Configuration procedure – H3C Technologies H3C S12500 Series Switches User Manual
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The master router of a VRRP group can periodically send gratuitous ARP packets to the hosts on the
local network, so that the hosts can update local ARP entries and avoid using the virtual IP address
of the VRRP group.
If the virtual IP address of the VRRP group is associated with a virtual MAC address, the sender
MAC address in the gratuitous ARP packet takes the virtual MAC address of the virtual router. If the
virtual IP address of the VRRP group is associated with the real MAC address of an interface, the
sender MAC address in the gratuitous ARP packet takes the MAC address of the interface on the
master router in the VRRP group.
•
Update MAC entries of switches in the VLANs having ambiguous VLAN termination configured.
In VRRP configuration, if ambiguous VLAN termination is configured for many VLANs and VRRP
groups, interfaces configured with VLAN termination need to be disabled from transmitting
broadcast/multicast packets and a VRRP control VLAN needs to be configured so that VRRP
advertisements can be transmitted within the control VLAN only. In such cases, you can enable
periodic sending of gratuitous ARP packets containing the VRRP virtual IP address, and the primary
IP address or a manually configured secondary IP address of the sending interface on the
subinterfaces. In this way, when a VRRP failover occurs, switches in the VLANs having ambiguous
VLAN termination configured can use the gratuitous ARP packets to update their corresponding
MAC entries in time.
For more information about VRRP, see High Availability Configuration Guide.
For more information about VLAN termination, see Layer 2—LAN Switching Configuration Guide.
Configuration procedure
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enable the gratuitous ARP
packet learning function.
gratuitous-arp-learning enable
Enabled by default.
3.
Enable the switch to send
gratuitous ARP packets when
receiving ARP requests from
another network segment.
gratuitous-arp-sending enable
Optional.
By default, a switch does not send
gratuitous ARP packets upon
receiving ARP requests from
another network segment.