Failover solution

[arun-r]

I have two router with hsrp configured. One router has priority of 200 and other has priority of 190.The secondary router wan is down by default, so we have a track configured that brings the priority to 190-50=140. Now,I have a situation where the primary wan went down,and the priority went down to 150, but the primary router is still active. On the secondary router, cellular is up, but the traffic is not going via cellular since the primary is still active. What would be the solution when the primary goes down, the traffic should go via secondary cellular. 

[Georg Pauwen]

您好，您需要的是 IP SLA。发布两个路由器的配置，这样我们就可以添加这个......

[MHM Cisco World]

can you draw topology 
thanks 

MHM

[arun-r]

PFA, the topo

[MHM Cisco World]

you need to add in primary/secondary preempt 
this make it send HSRP info all routers that is now can be active when primary router priority decrease to 150

MHM

[Giuseppe Larosa]

Hello @arun-r ,

on secondary router you should track both the WAN interface and the cellular interface but you should not reduce the HSRP priority by 40 when only one of them is down but by 20 so that HSRP priority will be 170 on secondary router when its WAN is down.

As noted you need preemption  enabled on both devices.

You may want to have the cell to dial out when the WAN is down dialer-watch or backup config can be used for this.

Hope to help

Giuseppe

[paul driver]

Hello

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@arun-r wrote:
Now,I have a situation where the primary wan went down,and the priority went down to 150, but the primary router is still active. On the secondary router, cellular is up, but the traffic is not going via cellular since the primary is still active. 

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Sound like HSRP is working but you don't have any care conditional default routing regards on the primary/secondary wan interfaces which can be accomplished with IPSLA/object tracking.

Can you also confirm if you have NAT enabled on the HSRP interfaces?

[mohamedlamine]

you can make additional configurations in HSRP. Here's what you can do:

1. Adjust HSRP Priority on Secondary Router: You can configure the HSRP priority on the secondary router to be higher than the primary router when the primary WAN link goes down. For example, you can set the priority on the secondary router to be 200 once the primary goes down. This can be achieved using an IP SLA track or other means to detect the primary WAN link failure.

2. Preemption Configuration: Ensure that preemption is enabled on the HSRP configuration on the secondary router. Preemption allows the router with the highest priority to take over as the active router once it meets the priority criteria.

3. IP SLA Configuration: You can use IP SLA to track the primary router's WAN link and adjust the HSRP priority on the secondary router if the WAN link goes down. Additionally, you can configure IP SLA to test connectivity to a specific destination and trigger a failover if the primary link fails.

4. Floating Static Route: Set up a floating static route on the secondary router that points to the cellular interface as the next hop. This route will only be active when the primary link goes down, ensuring that traffic is sent over the cellular connection.