Optimize VLAN Broadcast and Multicast Traffic
Broadcast and Multicast (BCMC) traffic from APs, remote APs, or distributions terminating on the same VLAN floods all VLAN member ports. This causes critical bandwidth wastage especially when the APs are connected to L3 cloud where the available bandwidth is limited or expensive. Suppressing the VLAN BCMC traffic to prevent flooding can result in loss of client connectivity.
To effectively prevent flooding of BCMC traffic on all VLAN member ports, use the bcmc-optimizationparameter under the interface vlancommand. This parameter ensures controlled flooding of BCMC traffic without compromising the client connectivity. By default this option is disabled. You must enable this parameter for the controlled flooding of BCMC traffic.
The bcmc-optimization parameter has the following exemptions:
All DHCP traffic will continue to flood VLAN member ports even if the bcmc-optimizationparameter is enabled.
The controllerwill do proxy ARP if the target IP entry exists on the controller. If the target IP does not exist on the controller, ARP requests will be flooded on all VLAN member ports.
You can configure BCMC optimization in CLI and in the WebUI.
In the CLI
(host) (config) #interface vlan 1
(host) (config-subif)#bcmc-optimization
(host) (config-subif)#show interface vlan 1
http://www.arubanetworks.com/techdocs/ArubaOS_60/UserGuide/Network_Parameters.php