Page 357

HSRP

317

If the standby router stops receiving hellos from the active router, it will

then start answering for the virtual IP address, thinking the active router
is down.

Active Router Properties

The first router configured will become the active router. The active router
is the router currently forwarding packets for the virtual router. The standby
router is the primary backup router.

The Priority option set on the router controls which router will be the

active router when the election occurs. The default priority on a router is
100, and the router with the highest priority wins the election. However, if
a router with a lower priority is the active router and a router with a higher
priority joins the group, an election will not occur unless the Preempt option
is set. If the Preempt option is set, then the new router will force an election.
If the new router wins, it becomes the active router. This process is called
a coup.

The router output below shows this process:

RouterB#conf t

RouterB(config)#int ethernet 0

RouterB(config-if)#standby 1 priority 110

RouterB(config-if)#standby 1 preempt

17:44:30: %STANDBY-6-STATECHANGE: Standby: 1: Ethernet0
state Standby -> Active

RouterB(config-if)#^Z

RouterB#sh standby

Ethernet0 - Group 1

Local state is Active, priority 110, may preempt

Hellotime 3 holdtime 10

Next hello sent in 00:00:01.288

Hot standby IP address is 10.1.0.200 configured

Active router is local

Standby router is 10.1.0.1 expires in 00:00:09

Standby virtual mac address is 0000.0c07.ac01

RouterB#

Additional properties can be set to control the virtual address of the

router: the Hello interval, which is 3 seconds by default, and the Hold inter-
val, which is 10 seconds by default. If Router B did not transmit any hellos
for 10 seconds, Router A would become the active router.

www.sybex.com