RE: HSRP preempt

Mohammad is correct, it will not preempt.

A tracking failure is different than a group failure. Suppose the primary router has priority 100 and the standby has 90, the primary is tracking an object that will decrement its priority by 20, and preemption is *off*. The tracked object goes down and the primary's priority is now 80, which is lower than standby. Since the routers are still receiving keepalives from each other, this does not count as a group failure, and the standby does *not* take over as the active router. Even though its priority is now higher than the primary, it cannot preempt.

In the case though that the entire primary router crashes, the standby *will* promote itself to active, and when the original active router loads it will not preempt the new active router even though its priority is higher.

Brian McGahan, CCIE #8593 (R&S/SP/Security)
bmcgahan_at_INE.com

Internetwork Expert, Inc.
http://www.INE.com

-----Original Message-----
From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of Mohammad Mousa
Sent: Monday, November 26, 2012 8:48 AM
To: Mohammad Mousa
Cc: Tony Singh; Tauseef Khan; Cisco certification
Subject: Re: HSRP preempt

(STANDBY)R1---R2(ACTIVE)

R1

---
interface FastEthernet0/0
ip address 12.0.0.1 255.255.255.0
duplex auto
speed auto
standby 1 ip 12.0.0.254
R2
---
track 1 ip route 1.1.1.1 255.255.255.255 reachability
interface FastEthernet0/0
ip address 12.0.0.2 255.255.255.0
duplex auto
speed auto
standby 1 ip 12.0.0.254
standby 1 track 1 decrement 20
OUTPUT:
I shut the loopback interface of R1, which led the Tracker to be down on R2!
R2(config)#do sh standby
FastEthernet0/0 - Group 1
  State is Active
    1 state change, last state change 00:05:06
  Virtual IP address is 12.0.0.254
  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 2.208 secs
  Preemption disabled
  Active router is local
  Standby router is 12.0.0.1, priority 100 (expires in 7.600 sec)
  Priority 80 (default 100)
    Track object 1 state Down decrement 20
  Group name is "hsrp-Fa0/0-1" (default)
---
R2(config)#do sh track
Track 1
IP route 1.1.1.1 255.255.255.255 reachability Reachability is Down (no route)
2 changes, last change 00:01:43
First-hop interface is unknown
Tracked by:
HSRP FastEthernet0/0 1
On Nov 26, 2012, at 5:19 PM, Mohammad Mousa wrote:
> Guys,
> 
> I just Labed it up, as I said the standby router didn't take the active role unless I configured the preemption!
> If you interested to see the configuration, let me post the configs.
> 
> 
> --
> Mohammad Mousa
> CCIE #36990
> 
> 
> 
> 
> 
> 
> On Nov 26, 2012, at 4:31 PM, Tony Singh wrote:
> 
>> No preemption is required for switch to occur , lab it
>> 
>> --
>> BR
>> 
>> Tony
>> 
>> Sent from my iPhone on 3
>> 
>> On 26 Nov 2012, at 13:26, Tauseef Khan <tasneemjan_at_googlemail.com> wrote:
>> 
>>> If the priority is same on 2 routers participating in standby group 
>>> 1 with default priority of 100 and no preempt enable an either of 
>>> the routers and a standby track 1 reach dec 10 is configured. I f 
>>> the track object goes down will it cause an election between the routers.
>>> Regards
>>> 
>>> 
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