A read-create integer specifying the ACL number, 0 or in the range 2000-2999, used to restrict which multicast groups a port is allowed to join. By referencing an access control list, this lets an admin enforce a multicast group policy per port, permitting or denying specific multicast addresses independent of the numeric join-count limit. An admin might set this to ACL 2010, previously configured to permit only a specific range of IPTV channel addresses, restricting that port to those channels.