Multicast method and apparatus

A multicast apparatus, comprising:

• a multicast data storing module configured to store multicast data;
• a forwarding path module configured to store a forwarding path corresponding to a multicast forwarding subtree;
• a state control module configured to
• determine whether the multicast forwarding subtree needs to forward data,
• if no data needs to be forwarded, set the multicast forwarding subtree to be in a state of not forwarding the multicast data, and send a stop-forwarding command to a forwarding module;
• if data needs to be forwarded, set the multicast forwarding subtree to be in a state of forwarding the multicast data, and send a forwarding command to a forwarding module;
• and
• the forwarding module configured to perform one of (a) stopping forwarding the multicast data according to the stop-forwarding command from the state control module;
• or (b) forwarding the multicast data from the multicast data storing module according to the forwarding command from the state control module and the forwarding path from the forwarding path module.