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United States Patent [w]
Wesley et al.
US006104695A [ii] Patent Number:  Date of Patent:
 REPAIR TTL COMPUTATION AND
CORRECTION MECHANISM TO PERFORM
LOCALIZED REPAIRS IN A MULTICAST
DATA DISTRIBUTION SETUP/FRAMEWORK
 Inventors: Joseph S. Wesley, Quincy; Radia J.
Perlman, Acton, both of Mass.;
Stephen A. Hurst, Nashua, N.H.;
Stephen R. Hanna, Bedford, Mass.;
Miriam C. Kadansky, Westford,
Mass.; Philip M. Rosenzweig, Acton,
 Assignee: Sun Microsystems, Inc., Palo Alto,
 Appl. No.: 09/052,201  Filed: Mar. 31, 1998
 Int. CI.7 G01R 31/08; H04H 1/00;
 U.S. CI 370/216; 370/242; 370/312;
 Field of Search 370/390, 216,
370/242, 244, 252, 432, 312; 714/1, 2,
 References Cited
U.S. PATENT DOCUMENTS
5,675,741 10/1997 Aggarwal et al 395/200.12
Log-Based Receiver-Reliable Multicast for Distributed Interactive Simulation by Hugh W. Holbrook, Sandeep K. Singhal, David R. Cheriton, Department of Computer Science, Stanford University, pp. 328-341. A Reliable Multicast Framework for Light-weight Sessions and Application Level Framing by Sally Floyd, Van Jacobson, Steven McCanne of Lawrence Berkeley Laboratory, University of California,Berkeley, CA 94720, Ching-Gung Liu of University of Southern California, Los Angeles, CA 90089, Lixia Zhang of Xerox PARC 3333 Coyote Hill Road, Palo Alto, CA 94304, pp. 342-356.
Multicast Transport Protocols: A Survey and Taxonomy by Katia Obraczka, Information Science Institute, University of Southern California, IEEE Communication Magazine, Jan., 1998, pp. 94-102.
Reliable Multicast Transport Protocol (RMTP), by Sanjoy Paul, Member IEEE, Krishan K. Sabnani, Fellow, IEEE, John C.-H. Lin and Supratik Bhattacharyya, IEEE Apr. 1997, pp. 407-420.
A Reliable Dissemination Protocol for Interactive Collaborative Applications by Rajendra Yavatkar, James Griffioen, and Madhu Sudan, Department of Computer Science, University of Kentucky, Lexington, KY 40506, pp. 1-13.
(List continued on next page.)
Primary Examiner—Ajit Patel
Assistant Examiner—Hanh Nguyen
Attorney, Agent, or Firm—-Weingarten, Schurgin, Gagnebin & Hayes LLP
Determination of a Time To Live ("TTL") hop count for repair data units transmitted from a repair head to a standard destination device in a communications network is facilitated for multicast transmission. The repair head destination device monitors the path between the repair head destination device and the standard destination devices by exchanging messages with the respective standard destination devices. The repair head transmits control messages to each destination device including a dispatched TTL value and an Internet Protocol ("IP") TTL value. If the control message fails to reach one of the standard destination devices, that standard destination device transmits a transmission failure indication to the repair head destination device. In response to the transmission failure indication the TTL value employed for the control message is increased. Following receipt of the control message, the standard destination device calculates the TTL value required to transmit a data unit from the repair head to the standard destination device by subtracting the IP TTL value from the dispatched TTL value. If the calculated TTL difference value is non-zero then an excess-TTL indication is transmitted from the standard destination device to the repair head destination device.
16 Claims, 5 Drawing Sheets
RMTP: A Reliable Multicast Transport Protocol, by John C. Lin, Department of Computer Sciences, Purdue University, West Lafayette, Indiana 47907 and Sanjoy Paul, AT&T Bell Laboratories, Holmdel, New Jersey, 07733, pp. 1-11.
A Reliable Multicst Framework for Light-weight Sessions and Application Level Framing, by Sally Floyd, Van Jacobson, Steven McCanne of Lawrence Berkeley Laboratory, University of California, Los Angeles, CA 90089, and Lixia Zhang, of Xerox PARC, 3333 Coyote Hill Road, Palo Alto, CA 94304, pp. 1-37.