Multicast MAC Address VLAN Port Limit

Specified layer two multicast MAC addresses can be limited to specific ports within a VLAN. You can append or clear ports from the list of ports the multicast MAC address is dynamically learned on or flooded to.

Use the set mac multicast command in any command mode to limit the specified multicast MAC address to specific ports within a VLAN. This command creates a static MAC address that forces frames with a specific multicast destination address to be hardware switched on a the specified VLAN. This command can also be used to flood a unicast MAC address. The command takes a list of ports. The specified port list scopes the flooding to a port set smaller than the egress port set for the VLAN. Multicast frames matching a static MAC address entry are transmitted on each of the specified ports (or all ports if no port is specified) that egresses the VLAN.

Note

A key purpose of the static multicast MAC address feature is to support the multicast version of various NIC-based proprietary load balancing technologies, including Network Load Balancing (NLB). See Network Load Balanced (NLB) Servers Configured for Multicast.

The following example specifies that multicast MAC address 00:a4:01:ff:0e:00:01 be limited to port ge.1.1 on VLAN 100:

System(rw)->set mac multicast 00:a4:01:ff:0e:01 100 ge.1.1
Warning: Unicast address converted to multicast 01-A4-01-FF-0E-01

Unicast MAC addresses can be statically entered into a FID for a single port. This entry can be configured as either permanent or ageable. If ageable, it will age out the same as a dynamically learned MAC address.