HP MSR Series Configuration Manual page 30

By default, an ambiguous termination-enabled Layer 3 subinterface drops broadcast and multicast
packets that it receives. You can enable the interface to transmit broadcast packets and multicast packets
as needed. The packets are transmitted within all VLANs whose VLAN packets are configured to be
terminated by the subinterface.
Figure 14 VRRP control VLAN
As shown in
Layer 3 Ethernet subinterfaces on routers. To allow the master to regularly send VRRP advertisements in
multicast to the backups, enable the VLAN termination-enabled subinterfaces to transmit broadcast
packets and multicast packets. Then, the master can send VRRP advertisements within all VLANs whose
VLAN packets are configured to be terminated by the subinterfaces. If ambiguous VLAN termination is
configured on the Layer 3 Ethernet subinterfaces for a large range of VLANs, the VRRP advertisements
might overload the subinterfaces. This adversely affects the performance of the routers.
To solve this problem, perform the following tasks:
• Disable the VLAN termination-enabled subinterfaces from transmitting broadcast packets and
multicast packets.
Configure a VRRP control VLAN to allow the master to send VRRP advertisements only within the
•
control VLAN.
VRRP control VLANs include the following categories:
VLANs with a single VLAN tag—Specified for ambiguous Dot1q termination-enabled
•
subinterfaces.
VLANs with both inner and outer VLAN tags—Specified for ambiguous QinQ termination-enabled
•
subinterfaces.
For more information about VLAN termination, see Layer 2—LAN Switching Configuration Guide.
Configuration guidelines
When VRRP is operating in load balancing mode, you cannot specify the VRRP control VLAN.
•
After you specify a VRRP control VLAN, HP recommends that you configure the arp
•
send-gratuitous-arp command on the routers in the VRRP group. This command enables the routers
to periodically send gratuitous ARP packets. The devices in the VLAN terminated ambiguously can
then update MAC address entries after a master switchover. For more information about the arp
send-gratuitous-arp command, see Layer 3—IP Services Command Reference.
Figure 14, ambiguous VLAN termination is configured for VLAN 10 and VLAN 20 on the
25