The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 29, 2006
Filed:
Sep. 09, 2002
Alexander M. Pass, North Andover, MA (US);
Alexander M. Pass, North Andover, MA (US);
Network Appliance, Inc., Sunnyvale, CA (US);
Abstract
Reliable multicast communication is provided by sending data from a transmitting device to receiving devices as 'bursts' of data transfer units. Each receiving device provides status describing which data transfer units within each previously transmitted burst require retransmission. The transmitting device generates correction data based on this status information by determining a number of subsets of the data transfer units in the burst. Each data transfer unit subset must meet the following condition: if a data transfer unit is included in a given subset, for each receiving device in the group of receiving devices, that data transfer unit must be the only data transfer unit lost by that receiving device and included in that subset. The correction data for a given subset is obtained by applying an exclusive-OR (XOR) operation to all the data transfer units in the subset, and the output is sent to at least one of the receiving devices. Each correction data transfer unit includes the correction data itself, as well as a bit mask describing which data transfer units of the previously transmitted burst are within the subset associated with the correction data. Upon receiving a correction data transfer unit, a receiving device operates to restore a lost or damaged data transfer unit from the previously transmitted burst by applying an XOR operation to correction data in the correction data transfer unit and the correctly received data transfer units in the associated subset.