Patent ID: 7474669

Claim:
A broadband access server for replicating a multicast packet from a content server, distributing the replicated packet to terminals, and sending accounting information to an accounting server for providing an accounting, the broadband access server comprising: a communication processing block for communicating with the accounting server; a counter for counting either or both of the number of bytes and the number of packets of a distributed content at each multicast group address; and a user management table for storing a multicast session identifier containing a user identifier and a multicast group address, in correspondence with the user identifier, wherein the broadband access server establishes a session with a terminal, wherein when message requesting membership in a multicast group is received through the established session, wherein the message contains a user identifier and a multicast group address, and wherein the broadband access server: (a) stores a multicast session identifier based on the user identifier and the multicast group address of the message, in correspondence with the user identifier in the user management table; (b) obtains either or both of the number of bytes and the number of packets corresponding to multicast group address of the message from the counter; and (c) sends a message requesting start of multicast accounting through the communication processing block to the accounting server corresponding to the multicast group address, the message requesting start of multicast accounting containing either or both of the number of bytes and the number of packets and a multicast session identifier; and wherein when a fact that the terminal leaves the multicast group is detected, the broadband access server: (d) obtains a multicast session identifier corresponding to the user identifier of the leaved terminal from the user management table; (e) obtains either or both of the number of bytes and the number of packets corresponding to the multicast group address related to the terminal, from the counter; and (f) sends a message requesting stop of multicast accounting through the communication processing block to the accounting server corresponding to the multicast group address, the message requesting stop of multicast accounting containing either or both of the number of bytes and the number of packets and the multicast session identifier which are obtained, wherein the accounting server obtains either or both of the number of distributed bytes and the number of distributed packets from when the terminal joins the multicast group until when the terminal leaves the multicast group, and charges each user and each multicast group by either or both of the number of distributed bytes and the number of distributed packets, or charges each user and each multicast group by a bit rate depending on either or both of the number of distributed bytes and the number of distributed packets.