HSRP
Hot Standby Router Protocol is cisco proprietary protocol known as First hop Redundancy Protocol
one router or multi-layer switch that actively forwards traffic out of a subnet which called an active-router. If the active router becomes unavailable the second router can detect the absence of an active router and it becomes the active router which called the standby router (Backup router).
HSRP Operation
Clients configured with default gateway that is neither active or standby configured with, which means there is a virtual gateway ip address that clients point to along with virtual MAC address
Virtual Router which often called phantom router that have the actual gateway ip address clients point to.
How HSRP functions
Hello messages used to elect an active router and to inform the standby router that the active router is still available.
Hello messages sent out every 3 seconds, there is also Holdertime Timer (a time after which the standby router becomes that active router (default of 10 senconds)
HSRP ver 2 Holdtimer can be configured in milliseconds, that is how standby router can determine an active router has gone down.
Active Router Election
The router or multi-layer switch with the highest priority is elected as the active router (default priority is 100)
Tracking option
Allows an HSRP router to monitor a network condition such as interface status, and decrements its priority based on that condition.
Preeampt Option
HSRP's preempt option allows a router that was previously the active router to reclaim its rule active router, if it goes down and comes a backup.
Configuring HSRP
R1(config-if)#stan
R1(config-if)#standby 10 ip 10.1.1.1
R1(config-if)#
*Dec 4 19:35:18.983: %HSRP-5-STATECHANGE: FastEthernet0/1 Grp 10 state Standby -> Active
R2(config-if)#standby 10 ip 10.1.1.1
R2(config-if)#
*Dec 4 20:16:50.203: %HSRP-5-STATECHANGE: FastEthernet0/1 Grp 10 state Speak -> Standby
R2(config-if)#standby 1 ip 10.1.1.1
R2(config-if)#
*Mar 1 00:05:32.695: HSRP: Fa0/1 Grp 1 Disabled -> Init
*Mar 1 00:05:32.695: HSRP: Fa0/1 Grp 1 Redundancy "hsrp-Fa0/1-1" state Disabled -> Init
R2(config-if)#
*Mar 1 00:05:42.699: HSRP: Fa0/1 Grp 1 Active router is 10.1.1.2
*Mar 1 00:05:42.699: HSRP: Fa0/1 Interface up
*Mar 1 00:05:42.699: HSRP: Fa0/1 Starting minimum interface delay (1 secs)
*Mar 1 00:05:43.699: HSRP: Fa0/1 Interface min delay expired
*Mar 1 00:05:43.699: HSRP: Fa0/1 Grp 1 Init: a/HSRP enabled
*Mar 1 00:05:43.699: HSRP: Fa0/1 Grp 1 Init -> Listen
*Mar 1 00:05:43.699: HSRP: Fa0/1 Grp 1 Redundancy "hsrp-Fa0/1-1" state Init -> Backup
*Mar 1 00:05:53.699: HSRP: Fa0/1 Grp 1 Listen: d/Standby timer expired (unknown)
*Mar 1 00:05:53.699: HSRP: Fa0/1 Grp 1 Listen -> Speak
*Mar 1 00:05:53.699: HSRP: Fa0/1 Grp 1 Redundancy "hsrp-Fa0/1-1" state Backup -> Speak
*Mar 1 00:06:03.775: HSRP: Fa0/1 Grp 1 Speak: d/Standby timer expired (unknown)
*Mar 1 00:06:03.775: HSRP: Fa0/1 Grp 1 Standby router is local
*Mar 1 00:06:03.775: HSRP: Fa0/1 Grp 1 Speak -> Standby
*Mar 1 00:06:03.775: HSRP: Fa0/1 Grp 1 Redundancy "hsrp-Fa0/1-1" state Speak -> Standby
R2(config-if)#
Standby Content Help
R2(config-if)#standby ?
<0-255> group number
authentication Authentication
delay HSRP initialisation delay
ip Enable HSRP and set the virtual IP address
mac-address Virtual MAC address
name Redundancy name string
preempt Overthrow lower priority Active routers
priority Priority level
redirects Configure sending of ICMP Redirect messages with an HSRP
virtual IP address as the gateway IP address
timers Hello and hold timers
track Priority tracking
use-bia HSRP uses interface's burned in address
R2(config-if)#standby 1 ?
authentication Authentication
ip Enable HSRP and set the virtual IP address
mac-address Virtual MAC address
name Redundancy name string
preempt Overthrow lower priority Active routers
priority Priority level
timers Hello and hold timers
track Priority tracking
R1#show standby brief
P indicates configured to preempt.
|
Interface Grp Prio P State Active Standby Virtual IP
Fa0/1 1 100 Active local 10.1.1.3 10.1.1.1
R1#
R2#show standby brief
P indicates configured to preempt.
|
Interface Grp Prio P State Active Standby Virtual IP
Fa0/1 1 100 Standby 10.1.1.2 local 10.1.1.1
R2#
R2(config-if)#
*Mar 1 00:39:03.035: HSRP: Fa0/1 Grp 1 Coup in 10.1.1.2 Standby pri 110 vIP 10.1.1.1
*Mar 1 00:39:03.035: HSRP: Fa0/1 Grp 1 Active: j/Coup rcvd from higher pri router (110/10.1.1.2)
*Mar 1 00:39:03.035: HSRP: Fa0/1 Grp 1 Active router is 10.1.1.2, was local
*Mar 1 00:39:03.035: HSRP: Fa0/1 Grp 1 Standby router is unknown, was 10.1.1.2
*Mar 1 00:39:03.039: HSRP: Fa0/1 Grp 1 Active -> Speak
*Mar 1 00:39:03.039: %HSRP-6-STATECHANGE: FastEthernet0/1 Grp 1 state Active -> Speak
R2(config-if)#
*Mar 1 00:39:03.039: HSRP: Fa0/1 Grp 1 Redundancy "hsrp-Fa0/1-1" state Active -> Speak
R2(config-if)#
*Mar 1 00:39:13.035: HSRP: Fa0/1 Grp 1 Speak: d/Standby timer expired (unknown)
*Mar 1 00:39:13.035: HSRP: Fa0/1 Grp 1 Standby router is local
*Mar 1 00:39:13.035: HSRP: Fa0/1 Grp 1 Speak -> Standby
*Mar 1 00:39:13.035: HSRP: Fa0/1 Grp 1 Redundancy "hsrp-Fa0/1-1" state Speak -> Standby
R2(config-if)#
*Mar 1 00:39:26.131: HSRP: Fa0/1 Grp 1 Standby: h/Hello rcvd from lower pri Active router (80/10.1.1.2)
*Mar 1 00:39:26.131: HSRP: Fa0/1 Grp 1 Active router is local, was 10.1.1.2
*Mar 1 00:39:26.131: HSRP: Fa0/1 Grp 1 Standby router is unknown, was local
*Mar 1 00:39:26.135: HSRP: Fa0/1 Grp 1 Coup out 10.1.1.3 Standby pri 100 vIP 10.1.1.1
*Mar 1 00:39:26.135: HSRP: Fa0/1 Grp 1 Standby -> Active
*Mar 1 00:39:26.135: %HSRP-6-STATECHANGE: FastEthernet0/1 Grp 1 state Standby -> Active
R2(config-if)#
*Mar 1 00:39:26.135: HSRP: Fa0/1 Grp 1 Redundancy "hsrp-Fa0/1-1" state Standby -> Active
*Mar 1 00:39:26.243: HSRP: Fa0/1 Grp 1 Resign in 10.1.1.2 Speak pri 80 vIP 10.1.1.1
*Mar 1 00:39:26.243: HSRP: Fa0/1 Grp 1 Active: i/Resign rcvd (80/10.1.1.2)
*Mar 1 00:39:26.243: HSRP: Fa0/1 Grp 1 Coup out 10.1.1.3 Active pri 100 vIP 10.1.1.1
R2(config-if)#
*Mar 1 00:39:29.247: HSRP: Fa0/1 Grp 1 Redundancy group hsrp-Fa0/1-1 state Active -> Active
R2(config-if)#
*Mar 1 00:39:32.247: HSRP: Fa0/1 Grp 1 Redundancy group hsrp-Fa0/1-1 state Active -> Active
R2(config-if)#
*Mar 1 00:39:37.895: HSRP: Fa0/1 Grp 1 Standby router is 10.1.1.2
R1#show standby
FastEthernet0/1 - Group 1
State is Active
14 state changes, last state change 00:00:41
Virtual IP address is 10.1.1.1
Active virtual MAC address is 0000.0c07.ac01
Cisco Vender Code HSRP Ver 1.0 Group#<0-255> group number
0000.0c9f.f001
Cisco Vender Code HSRP Ver 2.0 Group# <0-4095> group number
Local virtual MAC address is 0000.0c07.ac01 (default)
Hello time 3 sec, hold time 10 sec
Next hello sent in 0.468 secs
Preemption enabled
Active router is local
Standby router is 10.1.1.3, priority 100 (expires in 9.804 sec)
Priority 110 (configured 110)
Track interface FastEthernet0/0 state Up decrement 30
IP redundancy name is "hsrp-Fa0/1-1" (default)
R2#show ip arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 10.1.1.3 - c002.1640.0001 ARPA FastEthernet0/1
Internet 10.1.1.1 - 0000.0c07.ac01 ARPA FastEthernet0/1
Internet 192.168.14.2 0 0050.56e8.e3c1 ARPA FastEthernet0/0
Internet 10.1.1.100 44 0050.7966.6800 ARPA FastEthernet0/1
Internet 192.168.14.254 32 0050.56fd.eee2 ARPA FastEthernet0/0
Internet 192.168.14.141 - c002.1640.0000 ARPA FastEthernet0/0
Hot Standby Router Protocol is cisco proprietary protocol known as First hop Redundancy Protocol
one router or multi-layer switch that actively forwards traffic out of a subnet which called an active-router. If the active router becomes unavailable the second router can detect the absence of an active router and it becomes the active router which called the standby router (Backup router).
HSRP Operation
Clients configured with default gateway that is neither active or standby configured with, which means there is a virtual gateway ip address that clients point to along with virtual MAC address
Virtual Router which often called phantom router that have the actual gateway ip address clients point to.
How HSRP functions
Hello messages used to elect an active router and to inform the standby router that the active router is still available.
Hello messages sent out every 3 seconds, there is also Holdertime Timer (a time after which the standby router becomes that active router (default of 10 senconds)
HSRP ver 2 Holdtimer can be configured in milliseconds, that is how standby router can determine an active router has gone down.
Active Router Election
The router or multi-layer switch with the highest priority is elected as the active router (default priority is 100)
Tracking option
Allows an HSRP router to monitor a network condition such as interface status, and decrements its priority based on that condition.
Preeampt Option
HSRP's preempt option allows a router that was previously the active router to reclaim its rule active router, if it goes down and comes a backup.
Configuring HSRP
R1(config-if)#stan
R1(config-if)#standby 10 ip 10.1.1.1
R1(config-if)#
*Dec 4 19:35:18.983: %HSRP-5-STATECHANGE: FastEthernet0/1 Grp 10 state Standby -> Active
R2(config-if)#standby 10 ip 10.1.1.1
R2(config-if)#
*Dec 4 20:16:50.203: %HSRP-5-STATECHANGE: FastEthernet0/1 Grp 10 state Speak -> Standby
R2(config-if)#standby 1 ip 10.1.1.1
R2(config-if)#
*Mar 1 00:05:32.695: HSRP: Fa0/1 Grp 1 Disabled -> Init
*Mar 1 00:05:32.695: HSRP: Fa0/1 Grp 1 Redundancy "hsrp-Fa0/1-1" state Disabled -> Init
R2(config-if)#
*Mar 1 00:05:42.699: HSRP: Fa0/1 Grp 1 Active router is 10.1.1.2
*Mar 1 00:05:42.699: HSRP: Fa0/1 Interface up
*Mar 1 00:05:42.699: HSRP: Fa0/1 Starting minimum interface delay (1 secs)
*Mar 1 00:05:43.699: HSRP: Fa0/1 Interface min delay expired
*Mar 1 00:05:43.699: HSRP: Fa0/1 Grp 1 Init: a/HSRP enabled
*Mar 1 00:05:43.699: HSRP: Fa0/1 Grp 1 Init -> Listen
*Mar 1 00:05:43.699: HSRP: Fa0/1 Grp 1 Redundancy "hsrp-Fa0/1-1" state Init -> Backup
*Mar 1 00:05:53.699: HSRP: Fa0/1 Grp 1 Listen: d/Standby timer expired (unknown)
*Mar 1 00:05:53.699: HSRP: Fa0/1 Grp 1 Listen -> Speak
*Mar 1 00:05:53.699: HSRP: Fa0/1 Grp 1 Redundancy "hsrp-Fa0/1-1" state Backup -> Speak
*Mar 1 00:06:03.775: HSRP: Fa0/1 Grp 1 Speak: d/Standby timer expired (unknown)
*Mar 1 00:06:03.775: HSRP: Fa0/1 Grp 1 Standby router is local
*Mar 1 00:06:03.775: HSRP: Fa0/1 Grp 1 Speak -> Standby
*Mar 1 00:06:03.775: HSRP: Fa0/1 Grp 1 Redundancy "hsrp-Fa0/1-1" state Speak -> Standby
R2(config-if)#
Standby Content Help
R2(config-if)#standby ?
<0-255> group number
authentication Authentication
delay HSRP initialisation delay
ip Enable HSRP and set the virtual IP address
mac-address Virtual MAC address
name Redundancy name string
preempt Overthrow lower priority Active routers
priority Priority level
redirects Configure sending of ICMP Redirect messages with an HSRP
virtual IP address as the gateway IP address
timers Hello and hold timers
track Priority tracking
use-bia HSRP uses interface's burned in address
R2(config-if)#standby 1 ?
authentication Authentication
ip Enable HSRP and set the virtual IP address
mac-address Virtual MAC address
name Redundancy name string
preempt Overthrow lower priority Active routers
priority Priority level
timers Hello and hold timers
track Priority tracking
R1#show standby brief
P indicates configured to preempt.
|
Interface Grp Prio P State Active Standby Virtual IP
Fa0/1 1 100 Active local 10.1.1.3 10.1.1.1
R1#
R2#show standby brief
P indicates configured to preempt.
|
Interface Grp Prio P State Active Standby Virtual IP
Fa0/1 1 100 Standby 10.1.1.2 local 10.1.1.1
R2#
R2(config-if)#
*Mar 1 00:39:03.035: HSRP: Fa0/1 Grp 1 Coup in 10.1.1.2 Standby pri 110 vIP 10.1.1.1
*Mar 1 00:39:03.035: HSRP: Fa0/1 Grp 1 Active: j/Coup rcvd from higher pri router (110/10.1.1.2)
*Mar 1 00:39:03.035: HSRP: Fa0/1 Grp 1 Active router is 10.1.1.2, was local
*Mar 1 00:39:03.035: HSRP: Fa0/1 Grp 1 Standby router is unknown, was 10.1.1.2
*Mar 1 00:39:03.039: HSRP: Fa0/1 Grp 1 Active -> Speak
*Mar 1 00:39:03.039: %HSRP-6-STATECHANGE: FastEthernet0/1 Grp 1 state Active -> Speak
R2(config-if)#
*Mar 1 00:39:03.039: HSRP: Fa0/1 Grp 1 Redundancy "hsrp-Fa0/1-1" state Active -> Speak
R2(config-if)#
*Mar 1 00:39:13.035: HSRP: Fa0/1 Grp 1 Speak: d/Standby timer expired (unknown)
*Mar 1 00:39:13.035: HSRP: Fa0/1 Grp 1 Standby router is local
*Mar 1 00:39:13.035: HSRP: Fa0/1 Grp 1 Speak -> Standby
*Mar 1 00:39:13.035: HSRP: Fa0/1 Grp 1 Redundancy "hsrp-Fa0/1-1" state Speak -> Standby
R2(config-if)#
*Mar 1 00:39:26.131: HSRP: Fa0/1 Grp 1 Standby: h/Hello rcvd from lower pri Active router (80/10.1.1.2)
*Mar 1 00:39:26.131: HSRP: Fa0/1 Grp 1 Active router is local, was 10.1.1.2
*Mar 1 00:39:26.131: HSRP: Fa0/1 Grp 1 Standby router is unknown, was local
*Mar 1 00:39:26.135: HSRP: Fa0/1 Grp 1 Coup out 10.1.1.3 Standby pri 100 vIP 10.1.1.1
*Mar 1 00:39:26.135: HSRP: Fa0/1 Grp 1 Standby -> Active
*Mar 1 00:39:26.135: %HSRP-6-STATECHANGE: FastEthernet0/1 Grp 1 state Standby -> Active
R2(config-if)#
*Mar 1 00:39:26.135: HSRP: Fa0/1 Grp 1 Redundancy "hsrp-Fa0/1-1" state Standby -> Active
*Mar 1 00:39:26.243: HSRP: Fa0/1 Grp 1 Resign in 10.1.1.2 Speak pri 80 vIP 10.1.1.1
*Mar 1 00:39:26.243: HSRP: Fa0/1 Grp 1 Active: i/Resign rcvd (80/10.1.1.2)
*Mar 1 00:39:26.243: HSRP: Fa0/1 Grp 1 Coup out 10.1.1.3 Active pri 100 vIP 10.1.1.1
R2(config-if)#
*Mar 1 00:39:29.247: HSRP: Fa0/1 Grp 1 Redundancy group hsrp-Fa0/1-1 state Active -> Active
R2(config-if)#
*Mar 1 00:39:32.247: HSRP: Fa0/1 Grp 1 Redundancy group hsrp-Fa0/1-1 state Active -> Active
R2(config-if)#
*Mar 1 00:39:37.895: HSRP: Fa0/1 Grp 1 Standby router is 10.1.1.2
R1#show standby
FastEthernet0/1 - Group 1
State is Active
14 state changes, last state change 00:00:41
Virtual IP address is 10.1.1.1
Active virtual MAC address is 0000.0c07.ac01
Cisco Vender Code HSRP Ver 1.0 Group#<0-255> group number
0000.0c9f.f001
Cisco Vender Code HSRP Ver 2.0 Group# <0-4095> group number
Local virtual MAC address is 0000.0c07.ac01 (default)
Hello time 3 sec, hold time 10 sec
Next hello sent in 0.468 secs
Preemption enabled
Active router is local
Standby router is 10.1.1.3, priority 100 (expires in 9.804 sec)
Priority 110 (configured 110)
Track interface FastEthernet0/0 state Up decrement 30
IP redundancy name is "hsrp-Fa0/1-1" (default)
R2#show ip arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 10.1.1.3 - c002.1640.0001 ARPA FastEthernet0/1
Internet 10.1.1.1 - 0000.0c07.ac01 ARPA FastEthernet0/1
Internet 192.168.14.2 0 0050.56e8.e3c1 ARPA FastEthernet0/0
Internet 10.1.1.100 44 0050.7966.6800 ARPA FastEthernet0/1
Internet 192.168.14.254 32 0050.56fd.eee2 ARPA FastEthernet0/0
Internet 192.168.14.141 - c002.1640.0000 ARPA FastEthernet0/0
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