Re: HSRP active router tells standby to take over when being

We have had quite a few discussions about this particular feature. You have multiple scenarios: hardware failure of one of the routers, upstream failure, downstream failure, power outage, and config changes being made (software upgrades, etc).

I'm interested to know which scenario you were testing when you did this?

After a lot of debate, we decided that triggering a failover before doing maintenance wasn't really required if we were taking the box offline. If just wanting to reroute around it you have to affect routing as well as HSRP.

I've seen some interesting solutions for solving some of the true failure scenarios though...

On Sep 22, 2011, at 6:40 AM, Pavel Bykov wrote:

> Nice post.
> As the worker bee pointed out, the reload command triggered graceful
> shutdown. Reload is only a command, and its interpretation is really up to a
> parser. IOS could draw an ASCII flower upon entering it :)
> Usually, it is a good idea to failover test using more real scenarios (test
> crash, physical manipulation)
> It'd be interesting to trigger resign message some other way, e.g. through a
> fast detection mechanism, or a triggered mechanism (like EEM).
>
> Thanks for sharing, Joseph.
> Regards,
> Pavel
> On Wed, Sep 21, 2011 at 6:15 AM, Joseph L. Brunner
> <joe_at_affirmedsystems.com>wrote:
>
>> One cool fact I thought I would share with the group - Understanding the
>> HSRP
>> resign message...
>>
>> This evening I'm testing various failover scenarios and I have my primary
>> (HSRP active) router (.2) the HSRP primary (for .1) on an external segment
>> (where 2 ASA's default to the HSRP virtual address (.11 , .10)
>>
>> I don't use standby tracking on the primary router - it's simply tracking
>> its
>> local ISP connection default route via an SLA ping of the ISP adjacent
>> neighbor on metro-E and track object. I have a backup default route, AD
>> 254,
>> to the Standby router (.3) on the segment. If the primary router is up, but
>> has no valid default route (cause it can't ping the adjacent ISP) it routes
>> all traffic to standby router.
>>
>> So I started my failover testing by rebooting primary router and doing a
>> continuous ping of 4.2.2.2. Well, no pings were missed during the reboot!!!
>> (I
>> expected about 10 missed pings as the standby router became hsrp primary
>> and
>> took over .1, the default gateway of the ASA's). (if you're sharp you
>> caught
>> the fact we're obviously natting the first public range to a second public
>> range on the standby router to go out a different ISP)
>>
>> Here is the debug output on the HSRP standby router during the primary's
>> reboot (watch for the "resign rcvd" where the primary RESIGNS and allows
>> the
>> standby to become active MUCH FASTER than the timers)
>>
>> kcf1515-edge-rtr2#debug standby
>> HSRP debugging is on
>> kcf1515-edge-rtr2#
>> Sep 21 04:08:15.504: HSRP: Gi0/0 Grp 1 Hello in 174.58.91.2 Active pri
>> 150
>> vIP 174.58.91.1
>> Sep 21 04:08:15.824: HSRP: Gi0/0 Grp 1 Hello out 174.58.91.3 Standby pri
>> 100
>> vIP 174.58.91.1
>> Sep 21 04:08:18.824: HSRP: Gi0/0 Grp 1 Hello out 174.58.91.3 Standby pri
>> 100
>> vIP 174.58.91.1
>> Sep 21 04:08:19.352: HSRP: Gi0/0 Grp 1 Hello in 174.58.91.2 Active pri
>> 150
>> vIP 174.58.91.1
>> Sep 21 04:08:21.516: HSRP: Gi0/0 Grp 1 Resign in 174.58.91.2 Active pri
>> 150
>> vIP 174.58.91.1
>> Sep 21 04:08:21.516: HSRP: Gi0/0 Grp 1 Standby: i/Resign rcvd
>> (150/174.58.91.2)
>> Sep 21 04:08:21.516: HSRP: Gi0/0 Grp 1 Active router is local, was
>> 174.58.91.2
>> Sep 21 04:08:21.516: HSRP: Gi0/0 Grp 1 Standby router is unknown, was local
>> Sep 21 04:08:21.516: HSRP: Gi0/0 Grp 1 Standby -> Active
>> Sep 21 04:08:21.516: %HSRP-5-STATECHANGE: GigabitEthernet0/0 Grp 1 state
>> Standby -> Active
>> Sep 21 04:08:21.516: HSRP: Gi0/0 Grp 1 Redundancy "hsrp-Gi0/0-1" state
>> Standby
>> -> Active
>> Sep 21 04:08:21.516: HSRP: Gi0/0 Redundancy server "hsrp-Gi0/0-1" update,
>> Standby -> Active
>> Sep 21 04:08:21.516: HSRP: Gi0/0 Redirect adv out, Active, active 1 passive
>> 1
>> Sep 21 04:08:21.516: HSRP: Gi0/0 Grp 1 Hello out 174.58.91.3 Active pri
>> 100
>> vIP 174.58.91.1
>> Sep 21 04:08:24.516: HSRP: Gi0/0 Grp 1 Hello out 174.58.91.3 Active pri
>> 100
>> vIP 174.58.91.1
>> Sep 21 04:08:24.516: HSRP: Gi0/0 Grp 1 Redundancy group hsrp-Gi0/0-1 state
>> Active -> Active
>> Sep 21 04:08:27.516: HSRP: Gi0/0 Grp 1 Hello out 174.58.91.3 Active pri
>> 100
>> vIP 174.58.91.1
>> Sep 21 04:08:27.516: HSRP: Gi0/0 Grp 1 Redundancy group hsrp-Gi0/0-1 state
>> Active -> Active
>> kcf1515-edge-rtr2#
>> Sep 21 04:08:30.076: HSRP: Gi0/0 Grp 1 Hello out 174.58.91.3 Active pri
>> 100
>> vIP 174.58.91.1
>> Sep 21 04:08:30.516: HSRP: Gi0/0 Grp 1 Hello out 174.58.91.3 Active pri
>> 100
>> vIP 174.58.91.1
>> kcf1515-edge-rtr2#un all
>> All possible debugging has been turned off
>>
>>
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Received on Thu Sep 22 2011 - 17:20:34 ART