Multicast control method in Ethernet Passive Optical Network

A method for controlling a multicast in an Ethernet Passive Optical Network, comprising steps of:

• A, configuring different identities for a user-end device and its user ports;
• marking a user with a user-end device identity and a user port identity in a central office device and setting a user's multicast authority table according to the user-end device identity and the user port identity;
• B, controlling a user's multicast authority in the central office device according to said multicast authority table;
• sending, by the central office device, a multicast control frame carrying a multicast identity and said user port identity to the user-end device when the central office device determines the user has a multicast authority;
• setting a multicast filter table and a user filter table in the user-end device corresponding to the user according to a content of the multicast control frame, and filtering by the user-end device multicast data and forwarding the filtered multicast data to a user with a multicast authority according to said multicast filter table and user filter table;
• wherein said step B specifically comprises:
• B1, the user-end device receiving at a user port a request message carrying an multicast identity, adding the user-end device identity and said user port identity into the request message and then sending the request message to the central office device;
• B2, the central office device receiving said request message and searching the multicast authority table, when the user marked by the user-end device identity and the user port identity in said request message is found having the multicast authority, returning the multicast control frame carrying said multicast identity and said user port identity to the user-end device;
• B3, after the user-end device receives said multicast control frame, according to said multicast identity and said user port identity carried by the multicast control frame, establishing and maintaining the multicast filter table including said multicast identity, and establishing and maintaining the user filter table including said multicast identity and corresponding user port identity;
• and
• B4, when the user-end device receives multicast data, searching said multicast filter table and then, when an identity of the multicast to which the multicast data belong is recorded in said multicast filter table, searching said user filter table, and forwarding the multicast data to the user port corresponding to the identity of the multicast recorded in the user filter table.