The IOS implementation of HSRP supports the debug
command. Enabling debug displays HSRP state changes and debug output regarding
the transmission and receipt of HSRP packets. To enable HSRP debugging, enter
this command in privileged EXEC mode:
Switch#debug
standby
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CAUTION:
Because debugging output is assigned high priority in the CPU
process, this command can render the system unusable.
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Example: HSRP Debugging on Negotiating for Role of Active
Router
This example displays the debug standby
command output as the DSW111 router with the IP address 172.16.1.111
initializes and negotiates for the role of the active router:
*Mar 8 20:34:10.221: SB11: Vl11 Init: a/HSRP
enabled
*Mar 8 20:34:10.221: SB11: Vl11 Init ->
Listen
*Mar 8 20:34:20.221: SB11: Vl11 Listen: c/Active timer
expired (unknown)
*Mar 8 20:34:20.221: SB11: Vl11 Listen ->
Speak
*Mar 8 20:34:20.221: SB11: Vl11 Hello out 172.16.11.111
Speak pri 100 ip 172.16.11.115
*Mar 8 20:34:23.101: SB11: Vl11
Hello out 172.16.11.111 Speak pri 100 ip 172.16.11.115
*Mar 8
20:34:25.961: SB11: Vl11 Hello out 172.16.11.111 Speak pri 100 ip
172.16.11.115
*Mar 8 20:34:28.905: SB11: Vl11 Hello out
172.16.11.111 Speak pri 100 ip 172.16.11.115
*Mar 8
20:34:30.221: SB11: Vl11 Speak: d/Standby timer expired
(unknown)
*Mar 8 20:34:30.221: SB11: Vl11 Standby router is
local
*Mar 8 20:34:30.221: SB11: Vl11 Speak ->
Standby
*Mar 8 20:34:30.221: SB11: Vl11 Hello out
172.16.11.111 Standby pri 100 ip 172.16.11.115
*Mar 8
20:34:30.221: SB11: Vl11 Standby: c/Active timer expired
(unknown)
*Mar 8 20:34:30.221: SB11: Vl11 Active router is
local
*Mar 8 20:34:30.221: SB11: Vl11 Standby router is
unknown, was local
*Mar 8 20:34:30.221: SB11: Vl11 Standby
-> Active
*Mar 8 20:34:30.221: %STANDBY-6-STATECHANGE:
Vlan11 Group 11 state Standby -> Active
*Mar 8
20:34:30.221: SB11: Vl11 Hello out 172.16.11.111 Active pri 100 ip
172.16.11.115
To disable the debugging feature, enter
either the no debug standby command or the no
debug all command.
Example: HSRP Debugging on First and Only Router on Subnet
In this
example, because DSW111 (172.16.11.111) is the only router on the subnet and
because it is not configured for preempt, this router will go through all the
HSRP states before becoming the active router. Notice at time stamp Mar 8
20:34:10.221 that the interface comes up and DSW111 enters the listen state.
The router stays in the listen state for the holdtime of 10 seconds. DSW111
then goes into the speak state at time stamp Mar 8 20:34:20.221 for 10 seconds.
When the router is speaking, it sends its state out every 3 seconds according
to its hello interval. After 10 seconds in speak state, the router has
determined that there is no standby router at time-stamp Mar 8 20:34:30.221 and
enters the standby state. The router has also determined that there is not an
active router; therefore, the router immediately enters the active state at
time stamp Mar 8 20:34:30.221. From then on, the active router will send
itsactive state hello message every 3 seconds. Because there are no other
routers on this broadcast domain, there are no hellos being received.
DSW111(config)#interface vlan
11
DSW111(config-if)#no shut
*Mar 8 20:34:08.925: %SYS-5-CONFIG_I: Configured from console
by console
*Mar 8 20:34:10.213: %LINK-3-UPDOWN: Interface
Vlan11, changed state to up
*Mar 8 20:34:10.221: SB: Vl11
Interface up
*Mar 8 20:34:10.221: SB11: Vl11 Init: a/HSRP
enabled
*Mar 8 20:34:10.221: SB11: Vl11 Init ->
Listen
*Mar 8 20:34:11.213: %LINEPROTO-5-UPDOWN: Line protocol
on Interface Vlan11, changed state to up
*Mar 8 20:34:20.221:
SB11: Vl11 Listen: c/Active timer expired (unknown)
*Mar 8
20:34:20.221: SB11: Vl11 Listen -> Speak
*Mar 8
20:34:20.221: SB11: Vl11 Hello out 172.16.11.111 Speak pri 100 ip
172.16.11.115
*Mar 8 20:34:23.101: SB11: Vl11 Hello out
172.16.11.111 Speak pri 100 ip 172.16.11.115
*Mar 8
20:34:25.961: SB11: Vl11 Hello out 172.16.11.111 Speak pri 100 ip
172.16.11.115
*Mar 8 20:34:28.905: SB11: Vl11 Hello out
172.16.11.111 Speak pri 100 ip 172.16.11.115
*Mar 8
20:34:30.221: SB11: Vl11 Speak: d/Standby timer expired
(unknown)
*Mar 8 20:34:30.221: SB11: Vl11 Standby router is
local
*Mar 8 20:34:30.221: SB11: Vl11 Speak ->
Standby
*Mar 8 20:34:30.221: SB11: Vl11 Hello out
172.16.11.111 Standby pri 100 ip 172.16.11.115
*Mar 8
20:34:30.221: SB11: Vl11 Standby: c/Active timer expired
(unknown)
*Mar 8 20:34:30.221: SB11: Vl11 Active router is
local
*Mar 8 20:34:30.221: SB11: Vl11 Standby router is
unknown, was local
*Mar 8 20:34:30.221: SB11: Vl11 Standby
-> Active
*Mar 8 20:34:30.221: %STANDBY-6-STATECHANGE:
Vlan11 Group 11 state Standby -> Active
*Mar 8
20:34:30.221: SB11: Vl11 Hello out 172.16.11.111 Active pri 100 ip
172.16.11.115
*Mar 8 20:34:33.085: SB11: Vl11 Hello out
172.16.11.111 Active pri 100 ip 172.16.11.115
*Mar 8
20:34:36.025: SB11: Vl11 Hello out 172.16.11.111 Active pri 100 ip
172.16.11.115
*Mar 8 20:34:38.925: SB11: Vl11 Hello out
172.16.11.111 Active pri 100 ip 172.16.11.115
Example:
HSRP on NonPreempt Configured Router Coming Up
Router DSW111
(172.16.11.111) is configured with a priority of 100. This priority is higher
than the priority of the current active router DSW112 (172.16.11.112), which
has a priority of 50. Note that router DSW111 is not configured with preempt.
Only when a router is configured with preempt will a router with a higher
priority immediately become the active router. After router DSW111 goes through
the HSRP initialization states, it will come up as the standby router.
DSW111(config)#interface vlan
11
DSW111(config-if)#no shut
*Mar 1 00:12:16.871: SB11: Vl11 Hello in 172.16.11.112 Active
pri 50 ip 172.16.11.115
*Mar 1 00:12:16.871: SB11: Vl11 Active
router is 172.16.11.112
*Mar 1 00:12:16.891: %SYS-5-CONFIG_I:
Configured from console by console
*Mar 1 00:12:18.619:
%LINK-3-UPDOWN: Interface Vlan11, changed state to up
*Mar 1
00:12:18.623: SB: Vl11 Interface up
*Mar 1 00:12:18.623: SB11:
Vl11 Init: a/HSRP enabled
*Mar 1 00:12:18.623: SB11: Vl11 Init
-> Listen
*Mar 1 00:12:19.619: %LINEPROTO-5-UPDOWN: Line
protocol on Interface Vlan11, changed state to up
*Mar 1
00:12:19.819: SB11: Vl11 Hello in 172.16.11.112 Active pri 50 ip
172.16.11.115
*Mar 1 00:12:19.819: SB11: Vl11 Listen: h/Hello
rcvd from lower pri Active router (50/172.16.11.112)
*Mar 1
00:12:22.815: SB11: Vl11 Hello in 172.16.11.112 Active pri 50 ip
172.16.11.115
*Mar 1 00:12:22.815: SB11: Vl11 Listen: h/Hello
rcvd from lower pri Active router (50/172.16.11.112)
*Mar 1
00:12:25.683: SB11: Vl11 Hello in 172.16.11.112 Active pri 50 ip
172.16.11.115
*Mar 1 00:12:25.683: SB11: Vl11 Listen: h/Hello
rcvd from lower pri Active router (50/172.16.11.112)
*Mar 1
00:12:28.623: SB11: Vl11 Listen: d/Standby timer expired
(unknown)
*Mar 1 00:12:28.623: SB11: Vl11 Listen ->
Speak
*Mar 1 00:12:28.623: SB11: Vl11 Hello out 172.16.11.111
Speak pri 100 ip 172.16.11.115
*Mar 1 00:12:28.659: SB11: Vl11
Hello in 172.16.11.112 Active pri 50 ip 172.16.11.115
*Mar 1
00:12:28.659: SB11: Vl11 Speak: h/Hello rcvd from lower pri Active router
(50/172.16.11.112)
*Mar 1 00:12:31.539: SB11: Vl11 Hello in
172.16.11.112 Active pri 50 ip 172.16.11.115
*Mar 1
00:12:31.539: SB11: Vl11 Speak: h/Hello rcvd from lower pri Active router
(50/172.16.11.112)
*Mar 1 00:12:31.575: SB11: Vl11 Hello out
172.16.11.111 Speak pri 100 ip 172.16.11.115
*Mar 1
00:12:34.491: SB11: Vl11 Hello in 172.16.11.112 Active pri 50 ip
172.16.11.115
*Mar 1 00:12:34.491: SB11: Vl11 Speak: h/Hello
rcvd from lower pri Active router (50/172.16.11.112)
*Mar 1
00:12:34.547: SB11: Vl11 Hello out 172.16.11.111 Speak pri 100 ip
172.16.11.115
*Mar 1 00:12:37.363: SB11: Vl11 Hello in
172.16.11.112 Active pri 50 ip 172.16.11.115
*Mar 1
00:12:37.363: SB11: Vl11 Speak: h/Hello rcvd from lower pri Active router
(50/172.16.11.112)
*Mar 1 00:12:37.495: SB11: Vl11 Hello out
172.16.11.111 Speak pri 100 ip 172.16.11.115
*Mar 1
00:12:38.623: SB11: Vl11 Speak: d/Standby timer expired
(unknown)
*Mar 1 00:12:38.623: SB11: Vl11 Standby router is
local
*Mar 1 00:12:38.623: SB11: Vl11 Speak ->
Standby
*Mar 1 00:12:38.623: SB11: Vl11 Hello out
172.16.11.111 Standby pri 100 ip 172.16.11.115
*Mar 1
00:12:40.279: SB11: Vl11 Hello in 172.16.11.112 Active pri 50 ip
172.16.11.115
*Mar 1 00:12:40.279: SB11: Vl11 Standby: h/Hello
rcvd from lower pri Active router (50/172.16.11.112)
*Mar 1
00:12:41.551: SB11: Vl11 Hello out 172.16.11.111 Standby pri 100 ip
172.16.11.115
*Mar 1 00:12:43.191: SB11: Vl11 Hello in
172.16.11.112 Active pri 50 ip 172.16.11.115
*Mar 1
00:12:43.191: SB11: Vl11 Standby: h/Hello rcvd from lower pri Active router
(50/172.16.11.112)
*Mar 1 00:12:44.539: SB11: Vl11 Hello out
172.16.11.111 Standby pri 100 ip 172.16.11.115
*Mar 1
00:12:46.167: SB11: Vl11 Hello in 172.16.11.112 Active pri 50 ip
172.16.11.115
*Mar 1 00:12:46.167: SB11: Vl11 Standby: h/Hello
rcvd from lower pri Active router (50/172.16.11.112)
*Mar 1
00:12:47.415: SB11: Vl11 Hello out 172.16.11.111 Standby pri 100 ip
172.16.11.115
*Mar 1 00:12:49.119: SB11: Vl11 Hello in
172.16.11.112 Active pri 50 ip 172.16.11.115
*Mar 1
00:12:49.119: SB11: Vl11 Standby: h/Hello rcvd from lower pri Active router
(50/172.16.11.112)
*Mar 1 00:12:50.267: SB11: Vl11 Hello out
172.16.11.111 Standby pri 100 ip 172.16.11.115
Example: HSRP on Preempt Configured Router Coming Up
DSW111
(172.16.11.11) is configured with a priority of 100. This priority is higher
than the priority of the active router DSW112 (172.16.11.112). DSW111 is also
configured with preempt. Only when a router is configured with preempt will
that router with a higher priority transition into the active state. At
time-stamp Mar 1 00:16:43.099, the interface VLAN11 on DSW111 comes up and
transitions into the listen state. At time-stamp Mar 1 00:16:43.295, DSW111
receives a hello message from the active router (DSW112). DSW111 determines
that the active router has a lower priority. At time-stamp Mar 1 00:16:43.295,
DSW111 immediately sends out a coup message, indicating that DSW111 is
transitioning into the active router. DSW112 enters the speak state and
eventually becomes the standby router.
DSW111(config)#interface vlan
11
DSW111(config-if)#no shut
*Mar 1 00:16:41.295: %SYS-5-CONFIG_I: Configured from console
by console
*Mar 1 00:16:43.095: %LINK-3-UPDOWN: Interface
Vlan11, changed state to up
*Mar 1 00:16:43.099: SB: Vl11
Interface up
*Mar 1 00:16:43.099: SB11: Vl11 Init: a/HSRP
enabled
*Mar 1 00:16:43.099: SB11: Vl11 Init ->
Listen
*Mar 1 00:16:43.295: SB11: Vl11 Hello in 172.16.11.112
Active pri 50 ip 172.16.11.115
*Mar 1 00:16:43.295: SB11: Vl11
Active router is 172.16.11.112
*Mar 1 00:16:43.295: SB11: Vl11
Listen: h/Hello rcvd from lower pri Active router
(50/172.16.11.112)
*Mar 1 00:16:43.295: SB11: Vl11 Active
router is local, was 172.16.11.112
*Mar 1 00:16:43.295: SB11:
Vl11 Coup out 172.16.11.111 Listen pri 100 ip
172.16.11.115
*Mar 1 00:16:43.295
*Mar 1
00:16:43.299: %STANDBY-6-STATECHANGE: Vlan11 Group 11 state Listen ->
Active
*Mar 1 00:16:43.299: SB11: Vl11 Hello out 172.16.11.111
Active pri 100 ip 172.16.11.115
*Mar 1 00:16:43.303: SB11:
Vl11 Hello in 172.16.11.112 Speak pri 50 ip 172.16.11.115
*Mar
1 00:16:44.095: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan11, changed
state to up
*Mar 1 00:16:46.187: SB11: Vl11 Hello in
172.16.11.112 Speak pri 50 ip 172.16.11.115
*Mar 1
00:16:46.207: SB11: Vl11 Hello out 172.16.11.111 Active pri 100 ip
172.16.11.115
*Mar 1 00:16:49.095: SB11: Vl11 Hello in
172.16.11.112 Speak pri 50 ip 172.16.11.115
*Mar 1
00:16:49.195: SB11: Vl11 Hello out 172.16.11.111 Active pri 100 ip
172.16.11.115
*Mar 1 00:16:52.079: SB11: Vl11 Hello in
172.16.11.112 Speak pri 50 ip 172.16.11.115
*Mar 1
00:16:52.147: SB11: Vl11 Hello out 172.16.11.111 Active pri 100 ip
172.16.11.115
*Mar 1 00:16:53.303: SB11: Vl11 Hello in
172.16.11.112 Standby pri 50 ip 172.16.11.115
*Mar 1
00:16:53.303: SB11: Vl11 Standby router is 172.16.11.112
*Mar
1 00:16:55.083: SB11: Vl11 Hello out 172.16.11.111 Active pri 100 ip
172.16.11.115
*Mar 1 00:16:56.231: SB11: Vl11 Hello in
172.16.11.112 Standby pri 50 ip 172.16.11.115
*Mar 1
00:16:58.023: SB11: Vl11 Hello out 172.16.11.111 Active pri 100 ip
172.16.11.115
*Mar 1 00:16:59.223: SB11: Vl11 Hello in
172.16.11.112 Standby pri 50 ip 172.16.11.115
*Mar 1
00:17:00.983: SB11: Vl11 Hello out 172.16.11.111 Active pri 100 ip
172.16.11.115
*Mar 1 00:17:02.211: SB11: Vl11 Hello in
172.16.11.112 Standby pri 50 ip 172.16.11.115
*Mar 1
00:17:03.847: SB11: Vl11 Hello out 172.16.11.111 Active pri 100 ip
172.16.11.115