Centos 6 bridge network

Directory /etc/sysconfig/network-scripts/

Note:
Instead of turning off NetworkManager , add "NM_CONTROLLED=no " to the ifcfg-* .

Edit or create /etc/sysconfig/network-scripts/ifcfg-eth0:
DEVICE=eth0
TYPE=Ethernet
BOOTPROTO=none
# change the hardware address to match the hardware address your NIC uses
HWADDR=00:16:76:D6:C9:45
ONBOOT=yes
BRIDGE=br0
NM_CONTROLLED=no

Edit or create /etc/sysconfig/network-scripts/ifcfg-br0 dhcp:
DEVICE=br0
TYPE=Bridge
BOOTPROTO=dhcp
ONBOOT=yes
NM_CONTROLLED=no
DELAY=0

Edit or create /etc/sysconfig/network-scripts/ifcfg-br0 static
DEVICE=br0
TYPE=Bridge
IPADDR=192.168.1.1
NETMASK=255.255.255.0
ONBOOT=yes
BOOTPROTO=none
NM_CONTROLLED=no
DELAY=0

# service network restart

Iptables
# iptables -I FORWARD -m physdev --physdev-is-bridged -j ACCEPT
# service iptables save
# service iptables restart

Edit and append /etc/sysctl.conf:
net.bridge.bridge-nf-call-ip6tables = 0
net.bridge.bridge-nf-call-iptables = 0
net.bridge.bridge-nf-call-arptables = 0

Reload kernel parameter and libvirt service
# sysctl -p /etc/sysctl.conf
# service libvirtd reload

# brctl show

-----------------------------
2 nic bond
-----------------------------
Edit or create /etc/sysconfig/network-scripts/ifcfg-eth0:
DEVICE=eth0
TYPE=Ethernet
BOOTPROTO=none
# change the hardware address to match the hardware address your NIC uses
HWADDR=00:16:76:D6:C9:45
ONBOOT=yes
BRIDGE=br0
NM_CONTROLLED=no
USERCTL=no
SLAVE=yes
MASTER=bond0

Edit or create /etc/sysconfig/network-scripts/ifcfg-eth1:
DEVICE=eth1
TYPE=Ethernet
BOOTPROTO=none
# change the hardware address to match the hardware address your NIC uses
HWADDR=00:16:76:D6:C9:45
ONBOOT=yes
BRIDGE=br0
NM_CONTROLLED=no
USERCTL=no
SLAVE=yes
MASTER=bond0

Edit or create /etc/sysconfig/network-scripts/ifcfg-bond0:
DEVICE=bond0
ONBOOT=yes
BONDING_OPTS='mode=1 miimon=100'
BRIDGE=br0
NM_CONTROLLED=no
BOOTPROTO=none

Edit or create /etc/sysconfig/network-scripts/ifcfg-br0:
DEVICE=br0
ONBOOT=yes
TYPE=Bridge
IPADDR=192.168.1.1
NETMASK=255.255.255.0
NM_CONTROLLED=no

Available bond mode:
balance-rr or 0
active-backup or 1
balance-xor or 2
broadcast or 3
802.3ad or 4
balance-tlb or 5
balance-alb or 6

https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Deployment_Guide/s2-networkscripts-interfaces_network-bridge.html
http://www.linux-kvm.org/page/HOWTO_BONDING#Problem_with_Bridge_.2B_Bonding