Gateway Load Balancing Protocol (GLBP) protects data traffic from a failed router or circuit, like Hot Standby Router Protocol (HSRP) and Virtual Router Redundancy Protocol (VRRP), while allowing packet load sharing between a group of redundant routers.

Primary Router Config :

interface GigabitEthernet0/0
 description Comms-Primary-Router
 ip address 10.10.10.1 255.255.255.0
 ip nat inside
 ip inspect myfw in
 ip virtual-reassembly
 duplex auto
 speed auto
 glbp 1 ip 10.10.10.254
 glbp 1 timers msec 500 2
 glbp 1 priority 150
 glbp 1 preempt delay minimum 5
 glbp 1 weighting 110 lower 90
 glbp 1 authentication md5 key-string 0 group1
 glbp 1 name BSSGROUP
 glbp 1 weighting track 1 decrement 30
 glbp 1 forwarder preempt delay minimum 5
!
!
track 1 interface GigabitEthernet0/1 line-protocol
!
interface GigabitEthernet0/1
description WAN_Interface
 ip address 2.2.2.2 255.255.255.0
  ip nat outside
 ip virtual-reassembly
 duplex auto
 speed auto

Secondary Router Config :

interface GigabitEthernet0/0
 description Comms-Secondary-Router
 ip address 10.10.10.2 255.255.255.0
 ip nat inside
 ip virtual-reassembly
 duplex auto
 speed auto
 glbp 1 ip 10.10.10.254
 glbp 1 timers msec 500 2
 glbp 1 priority 150
 glbp 1 preempt delay minimum 5
 glbp 1 weighting 110 lower 90
 glbp 1 authentication md5 key-string 0 group1
 glbp 1 name BSSGROUP
 glbp 1 weighting track 1 decrement 30
 glbp 1 forwarder preempt delay minimum 5
!
!
track 1 interface GigabitEthernet0/1 line-protocol
!
interface GigabitEthernet0/1
description WAN_Interface
 ip address 1.1.1.1 255.255.255.0
 ip nat outside
 ip virtual-reassembly
 duplex auto
 speed auto