Hot Standby Router Protocol (HSRP)

 R1 Configuration !!!!

interface FastEthernet0/0
 ip address 200.200.200.2 255.255.255.252

interface FastEthernet0/1
 ip address 192.168.1.100 255.255.255.0
 duplex auto
 speed auto
 standby version 2
 standby 1 ip 192.168.1.254
 standby 1 preempt

R2 Configuration !!!!

interface FastEthernet0/0
 ip address 200.200.200.6 255.255.255.252

interface FastEthernet0/1
 ip address 192.168.1.200 255.255.255.0
 duplex auto
 speed auto
 standby version 2
 standby 1 ip 192.168.1.254
 standby 1 preempt

LAN default gateway is 192.168.1.254.