HSRP active router tells standby to take over when being

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 Wed Sep 21 2011 - 04:15:54 ART