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question on HSRP

ilnaiduccna
Level 1
Level 1

Hi,

HSRP will be configure on Fa0/0 am i right?

When serial interface goes down then traffic will be shifted on to standby router as well as Fa0/0 state will be standby to listen am i right?

Here i am getting messages lik without bouncing / fluctuating Serial interface the Fa0/0 changing states from Standby to listen and speak to standby.

Experts can any body look in to this and help out me.

Regards,

Naidu.

12 Replies 12

balsheikh
Level 1
Level 1

Hi Naidu,

i'm not sure what commands had you applied on ur router, if you can paste it here will be perfect to figure out the casue of the problem, anyway, ur config should be similar to this:

Interface fastethernet 0/0

Standby 1 ip x.x.x.x

Standby 1 priority 120 (defaul is 100)

Standby 1 preempt

Standby 1 track serial 0/0 50

note: default decrement value is 20

hope this will help u :)

Hi Belal,

Righ now I am unable to see the config part.

I belive the config has like same as you mentioned in your post.

If no can you guess where will be the miss config.

But my doubt about which I mentioned at top line in my first post like if Serial bouncing then only the HSRP state will be change at Fa0/0 am i right?

Regards,

Naidu :-)

Naidu,

It is very dependant on how you have configured the priorities on the interfaces. I am guessing that fa0/0 would be the preferred link and serial0 is the standby. If the serial0 interface is unstable, and bouncing it will not be in standby while it is down, and fa0/0 is on it's own if there are no other interfaces in the HSRP group. A better explanation of the scenario, as well as configs would be helpful.

Mark

Hi Mark,

Thanks for your reply.

Yes Fa0/0 is the preferred link but how come serial0 is the standby, can you clarify it?

As per my knowledge two Fa0/0 interfaces (with two routers) only participate in HSRP like one (router) is for Active and one (router) is for Standby as per the priority am i right?

And since Serial0 is not bouncing.

Thanks in advance.

Regards,

Naidu :-)

hello,

HSRP is not a routing protocol but it allows to track the state of other interfaces and to dynamically adjust its priority this is the meaning of the command

Standby 1 track serial 0/0 50

if serial 0/0 is down the router decrements its HSRP priority by 50 and the other router can preempt (if preemption is configured).

If the serial interface is flapping you will see many messages of HSRP changing state from Active to Standby on both routers.

This doesn't mean fas0/0 is not working.

the default decrement for tracking should be 10.

hope to help

Giuseppe

Hi,

I know that HSRP is not routing protocol.

My Fa0/0 is working but I am getting messages from Standby to Active messages.

As you mentioned if the serial interface is flapping you will see many messages of HSRP changing state from Active to Standby on both routers.

Can you tell on which interface we will see the changing states.

Regards,

Naidu.

Your understanding is correct, if serial0 is configured in the HSRP group with the other fa0/0 interfaces.

Mark

Hi Giuseppe, Mark

Thannks for your comments.

I know that HSRP is not routing protocol.

My Fa0/0 is working but I am getting messages from Standby to Active messages.

As you mentioned if the serial interface is flapping you will see many messages of HSRP changing state from Active to Standby on both routers.

Can you tell on which interface we will see the changing states.

Please find the below log messages.

Jun 20 14:03:44 GMT: %HSRP-6-STATECHANGE: FastEthernet0/0.1 Grp 2 state Active -> Speak

Jun 20 14:03:44 GMT: %LINK-3-UPDOWN: Interface Serial0/1/0:0, changed state to down

Jun 20 14:03:45 GMT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1/0:0, changed state to down

Jun 20 14:03:47 GMT: %HSRP-6-STATECHANGE: FastEthernet0/0.2 Grp 3 state Active -> Speak

Jun 20 14:03:53 GMT: %HSRP-6-STATECHANGE: FastEthernet0/0.65 Grp 5 state Speak -> Standby

Jun 20 14:03:54 GMT: %HSRP-6-STATECHANGE: FastEthernet0/0.1 Grp 1 state Speak -> Standby

Jun 20 14:03:54 GMT: %HSRP-6-STATECHANGE: FastEthernet0/0.1 Grp 2 state Speak -> Standby

Jun 20 14:03:57 GMT: %HSRP-6-STATECHANGE: FastEthernet0/0.2 Grp 3 state Speak -> Standby

Jun 20 14:03:59 GMT: %BGP-5-ADJCHANGE: neighbor 62.6.71.169 Down BGP Notification sent

Jun 20 14:03:59 GMT: %BGP-3-NOTIFICATION: sent to neighbor 62.6.71.169 4/0 (hold time expired) 0 bytes

Jun 20 14:05:25 GMT: %CONTROLLER-5-UPDOWN: Controller E1 0/1/0, changed state to up

Jun 20 14:05:27 GMT: %LINK-3-UPDOWN: Interface Serial0/1/0:0, changed state to up

Jun 20 14:05:28 GMT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1/0:0, changed state to up

Jun 20 14:05:28 GMT: %HSRP-6-STATECHANGE: FastEthernet0/0.65 Grp 5 state Standby -> Active

Jun 20 14:05:29 GMT: %HSRP-6-STATECHANGE: FastEthernet0/0.2 Grp 3 state Standby -> Active

Jun 20 14:05:29 GMT: %HSRP-6-STATECHANGE: FastEthernet0/0.1 Grp 1 state Standby -> Active

Jun 20 14:05:29 GMT: %HSRP-6-STATECHANGE: FastEthernet0/0.1 Grp 2 state Standby -> Active

Jun 20 14:05:59 GMT: %BGP-5-ADJCHANGE: neighbor 62.6.71.169 Up

Regards,

Naidu.

Hello Naidu,

as for the log messages you have provided the interface that is monitored = tracked is Serial0/1/0:0 it fails at Jun 20 14:03:44 and it is restored at Jun 20 14:05:28.

During this time interval all the HSRP groups defined on fas0/0 subinterfaces: fas0/0.1 (Grp 1, 2), on fas0/0.2 (Grp. 3) on fas0/0.65 (Grp 5) that have a command standby track Serial0/1/0:0 will experience the following:

group x priority is reduced by ten (or other values if configured)

group x priority is sent out on HSRP hello messages.

the new group x's priority is compared with the priority present on the other router's HSRP messages

As a consequence of group x's priority being less then the received one (and preemption is enabled) the local HSRP state for group x changes from Active to Standby.

So you get :

Jun 20 14:03:47 GMT: %HSRP-6-STATECHANGE: FastEthernet0/0.2 Grp 3 state Active -> Speak

Jun 20 14:03:53 GMT: %HSRP-6-STATECHANGE: FastEthernet0/0.65 Grp 5 state Speak -> Standby

Jun 20 14:03:54 GMT: %HSRP-6-STATECHANGE: FastEthernet0/0.1 Grp 1 state Speak -> Standby

Jun 20 14:03:54 GMT: %HSRP-6-STATECHANGE: FastEthernet0/0.1 Grp 2 state Speak -> Standby

Jun 20 14:03:57 GMT: %HSRP-6-STATECHANGE: FastEthernet0/0.2 Grp 3 state Speak -> Standby

After the interface line protocol comes up again all HSRP groups (that are tracking that serial interface) will recalculate their priority by adding what had been subtracted before.

The new group x's priority is sent out on group x's HSRP hello messages.

Because the new restored priority is higher then the one received from the other router all HSRP groups change state from Standby to Active and you get :

Jun 20 14:05:28 GMT: %HSRP-6-STATECHANGE: FastEthernet0/0.65 Grp 5 state Standby -> Active

Jun 20 14:05:29 GMT: %HSRP-6-STATECHANGE: FastEthernet0/0.2 Grp 3 state Standby -> Active

Jun 20 14:05:29 GMT: %HSRP-6-STATECHANGE: FastEthernet0/0.1 Grp 1 state Standby -> Active

Jun 20 14:05:29 GMT: %HSRP-6-STATECHANGE: FastEthernet0/0.1 Grp 2 state Standby -> Active

two routers perform an active router election based on who has the higher priority.

Active router identity can change over time if a tracked=monitored interface changes state and preemption is enabled on the companion router.

In this case you have multiple HSRP groups defined on different subinterfaces (= different vlans) and this produces a multiplication effect of this error messages.

hope to help

Giuseppe

raj_ctech1103
Level 1
Level 1

Hi Naidu,

Have u configured tracking in HSRP configuration,If so can u pls tell me why?If it is not necessary then remove the tracking command.ur problem get solved.

Raj

Hi Raj,

Thank you so much for your early reply.

Unfartunately I am unable to chekc config,

Can you just give me some info about tracking command like what it will do?

Regards,

Naidu :-)

It appears that you are using interface tracking. I understand that you don't have access to the config. Here is a reference guide for HSRP interface tracking.

http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a0080094a91.shtml#intracking

Mark

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