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Community Member

switch to standby router

I have 2 1841 routers configured as active/standby and are working without problem.

For some reason the active router switched over to the standby router. I verified the previous active router is fine.

How can I manually force the standby router to switch over to the original active router?

7 REPLIES
Silver

Re: switch to standby router

use the following command in the config to have it switch back when active comes back online.

standby group-# preempt

See the following website if you want to see an example of this command. http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a0080094e8c.shtml

Hope this helps.

Steve

Community Member

Re: switch to standby router

Thanks. I read that earlier and it makes sense.

Router-A (*this router is currently marked as active*)

standby 1 ip 192.168.1.1

standby 1 priority 90

standby 1 preempt

standby 1 track FastEthernet0/1

Router-B

standby 1 ip 192.168.1.1

standby 1 priority 20

standby 1 track FastEthernet0/1

So if I configure Router-B with the preempt command...it will fail back to the Router-A as active? Would I then take the preempt out of Router-B?

Router-A was originally in active state and then moved to Router-B for some reason.

Hall of Fame Super Gold

Re: switch to standby router

Kevin

Thanks for posting the additional detail. Given what is posted here RouterA should have regained the active role. I do not believe that it is an issue with preempt. If RouterA has not become active then there must be something else going on. It would be helpful if you would post the output of show standby from both routers. It would also be helpful to see the results of show cdp neighbor detail from both routers.

As a side note I do not believe that the track feature will work the way you want it to work with this configuration. First, for track to work properly you should configure preempt on RouterB. Also with the track feature when it determines that the tracked interface has gone down it will lower the priority of standby (by default it lowers by 10 and your config does not show any alteration of the decrease value). With a difference in priority of 70 between these routers the decrease caused by track will not cause the backup router to take over. If you want the track feature to work I would suggest that you set the priority of RouterA to 90 and set the priority of RouterB to 85. This will allow the track feature to work as intended.

HTH

Rick

Community Member

Re: switch to standby router

Here is the add'tl info:

Router-B (**this is currently standby and was originally active)

interface FastEthernet0/0

standby 1 ip 192.168.1.1

standby 1 priority 20

standby 1 track FastEthernet0/1

FastEthernet0/0 - Group 1

State is Standby

6 state changes, last state change 6w4d

Virtual IP address is 192.168.1.1

Active virtual MAC address is 0000.0c07.ac01

Local virtual MAC address is 0000.0c07.ac01 (v1 default)

Hello time 3 sec, hold time 10 sec

Next hello sent in 2.780 secs

Preemption disabled

Active router is 192.168.1.2, priority 90 (expires in 7.908 sec)

Standby router is local

Priority 20 (configured 20)

Track interface FastEthernet0/1 state Up decrement 10

IP redundancy name is "hsrp-Fa0/0-1" (default)

Router-A (**this router is currently marked as active; Router B is the original active router)

interface FastEthernet0/0

standby 1 ip 192.168.1.1

standby 1 priority 90

standby 1 preempt

standby 1 track FastEthernet0/1

FastEthernet0/0 - Group 1

State is Active

5 state changes, last state change 6w4d

Virtual IP address is 192.168.1.1

Active virtual MAC address is 0000.0c07.ac01

Local virtual MAC address is 0000.0c07.ac01 (v1 default)

Hello time 3 sec, hold time 10 sec

Next hello sent in 2.492 secs

Preemption enabled

Active router is local

Standby router is 192.168.1.3, priority 20 (expires in 8.364 sec)

Priority 90 (configured 90)

Track interface FastEthernet0/1 state Up decrement 10

IP redundancy name is "hsrp-Fa0/0-1" (default)

Hall of Fame Super Gold

Re: switch to standby router

Kevin

I do not understand what problem you are experiencing. But based on what you have posted HSRP is working exactly as it should. RouterA is configured with priority 90 and with preempt while RouterB is configured with priority 20 (and without preempt). The way that HSRP is intended to work is that if a router in the HSRP group has a higher priority and has preempt, then that router becomes the active router. And this is the case in what you posted.

I can not speak to what originally existed, or why routerB was the active router in the past. But based on what you have posted what you are now seeing is the expected and correct behavior of HSRP.

HTH

Rick

Community Member

Re: switch to standby router

what I would like to do is force a switch back to the other router to be active. The current router that is active has a slower line.

from your previous post, it sounds like I need to add the preempt to the other router that is in standby currently

Hall of Fame Super Gold

Re: switch to standby router

Kevin

The router that you want to be active in normal circumstances should have the higher priority.

For various reasons I believe that you should include preempt in the config on both routers.

And if you want the track feature to work the difference in priority between the active router and the standby router should be less than 10 (or you should specify a larger amount of change in the track command - the show standby output that you posted clearly shows that it will change by 10 points if the interface goes down).

HTH

Rick

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