Owner's manual

Chapter 17: IGMP Snooping
222 Section II: Advanced Operations
MAC address table from filling up with multicast addresses, leaving no
room for dynamic or static MAC addresses. The range is 1 address to
2048 addresses. The default is 256 multicast addresses.
4. Click Apply.
5. From the Configuration menu, select the Save Config option to
permanently save your changes. (This option is not displayed if there
are no changes to save.)