Method for managing multicast addresses for transmitting and receiving

Abstract

In a multicast capable IP network, each client terminal on a multimedia conference, for each media type it transmits, is assigned a multicast IP address and a port number (together known as a socket) on which to transmit packets, wherein each assigned multicast IP address is unique and different than the multicast IP address assigned to any other client for any media type. Each client terminal then selects, for each media type, which clients on the conference it wants to receive packets from. Only packets that are in fact requested by a client are routed over the multicast IP network to the requesting client. When a conference originator establishes the conference, a number of multicast IP addresses are allocated for later assignment to the clients during the conference. As each client joins the conference, it is assigned a multicast IP address from the allocated group for each media type it will transmit. Those assigned addresses are then marked as unavailable for assignment to any other client that subsequently joins the conference. When the original client later exits the conference, its assigned multicast IP address(es) is (are) marked as available for assignment to a later joining client. At the conclusion of the conference, all multicast IP addresses allocated to the conference are marked as available for use in another conference.