Create bond interface.

vi /etc/sysconfig/network-scripts/ifcfg-bond0
DEVICE=bond0
BOOTPROTO=none
ONBOOT=yes
USERCTL=no
BONDING_OPTS="mode=4 miimon=100"

Load kernel bond0 interface.

vi /etc/modprobe.d/bonding.conf
alias netdev-bond0 bonding

Add interfaces to bond.

vi /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
MASTER=bond0
SLAVE=yes
USERCTL=no
ONBOOT=yes
BOOTPROTO=none

vi /etc/sysconfig/network-scripts/ifcfg-eth1
DEVICE=eth1
MASTER=bond0
SLAVE=yes
USERCTL=no
ONBOOT=yes
BOOTPROTO=none

vi /etc/sysconfig/network-scripts/ifcfg-eth3
DEVICE=eth3
MASTER=bond0
SLAVE=yes
USERCTL=no
ONBOOT=yes
BOOTPROTO=none

Load bonding module.

modprobe bonding

Show bonding stats.

cat /proc/net/bonding/bond0

Create VLAN50 device and bridge for KVM guests.

vi /etc/sysconfig/network-scripts/ifcfg-br50
DEVICE=br50
ONBOOT=yes
SLAVE=bond0.50
TYPE=Bridge
VLAN=yes
NM_CONTROLLED=no

vi /etc/sysconfig/network-scripts/ifcfg-bond0.50
DEVICE=bond0.50
VLAN=yes
ONBOOT=yes
USERCTL=no
NM_CONTROLLED=no
BRIDGE=br50