This  KB describes how to create a  bonding interface which mode is enabled  "fault-tolerance".

Step 1: Determine your  slave network and configure them

For Slave 1:

# cat /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
TYPE=Ethernet
ONBOOT=yes
NM_CONTROLLED=no
BOOTPROTO=none
USERCTL=no
SLAVE=yes
MASTER=bond0

For Slave 2:

# cat /etc/sysconfig/network-scripts/ifcfg-eth1
DEVICE=eth1
TYPE=Ethernet
ONBOOT=yes
NM_CONTROLLED=no
BOOTPROTO=none
USERCTL=no
SLAVE=yes
MASTER=bond0

Step 2:Configure  bonding  interface

# cat /etc/sysconfig/network-scripts/ifcfg-bond0
DEVICE=bond0
ONBOOT=yes
NM_CONTROLLED=no
BOOTPROTO=none
USERCTL=no
IPADDR=192.168.50.60
NETMASK=255.255.255.0
GATEWAY=192.168.50.10
BONDING_OPTS="mode=1 miimon=100"

Step 3:Define  configuration  type for bonding

#cat /etc/modprobe.d/bonding.conf
alias bond0 bonding
options bond0 mode=active-backup miimon=100 downdelay=200 updelay=200

Step 4:Restart  Network

#service network restart