Certain network applications require multiple hosts to share a multicast MAC address. Instead of flooding all ports in the VLAN with this multicast traffic, you can use Multicast MAC filtering to forward traffic to a configured subset of the ports in the VLAN. This multicast MAC address is not an IP multicast MAC address.
At a minimum, map the multicast MAC address to a set of ports within the VLAN. In addition, if traffic is routed on the local host, you must configure an Address Resolution Protocol (ARP) entry to map the shared unicast IP address to the shared multicast MAC address. You must configure an ARP entry because the hosts can also share a virtual IP address, and packets addressed to the virtual IP address need to reach each host.
Ensure that you limit the number of such configured multicast MAC addresses to a maximum of 100. This number is related to the maximum number of possible VLANs you can configure, because for every multicast MAC filter that you configure the maximum number of configurable VLANs reduces by one. Similarly, configuring large numbers of VLANs reduces the maximum number of configurable multicast MAC filters downward from 100.
Although you can configure addresses starting with 01.00.5E, which are reserved for IP multicast address mapping, do not enable IP multicast with streams that match the configured addresses. This configuration can result in incorrect IP multicast forwarding and incorrect multicast MAC filtering.