At+t Corp.

Bryant Richard Parent

David Hilton Shur

Ram S Ramamurthy

Joseph Golan

Antonio DeSimone

Ashok K Kuthyar

Ram S Ramaurthy

Antonio Desimone

In a multicast capable IP network implemented over an ATM 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. A single special purpose Multicast Address Resolution System (MARS) server is associated with the conference when the conference is established. Each client terminal uses that MARS server, whether on the same or different IP sub-networks, but on a common ATM network, for purposes of mapping the multicast IP addresses used in the conference into a set of unicast ATM endpoint addresses used by the ATM-connected client terminals. Similarly, when a specific conference uses a Multicast Server, a single special purpose Multicast Server is used for all clients on the conference, whether on the same or different IP sub-networks, for purposes of establishing point-to-multipoint ATM connections to the conference endpoints.

Method for managing multicast addresses for transmitting and receiving

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.

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Murray Hill, NJ, United States of America

Bryant Richard Parent