dead-interval
The default dead interval is internally derived from the hello interval. It is equal to 3 times the hello interval plus the skew time, where the skew time is equal to (256 minus the priority) divided by 256.
- msec interval
- Sets the interval, in milliseconds, for which a VRRP backup router waits for a hello message from the VRRP master router before determining that the master is offline. Valid values range from 100 through 84000. The default value is 1000. VRRP-E does not support the dead interval in milliseconds.
VRID interface configuration mode
By default, the dead interval is internally derived from the hello interval. It is
equal to 3 times the hello interval plus the skew time, where the skew time is equal
to (256 minus the priority) divided by 256. Generally, if you change the hello interval
on the VRRP master device using the
hello-interval command, you should also change the dead interval on the VRRP backup devices using
the
dead-interval command.
A VRRP master router periodically sends hello messages to the backup routers. The backup routers use the hello messages as verification that the master is still online. If the backup routers stop receiving the hello messages for the period of time specified by the dead interval, the backup routers determine that the master router is offline. At that point, the backup router with the highest priority becomes the new master router.
The
dead-interval command is configured only on VRRP backup routers and is supported by VRRP and VRRP-E.
The
no form resets the dead interval to its default value of 1000 milliseconds (1 second).
The following example sets a waiting period of 25000 milliseconds before a VRRP backup router determines that a VRRP master router is offline.
device# configure terminal device(config)# router vrrp device(config)# interface ethernet 1/1/6 device(config-if-e1000-1/1/6)# ip address 10.53.5.1/24 device(config-if-e1000-1/1/6)# ip vrrp vrid 1 device(config-if-e1000-1/1/6-vrid-1)# backup priority 40 track-priority 10 device(config-if-e1000-1/1/6-vrid-1)# ip-address 10.53.5.99 device(config-if-e1000-1/1/6-vrid-1)# dead-interval msec 25000 device(config-if-e1000-1/1/6-vrid-1)# activate
The following example sets a waiting period of 25 seconds before a VRRP-E backup router determines that a VRRP master router is offline.
device# configure terminal device(config)# router vrrp-extended device(config-vrrpe-router)# interface ethernet 1/1/5 device(conf-if-e1000-1/1/5)# ip address 10.53.5.3/24 device(conf-if-e1000-1/1/5)# ip vrrp-extended vrid 2 device(conf-if-e1000-1/1/5-vrid-2)# backup priority 50 track-priority 10 device(conf-if-e1000-1/1/5-vrid-2)# ip-address 10.53.5.1 device(conf-if-e1000-1/1/5-vrid-2)# dead-interval 25 device(conf-if-e1000-1/1/5-vrid-2)# activate