The configuration for bonding with RHEL5 involves four files (for a 2 NIC bond):

1)  Bonding module:  /etc/modprobe.conf:

     The modprobe.conf module should have the following lines added:
     #bond<n>   in the case of a single bonding, bond0
      alias bond0 bonding
     #parameter definitions - for failover,  mode=1 and we set the trigger time to 100 milliseconds, miimon=100
     options bond0 mode=1 miimon=100

2) Bonding NIC.  The bonding NIC (bond<n>, or in our case, bond0).  The bond0 NIC definition is used as the master and contains the network parameters usually associated with
     a NIC that interfaces with the external network, i.e., IPADDR, NETMASK, GATEWAY etc. and the syntax is the same.  
     The bonding NIC resides in the same directory as the standard NICs:  /etc/sysconfig/network-scripts.  (parameters below left blank after '=' but would normally be filled in)
   
      DEVICE=bond0
      # If DHCP is not used
      BOOTPROTO=none
     ONBOOT=yes
     IPADDR=
     NETMASK=
     GATEWAY=
     NETWORK=

3) Physical NICs that will be bonded to gether into bond0:  /etc/sysconfig/network-scripts  in two files:  ifcfg-eth0 and ifcfg-eth1
   #one file each for eth0 and eth1
    DEVICE=eth0
    BOOTPROTO=none
    ONBOOT=yes
    MASTER=bond0
    SLAVE=yes
    USERCTL=no