HSRP both become active once tracked interface goes down

sanjeevreddyallala · ‎06-25-2010

Hi team,

I was doing a fail-over testing for several sites for a customer.(dual CE router setup)

I have two routers 08R & 09R with following HSRP config.

with this configuration 08R is active & 09R is secondary.. all good

but when I shutdown the Serial link on active router(08R). both become active and standby unknown

they can ping each other, checked ARP table, all good.

also removed track statement on backup router (09R) but no joy...

put the debug on

Please advise.

08R#sh run int f0/0

ip address 10.58.0.29 255.255.255.0

standby 1 ip 10.58.0.30 <---hsrp ip
standby 1 priority 105<------------------- when s0/0/0 down, becomes 95
standby 1 preempt
standby 1 track Serial0/0/0.100

09R#sh run int f0/0

ip address 10.58.0.31 255.255.255.0

standby 1 ip 10.58.0.30
standby 1 priority 101 <-------
standby 1 preempt

standby 1 track Serial0/1/0:0.100<-----------also tracking its own serial interface (removed this as its not required but still not working)

Debug on 08R

-----------

Jun 25 08:51:33.554 GMT: HSRP: Fa0/0 Grp 1 Hello out 10.58.0.29 Active pri 95 vIP 10.58.0.30 <---sending hellos with lower priority 95, no in pkts
Jun 25 08:51:36.554 GMT: HSRP: Fa0/0 Grp 1 Hello out 10.58.0.29 Active pri 95 vIP 10.58.0.30
Jun 25 08:51:37.978 GMT: HSRP: Fa0/0 Grp 1 Hello out 10.58.0.29 Active pri 95 vIP 10.58.0.30

Debug on 09R

--------------------

Jun 25 08:52:00.542 GMT: HSRP: Fa0/0 Grp 1 Hello out 10.58.0.31 Active pri 101 vIP 10.58.0.30
Jun 25 08:52:00.542 GMT: HSRP: Fa0/0 Grp 1 Hello in 10.58.0.29 Active pri 95 vIP 10.58.0.30
Jun 25 08:52:00.542 GMT: HSRP: Fa0/0 Grp 1 Coup out 10.58.0.31 Active pri 101 vIP 10.58.0.30
Jun 25 08:52:00.542 GMT: HSRP: Fa0/0 Grp 1 Hello out 10.58.0.31 Active pri 101 vIP 10.58.0.30
Jun 25 08:52:03.542 GMT: HSRP: Fa0/0 Grp 1 Hello out 10.58.0.31 Active pri 101 vIP 10.58.0.30
Jun 25 08:52:03.542 GMT: HSRP: Fa0/0 Grp 1 Hello in 10.58.0.29 Active pri 95 vIP 10.58.0.30
Jun 25 08:52:03.542 GMT: HSRP: Fa0/0 Grp 1 Coup out 10.58.0.31 Active pri 101 vIP 10.58.0.30
Jun 25 08:52:03.542 GMT: HSRP: Fa0/0 Grp 1 Hello out 10.58.0.31 Active pri 101 vIP 10.58.0.30

Richard Burts · ‎06-27-2010

Sanjeev

I am not sure how it is happening but when you produce the failure of the serial interface of O8R something is also impacting the ability of the routers to communicate with each other. It results in one way communication between O8R and O9R. The debug that you posted is pretty clear that O9R is sending and receiving HSRP updates (and knows that O8R has lowered its priority). But O8R is send but not receiving HSRP updates. I wonder in this situation what show cdp neighbor would show about communication between these two?

HTH

Rick

HTH

Rick

sanjeevreddyallala · ‎06-30-2010

"standy use-bia" fixed the issue. but still dont understand what was the problem.

what causing HSRP to behave this way?(Layer 2 and layer connectivity there: arp table is ok, ping is fine between them via LAN. connected to same switch, does it matter if they connected to different switches?)

any thoughts?

abersven · ‎06-28-2010

Try this:

Router 08R Configuration

!

track 100 interface Serial0/0/0.100 ip routing

!

interface FastEthernet0/0

ip address 10.58.0.29 255.255.255.0

standby 1 ip 10.58.0.30

standby 1 preempt

standby 1 priority 105

standby 1 track 100 decrement 10

!

Router 09R Configuration

!

track 100 interface Serial0/1/0:0.100 ip routing

!

interface FastEthernet0/0

ip address 10.58.0.31 255.255.255.0

standby 1 ip 10.58.0.30

standby 1 preempt

standby 1 priority 101

standby 1 track 100 decrement 10

!

Ref.: CCO

/André

sanjeevreddyallala · ‎06-30-2010

I cant use enhanced object tracking just like that(ip routing).

I just want to understand what was the problem.