06-21-2007 12:18 PM - edited 03-03-2019 05:32 PM
I have 2 2811 routers with 1 T1 in each connecting to the main site. I'm running HSRP between the 2 routers and want to configure HSRP Object Tracking to track line protocol on the serial link so when the T1 goes down on the primary router, it will switch to the standby. My question is, how do I configure it, so it switches back to the original primary router once the link is up.
Here's a sample of my config:
Router A (primary):
track 100 interface Serial0/0/0:1 line-protocol
interface FastEthernet0/0
ip address x.x.x.2 255.255.255.0
standby 1 ip x.x.x.1
standby 1 priority 130
standby 1 preempt
standby 1 track 100 decrement 30
How do I configure my standby router B?
Solved! Go to Solution.
06-22-2007 06:12 AM
Hi Gary,
I just tested in my lab, It is not required to put "standby 1 track 100 decrement" command on router B, Since you are only tracking the T1 link of router A.This commnad need only under router A's interfacefa0/0.
So the config will be as follows
Router A
=========
track 100 interface Serial0/0/0:1 line-protocol
interface FastEthernet0/0
ip address x.x.x.1 255.255.255.0
standby 1 ip x.x.x.3
standby 1 priority 130
standby 1 preempt
standby 1 track 100 decrement 30
Router B
=========
interface FastEthernet0/0
ip address x.x.x.2 255.255.255.0
standby 1 ip x.x.x.3
standby 1 priority 110
standby 1 preempt
06-21-2007 01:24 PM
Hi Gary,
you can configure router B as follows
interface FastEthernet0/0
ip address x.x.x.3 255.255.255.0
standby 1 ip x.x.x.1
standby 1 priority 120
standby 1 preempt
"standby 1 track 100 decrement30" means when the T1 link goes down it will decrease the priority from 130 to 100. Then router B will have the highest priority and will be active. when the T1 will up the preempt command is already there in rouer A to switch back and become active.
06-22-2007 05:31 AM
Hello Girish,
The Cisco document on Enhanced Object Tracking says that for Router B we should also put the decrement command. So, both Router A and Router B configs look the same except for the HSRP priority value. That confuses me, why is the standby router configured to decrement as well.
So, the config for router B would look like this:
track 100 interface Serial0/0/0:1 line-protocol
interface FastEthernet0/0
ip address x.x.x.3 255.255.255.0
standby 1 ip x.x.x.1
standby 1 priority 110
standby 1 preempt
standby 1 track 100 decrement 30
06-22-2007 06:12 AM
Hi Gary,
I just tested in my lab, It is not required to put "standby 1 track 100 decrement" command on router B, Since you are only tracking the T1 link of router A.This commnad need only under router A's interfacefa0/0.
So the config will be as follows
Router A
=========
track 100 interface Serial0/0/0:1 line-protocol
interface FastEthernet0/0
ip address x.x.x.1 255.255.255.0
standby 1 ip x.x.x.3
standby 1 priority 130
standby 1 preempt
standby 1 track 100 decrement 30
Router B
=========
interface FastEthernet0/0
ip address x.x.x.2 255.255.255.0
standby 1 ip x.x.x.3
standby 1 priority 110
standby 1 preempt
06-22-2007 06:24 AM
Thank you sir! Really appreciate your help!
06-22-2007 02:33 AM
Hi ,
The config of both the routers is as below...
** connect the f0/1 of both the routers back to abck and assign ip address to both fastethernet interfaces...
Why we are doing it is whenever T1 connecting to router A goes down the traffic will flow through as below...
RTR A (f0/1) -> (F0/1) RTR B (Serail)-->mainoffice...
RTRA :
int f0/0
ip address x.x.x.2 255.255.255.0
standby 1 ip x.x.x.1
standby 1 preempt
standby 1 priority 150
standby track serial 0/0/0:1
int f0/1
ip address x.x.x.1 255.255.255.0
ip route x.x.x.x x.x.x.x s0/0/0:1
ip route x.x.x.x x.x.x.x f0/1 30 (flotic static route) (whenever serail of RTR A goes down traffic will be flown as shown above..)
RTR B :
int f0/0
ip address x.x.x.3 255.255.255.0
standby 1 ip x.x.x.1
standby 1 preempt
standby track serial 0/0/0:1
int f0/1
ip address x.x.x.2 255.255.255.0
ip route x.x.x.x x.x.x.x serial 0/0/0:1
when you see the above config...RTR B HSRP priority is default one i.e 100...
RTR A is the active router and router B is the standby router...
NOte : whenever T1 of RTR A comes back then Traffic switches to RTR A from RTR B because RTR A has Highest HSRP priority..
Thanks,
Satish
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