Alcatel-Lucent 7750 SR-OS, Configuration Manual

Page: 358 / 674

Page 358 7750 SR OS Router Configuration Guide
If master-int-inherit is not enabled, the locally configured message-interval must match the
master’s VRRP advertisement message advertisement interval field value or the message is
discarded.
The no form of the command restores the default operating condition which requires the locally
configured message-interval to match the received VRRP advertisement message advertisement
interval field value.
Default
no master-int-inherit — The virtual router instance does not inherit the master VRRP router’s
advertisement interval timer and uses the locally configured message interval.
message-interval
Syntax message-interval {[ seconds ] [ milliseconds milliseconds ]}
no message-interval
Context config>router>if>vrrp
config>router>if>ipv6>vrrp
Description
This command configures the administrative advertisement message timer used by the master virtual
router instance to send VRRP advertisement messages and to derive the master down timer as
backup.
For an owner virtual router instance, the administrative advertisement timer directly sets the
operational advertisement timer and indirectly sets the master down timer for the virtual router
instance.
Non-owner virtual router instances usage of the message-interval setting is dependent on the state of
the virtual router (master or backup) and the state of the master-int-inherit parameter.
• When a non-owner is operating as master for the virtual router, the configured message-interval
is used as the operational advertisement timer similar to an owner virtual router instance. The
master-int-inherit command has no effect when operating as master.
• When a non-owner is in the backup state with master-int-inherit disabled, the configured mes-
sage-interval value is used to match the incoming VRRP advertisement message advertisement
interval field. If the locally configured message interval does not match the advertisement inter-
val field, the VRRP advertisement is discarded.
• When a non-owner is in the backup state with master-int-inherit enabled, the configured mes-
sage-interval is ignored. The master down timer is indirectly derived from the incoming VRRP
advertisement message advertisement interval field value.
VRRP advertisements messages that are fragmented, contain IP options (IPv4), or contain extension
headers (IPv6) require a longer message interval to be configured.
The in-use value of the message interval is used to derive the master down timer to be used when the
virtual router is operating in backup mode based on the following formula:
(3x (in-use message interval) + skew time)
The skew time portion is used to slow down virtual routers with relatively low priority values when
competing in the master election process.
The command is available in both non-owner and owner vrrp nodal contexts.