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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter23 Configuring HSRP
Configuring HSRP
Use the no standby [group-number] priority priority [preempt [delay delay]] and no standby
[group-number] [priority priority] preempt [delay delay] interface configuration commands to restore
default priority, preempt, and delay values.
Use the no standby [group-number] track type number [interface-priority] interface configuration
command to remove the tracking.
This activates Gigabit Ethernet interface 0/1, sets an IP ad dre ss an d a p rior ity of 120 (hi ghe r th an t he
default value), and waits for 300 seconds (5 minutes) before attempting to become the active router:
Switch# configure terminal
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# standby ip 172.19.108.254
Switch(config-if)# standby priority 120 preempt delay 300
Switch(config-if)# end
Switch#
Configuring HSRP Authentication and Timers
You can optionally configure an HSRP authentication string or change the hello-time interval and
holdtime.
When configuring these attributes, follow these guidelines:
•The authentication string is sent unencrypted in all HSRP messages. You must configure the same
authentication string on all routers and access servers on a cable to ensure interoperation.
Authentication mismatch prevents a device from learning the designate d Hot Standby IP address and
timer values from other routers configured with HSRP.
•Routers or access servers on which standby timer values are not con figur ed ca n le arn tim er v alue s
from the active or standby router. The timers configured on an act ive ro uter a lw ays ov erri de a ny
other timer settings.
•All routers in a Hot Standby group should use the same timer values. Normally, the holdtime is
greater than or equal to 3 times the hellotime.
Beginning in privileged EXEC mode, use one or more of the se st eps to conf igur e HS RP pri ority
characteristics on an interface:
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 interface interface-id Enter interface configuration mode, and enter the HSRP
interface on which you want to set authentication.
Step3 standby [group-number] authentication string (Optional) authentication string—Enter a string to be carr ied in
all HSRP messages. The authentication string can be up to eight
characters in length; the default string is cisco.
(Optional) group-number—The group number to which the
command applies.