Patent ID: 7421511
Filing Date: 2008-09-02
Classification: H04L,Y02D

Abstract:
1. A management device connectable to a first device comprising: a processor; a memory; and an interface connectable to the first device, wherein the processor detects congestion of packets on one of a plurality of paths each of which connects the first device and a second device and notifies the first device of the congestion via the interface, wherein each of the packets includes an address of the first device as a source address, an address of the second device as a destination address and a portion of data to be transferred from the first device to the second device, wherein the number of packets transferred on each path of the plurality of paths is set according to a predetermined ratio for said each path, wherein said first device is a storage device which stores data and conducts read or write on said data in response to read or write requests, wherein said second device is a storage device which stores data and conducts read or write on said data in response to read or write requests, wherein said first device upon receipt of a request to write data therein, performs a remote copy operation of the data to be written to said second device using a plurality of packets on the plurality of paths such that portions of the data to be written are transferred by the plurality of packets across the plurality of paths according to predetermined ratios each being calculated for a corresponding one of the paths according to the detected congestion, wherein said predetermined ratio for said each path defines an amount of packets to be allocated on said each path relative to a total amount of packets on all of the paths so that packets on said each path of the plurality of paths are adjusted relative to the packets on each of the other paths such that a total amount of packets across the plurality of paths carries sufficient data equal to a total of the data to be transferred from the first device to the second device, wherein the first device transfers data to the second device using the plurality of paths at the predetermined ratios, wherein the memory stores information on the predetermined ratios and a change rate to be applied to the predetermined ratio of each of the paths, wherein the processor calculates changed predetermined ratios based on the predetermined ratios and the change rate when congestion of one of the plurality of paths has been detected and sends information of the changed predetermined ratios to the first device to let the first device transfer portions of the data to be written to the second device using the plurality of packets across the plurality of paths at the changed predetermined ratios via the interface, and wherein said change rate being a predetermined minimum value each predetermined ratio is to be increased or decreased when changed.