Configure HSRP on a router with Backup Interfce

[hemantpatel]

We have 2 cisco 1921routers (R1 and R1) both have 2 interfaces Gi0/0 and Gi0/1. We have 2 cisco 2960G Ethernet switches S1 and S2 are connected to each other. Each router is connected to both Ethernet switches. On each router has Gi0/0 as the primary interface and Gi0/1 as backup interface. I am able to configure hsrp on primary interface but it does not allow me to configure same standby ip on backup interface.

Our intent is to provide fault tolerance on both router as well as Ethernet switch level.

R1-Gi0/0 -->S1  and R1-Gi0/1 -->S2

R2-Gi0/0 -->S1  and R2-Gi0/1 -->S2

interface GigabitEthernet0/0
    backup interface GigabitEthernet0/1
    ip address 192.168.101.2 255.255.255.0
    standby 1 ip 192.168.101.1
    standby 1 priority 101
    standby 1 preempt
    duplex auto
    speed auto
 

interface GigabitEthernet0/1
 ip address 192.168.101.2 255.255.255.0
 standby 1 priority 102
 standby 1 preempt
 duplex auto
 speed auto
 

[devils_advocate]

What you are trying to achieve is not possible in the way you are doing it.

You will not be able to create a second IP address in an existing subnet on the same routed device.

Routers make forwarding decisions based on the Destination IP address of incoming packets. The routing table on each of your routers will list a connected route for the whole 192.168.101.0 /24 subnet. That connected route will list the routers interface to which the subnet is connected to.

The router will not allow two connected routes to the same subnet, otherwise it will not know where to forward packets to.

There may be a way to achieve your end goal but you cannot create a second ip address in the 192.168.101.0 /24 subnet on the same router. 

Thanks