Vrrp Message Authentication; Virtual Mac Address; Vrrp Advertisement Message Ip Address List Verification - Alcatel-Lucent 7705 Configuration Manual

If preempt mode is true, the advertised priority from the incoming VRRP advertisement
message from the current master is compared to the local configured priority. If the local
priority is higher, the received VRRP advertisement message is discarded. This results in the
eventual expiration of the master down timer, causing the backup router to transition to the
master state. If the received priority is equal to the local priority, the message is not discarded
and the current master is not replaced. The received primary IP address is not part of the
decision to preempt and is not used as a tie breaker if the received and local priorities are
equal.
If preempt is disabled, the virtual router only becomes master if the master down timer
expires before a VRRP advertisement message is received from another virtual router.

VRRP Message Authentication

VRRP message authentication uses a simple text password authentication key to generate
master VRRP advertisement messages and validate received VRRP advertisement messages.
If the authentication-key command is re-executed with a different password key
defined, the new key will be used immediately. If a no authentication-key command
is executed, the password authentication key is restored to the default value. The
authentication-key command may be executed at any time.

Virtual MAC Address

The MAC address can be used instead of an IP address in ARP responses if the virtual router
instance is master. The MAC address configuration must be the same for all virtual routers
with the same VRID or the result is indeterminate connectivity by the attached IP hosts. All
VRRP advertisement messages are transmitted with the IEEE address as the source MAC
address.

VRRP Advertisement Message IP Address List Verification

VRRP messages contain an IP address count field that indicates the number of IP addresses
listed in the sequential IP address fields at the end of the message. The 7705 SAR
implementation always logs mismatching events. The decision on where and whether to
forward the generated messages depends on the configuration of the event manager. The log
message is generated by network management and is not the same as the VRRP message.
7705 SAR OS Router Configuration Guide
VRRP
219