Configuring HSRP

Configuring HSRP
To configure HSRP on a Cisco router, use the standby ip ip_address command in interface
configuration mode:
Terry_1#conf t
Terry_1(config)#
Terry_1(config)#int e0
Terry_1(config-if)#standby ?
<0-255> group number
authentication Authentication string
ip Enable hot standby protocol for IP
mac-address Specify virtual MAC address for the virtual router
mac-refresh Refresh MAC cache on switch by periodically sending packet
from virtual mac address
name Name string
preempt Overthrow lower priority designated routers
priority Priority level
timers Hot standby timers
track Priority tracks this interface state
use-bia Hot standby uses interface's burned in address
Terry_1(config-if)#standby ip 172.16.1.254
Terry_1(config)#^Z
Terry_1#
Terry_1#show standby
Ethernet0 - Group 0
Local state is Active, priority 100
Hellotime 3 holdtime 10
Next hello sent in 00:00:00.358
Hot standby IP address is 172.16.1.254 configured
Active router is local
Standby router is unknown expired
Redundancy in Switched Networks 667
Standby virtual mac address is 0000.0c07.ac00
2 state changes, last state change 00:03:34
Terry_1#
Note that if no HSRP group is specified, the default group of 0 is used, resulting in a standby
MAC address of 0000.0c07.ac00 being used.
To configure preemption, use the standby preempt command in interface configuration mode:
Terry_1#conf t
Terry_1(config)#int e0
Terry_1(config-if)#standby preempt ?
delay Wait before preempting
priority Priority level
<cr>
Terry_1(config-if)#standby preempt
Terry_1(config-if)#
Terry_1#
Note the options with this command. The delay option allows you to specify minimum
delay timers prior to a router preempting. The priority option allows you to select which
router is going to become the active router. The default is 100, and the highest priority wins.
To configure interface tracking, use the standby track command in interface configuration
mode:
Terry_1#conf t
Terry_1(config)#int e0
Terry_1(config-if)#standby track ?
Async Async interface
BRI ISDN Basic Rate Interface
BVI Bridge-Group Virtual Interface
Dialer Dialer interface
Ethernet IEEE 802.3
Lex Lex interface
Loopback Loopback interface
Multilink Multilink-group interface
Serial Serial
Tunnel Tunnel interface
Virtual-Template Virtual Template interface
Virtual-TokenRing Virtual TokenRing
Vlan Catalyst Vlans
Terry_1(config-if)#
Terry_1#
668 Chapter 20  Quality of Service (QoS)
Shown next is the configuration for an active HSRP router, with a priority of 105, tracking
interface serial 0, with authentication and modified timers:
Terry_1#show run
Building configuration...
!
[output cut]
!
hostname Terry_1
!
interface Ethernet0
ip address 172.16.1.1 255.255.255.0
no ip redirects
standby timers 1 4 advertise 2
standby priority 105 preempt
standby authentication globalnet
standby ip 172.16.1.254
standby track Serial0
!
interface Serial0
ip address 172.16.2.1 255.255.255.252
!
[output cut]
!
end
The dynamic information on the HSRP group and interface can be seen using the show
standby command:
Terry_1#sho stand
Ethernet0 - Group 0
Local state is Active, priority 105, may preempt
Hellotime 1 holdtime 4 configured hellotime 1 secholdtime 4 sec
advertise 2 secs
Next hello sent in 00:00:00.004
Hot standby IP address is 172.16.1.254 configured
Active router is local
Standby router is 172.16.1.2 expires in 00:00:03
Standby virtual mac address is 0000.0c07.ac00
2 state changes, last state change 00:40:59
Tracking interface states for 1 interface, 0 up:
up Serial0
Terry_1#