Need Help Configuring HSRP

Answered Question
Oct 26th, 2009
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I've setup a test environment using GNS3 with 2 Cisco 2691 routers (same IOS)connected to the generic L2 switch.


Router_A = Primary

Router_B = Backup



Results:

- Router_A becomes the Active router just fine after it's first configured for HSRP


- When Router_B is configured for HSRP, it immediately took over the ACTIVE role, and changes Router_A to STANDBY status.


- When I shut down the FA0/0 on Router_B, Rourter_A changes its state from STANDBY to ACTIVE


- When I re-enable the FA0/0 on Router_B, its state becomes ACTIVE and changes Rourter_A to STANDBY state.


- I've tried assigning Router_A with higher IP address (192.168.23.4), but it makes no difference.


My question is how can I make Router_A to be the ACTIVE router all the time until it fails ,then Router_B would assume the ACTIVE role?




Router_A (Primary)

interface FastEthernet0/0

ip address 192.168.23.2 255.255.255.0

duplex auto

speed auto

standby priority 105

standby 44 ip 192.168.23.1

standby 44 timers 1 3

standby 44 preempt

standby 44 authentication CISCO

standby 44 track Serial0/0


Router_A# sh standby

FastEthernet0/0 - Group 44

State is Standby

19 state changes, last state change 00:03:29

Virtual IP address is 192.168.23.1

Active virtual MAC address is 0000.0c07.ac2c

Local virtual MAC address is 0000.0c07.ac2c (v1 default)

Hello time 1 sec, hold time 3 sec

Next hello sent in 0.888 secs

Authentication text, string "CISCO"

Preemption enabled

Active router is 192.168.23.3, priority 100 (expires in 2.800 sec)

Standby router is local

Priority 95 (configured 105)

Track interface Serial0/0 state Down decrement 10

IP redundancy name is "hsrp-Fa0/0-44" (default)


Router_B (Backup)

interface FastEthernet0/0

ip address 192.168.23.3 255.255.255.0

duplex auto

speed auto

standby 44 priority 100

standby 44 ip 192.168.23.1

standby 44 timers 1 3

standby 44 priority 101

standby 44 preempt

standby 44 authentication CISCO

standby 44 track Serial0/0


Router_B#sh standby

FastEthernet0/0 - Group 44

State is Active

23 state changes, last state change 00:01:16

Virtual IP address is 192.168.23.1

Active virtual MAC address is 0000.0c07.ac2c

Local virtual MAC address is 0000.0c07.ac2c (v1 default)

Hello time 1 sec, hold time 3 sec

Next hello sent in 0.704 secs

Authentication text, string "CISCO"

Preemption enabled

Active router is local

Standby router is 192.168.23.2, priority 95 (expires in 2.784 sec)

Priority 100 (default 100)

Track interface Serial0/0 state Up decrement 10

IP redundancy name is "hsrp-Fa0/0-44" (default)


Thanks for your input.


Hieu

Correct Answer by slmansfield about 7 years 6 months ago

It looks like you're tracking a serial interface on router A, which is down, so the priority on router A drops 10 points lower. If router B has a priority of 100, it will have a higher priority than the dropped priority of router A, which ends up to be 95. If you want router B to only take over when router A is down, I'd remove the tracking of the serial0/0 interface on router A.

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Correct Answer
slmansfield Mon, 10/26/2009 - 12:14
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It looks like you're tracking a serial interface on router A, which is down, so the priority on router A drops 10 points lower. If router B has a priority of 100, it will have a higher priority than the dropped priority of router A, which ends up to be 95. If you want router B to only take over when router A is down, I'd remove the tracking of the serial0/0 interface on router A.

Hieu Cao Mon, 10/26/2009 - 12:51
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You pointed out exactly what the problem was.


Router_A is the ACTIVE router when I do one of the two things:

1. Remove the tracking for s0/0 in Router_A when the serial link is down in this case


or


2. Leave the tracking for s0/0 in Router_A in place and make sure the serial link is up where the interface s0/0 is connected to.



Thank you Susan very much for your help!


Hieu

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