The Crossbeam X-Series chassis implements gratuitous ARPs to support two different redundancy features:
An IP address configured in the VRRP context will move from one chassis to another upon VRRP failover. In order to facilitate this change the master VAP sends a gratuitous ARP on each circuit that has a VRRP IP address attached to it.
In addition to gratuitous ARPs triggered by a failover, Crossbeam also broadcasts gratuitous ARPs every 30 seconds on each VRRP-enabled circuit. Periodic ARP announcements are required in some Layer 2 environments. The default interval can be adjusted in /crossbeam/etc/cbsvapcfgd.cf
on VAPs:#Periodic gratuitous arps interval
# default is 30
To make the change, you need to rsh to each VAP, edit the file /crossbeam/etc/cbsvapcfgd.cf
and restart the cbsvapcfgd
2) Redundant Interfaces
This feature allows you to specify the backup for a physical interface. When the backup interface assumes the role of the failed port, it sends a gratuitous ARP request to inform attached Layer 2 or Layer 3 devices about the interface change. Based on the parameter mac-usage
(master or active) either Layer 2 or Layer 3 devices need to be updated about the interface change.