METHOD FOR MANAGING MULTICAST
ADDRESSES FOR TRANSMITTING AND
CONFERENCING INFORMATION ON AN
INTERNET PROTOCOL (IP) NETWORK
 Inventors: Antonio DeSimone; Joseph Golan,
both of Ocean; Ashok K. Kuthyar,
Holmdel; Bryant Richard Parent,
Murray Hill; Ram S. Ramamurthy,
Manalapan; David Hilton Shur,
Middletown, all of N.J.
 Assignee: AT&T Corp., New York, N.Y.
 Appl. No.: 08/848,456  Filed: May 8, 1997
 Int. C I. H04L 12/16
 U.S. CI 370/260; 370/252
 Field of Search 370/259, 260,
370/261, 262, 263, 264, 265, 266, 267, 270, 271, 401, 252; 455/414, 415, 416, 417; 379/202, 212
 References Cited
U.S. PATENT DOCUMENTS
5,674,003 10/1997 Anderson .
5,812,552 9/1998 Arora 370/401
5,835,723 11/1998 Andrews 370/252
5,841,976 11/1998 Tai 370/260
Ahmad, M. et al., "Multicast Communication in Unix 4.2BSD"; Proceedings of the International Conference on Distributed Computing Systems, Denver, Colorado, May
13-17, 1998, vol. C, No. ONE 5, May 13, 1985, pp. 80-87, XP00673844; Institute of Electrical and Electronics Engineers.
Willebeek-LeMair, M. H. et al., "Distributed video conferencing systems"; Computer Communications, vol. 20, No. 3, May 1997, pp. 157-168, XP004081675.
Primary Examiner—Ajit Patel
Assistant Examiner—Ricardo M. Pizarro
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.
26 Claims, 3 Drawing Sheets