Step 1 :

Create the file /etc/sysconfig/network-scripts/ifcfg-bond0 and specify the ip address,netmask & gateway

# vi /etc/sysconfig/network-scripts/ifcfg-bond0
 DEVICE=bond0
 IPADDR=192.168.100.10
 NETMASK=255.255.255.0
 GATEWAY=192.168.100.1
 TYPE=Bond
 ONBOOT=yes
 NM_CONTROLLED=no
 BOOTPROTO=static

Step:2 

Edit the files of eth0 & eth1 and make sure you enter the master and slave entry, as shown below
 # vi /etc/sysconfig/network-scripts/ifcfg-eth0
 DEVICE=eth0
 HWADDR=90:2b:34:7b:df:a4
 TYPE=Ethernet
 ONBOOT=yes
 NM_CONTROLLED=no
 MASTER=bond0
 SLAVE=yes

# vi /etc/sysconfig/network-scripts/ifcfg-eth1
 DEVICE=eth1
 TYPE=Ethernet
 HWADDR=e2:5b:f0:60:ba:d8
 ONBOOT=yes
 NM_CONTROLLED=no
 MASTER=bond0
 SLAVE=yes

 Step:3 

Create the Bond file(bonding.conf)
 # vi /etc/modprobe.d/bonding.conf ( for old versions use modprobe.conf )
 alias bond0 bonding
 options bond0 mode=1 miimon=100  <--- This can be defined in  ifcfg-bond0  the line will be BONDING_OPTS="mode=1 miimon=100"
change above line to
options bond0 mode=1 miimon=100 fail_over_mac=1  if you are configuring bonding under vmware workstation.



Step:4 

service network restart

Important Things to know

A ) Different Modes used in bonding
 balance-rr or 0 -- round-robin mode for fault tolerance and load balancing.
 active-backup or 1 -- Sets active-backup mode for fault tolerance.
 balance-xor or 2 -- Sets an XOR (exclusive-or) mode for fault tolerance and load balancing.
 broadcast or 3 -- Sets a broadcast mode for fault tolerance. All transmissions are sent on all slave interfaces.
 802.3ad or 4 -- Sets an IEEE 802.3ad dynamic link aggregation mode. Creates aggregation groups that share the same speed & duplex settings.
 balance-tlb or 5 -- Sets a Transmit Load Balancing (TLB) mode for fault tolerance & load balancing.
 balance-alb or 6 -- Sets an Active Load Balancing (ALB) mode for fault tolerance & load balancing.




B ) Commands

To check the bonding status

watch -n .1 cat /proc/net/bonding/bond0   

or

cat /proc/net/bonding/bond0


To Change active interface in bondig 1 ) remove active interface from bonding by command  echo -eth0 > /sys/class/net/bond0/bonding/slaves this will make the other slave active then add it again into the bonding. by running command echo +eth0 > /sys/class/net/bond0/bonding/slaves or use inenslave to change the active slave in bond To make eth0 active use below command ifenslave -c bond0 eth0 eth1