_usb_audio
asix                   18171  0 
videodev              110376  3 uvcvideo,videobuf2_core
snd_timer              17727  1 snd_pcm
snd                    42695  7 snd_usb_audio,snd_hwdep,snd_timer,snd_pcm,snd_rawmidi,snd_usbmidi_lib,snd_seq_device
soundcore                728  1 snd
media                  10515  2 uvcvideo,videodev
usbnet                 18905  1 asix
mv_cesa                11034  0 
ipv6                  300997  23 bridge
autofs4                23037  2 
')
The USBNIC is a  Plugable USB2-E1000
motion is using about 24% CPU
How muh more do you need ???
As you can see one of the interfaces is down at the moment 

HTH
thanks