HSRP - Hot Standby Redundancy protocol

NB! Balancing per subnet

R1#sh run
!
interface FastEthernet0/0
 ip address 192.168.0.10 255.255.255.0
 duplex auto
 speed auto
 standby 1 ip 192.168.0.1
!
interface Serial1/0
 ip address 10.0.0.2 255.255.255.252
 serial restart-delay 0
!
ip route 0.0.0.0 0.0.0.0 Serial1/0
!

R2#sh run
!
interface FastEthernet0/0
 ip address 192.168.0.20 255.255.255.0
 duplex auto
 speed auto
 standby 1 ip 192.168.0.1
!
interface Serial1/0
 ip address 10.0.0.6 255.255.255.252
 serial restart-delay 0
!
ip route 0.0.0.0 0.0.0.0 Serial1/0
!

R3#sh run
!
interface Loopback2
 ip address 10.0.0.9 255.255.255.255
!
interface Serial1/0
 ip address 10.0.0.1 255.255.255.252
 serial restart-delay 0
!
interface Serial1/1
 ip address 10.0.0.5 255.255.255.252
 serial restart-delay 0
!
ip route 192.168.0.0 255.255.255.0 Serial1/0
ip route 192.168.0.0 255.255.255.0 Serial1/1
!

R1#sh standby br
Interface   Grp Prio P State    Active          Standby         Virtual IP    
Fa0/0       1   100    Standby  192.168.0.20    local           192.168.0.1   

R2#sh stand br
Interface   Grp Prio P State    Active          Standby         Virtual IP    
Fa0/0       1   100    Active   local           192.168.0.10    192.168.0.1