Ip Addresses; Message Interval And Master Inheritance - Alcatel-Lucent 7450 Configuration Manual

The priority is also used to determine when to preempt the existing master. If the preempt
mode value is true, VRRP advertisement messages from inferior (lower priority) masters are
discarded, causing the master down timer to expire and the transition to master state.
The priority value also dictates the skew time added to the master timeout period.

IP Addresses

Each virtual router participating in the same VRID should be defined with the same set of IP
addresses. These are the IP addresses being used by hosts on the LAN as gateway addresses.
Multi-netting supports 16 IP addresses on the IP interface, up to 16 addresses can be assigned
to a specific a virtual router instance.

Message Interval and Master Inheritance

Each virtual router is configured with a message interval per VRID within which it
participates. This parameter must be the same for every virtual router on the VRID.
For IPv4, the default advertisement interval is 1 second and can be configured between 100
milliseconds and 255 seconds 900 milliseconds. For IPv6, the default advertisement interval
is 1 second and can be configured between 100 milliseconds and 40 seconds 950
milliseconds.
As specified in the RFC, the advertisement interval field in every received VRRP
advertisement message must match the locally configured advertisement interval. If a
mismatch occurs, depending on the inherit configuration, the current master's advertisement
interval setting can be used to operationally override the locally configured advertisement
interval setting. If the current master changes, the new master setting is used. If the local
virtual router becomes master, the locally configured advertisement interval is enforced.
If a VRRP advertisement message is received with an advertisement interval set to a value
different than the local value and the inherit parameter is disabled, the message is discarded
without processing.
The master virtual router on a VRID uses the advertisement interval to load the advertisement
timer, specifying when to send the next VRRP advertisement message. Each backup virtual
router on a VRID uses the advertisement interval (with the configured local priority) to derive
the master down timer value.
VRRP advertisements messages that are fragmented, or contain IP options (IPv4), or contain
extension headers (IPv6) require a longer message interval to be configured.
Router Configuration Guide
VRRP
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