Data transfer apparatus and method using congestion recovery-type and congestion avoidance-type data transfers

A data transfer apparatus in a network system that includes a first computer, a plurality of second computers and a network connecting the first computer and the plurality of second computers with each other, the plurality of second computers performing data transfers to the first computer simultaneously through an identical path on the network in accordance with requests from applications on the plurality of second computers, the data transfer apparatus comprising:

• a congestion detector that detects congestion on the network;
• a first transfer controller that starts a first type of data transfer using an amount of the network and decreases the amount of the network used by the first type of data transfer in accordance with congestion detected by the congestion detector;
• a resource monitor that monitors the first type of data transfer to calculate the amount of the network used by the first type of data transfer;
• an allocation unit that determines an amount of the network to be used by a succeeding second type of data transfer in accordance with the amount of the network used by the first type of data transfer;
• and
• a second transfer controller that starts the succeeding second type of data transfer using the amount of the network determined by the allocation unit, said second transfer controller does not change a transfer rate of the succeeding second type of data transfer based on the congestion detected by the congestion detector.

A data transfer apparatus that performs data transfers among plural computers connected with each other by a network, the data transfer apparatus comprising:

• a congestion detector that detects congestion of the data transfers on the network;
• a first transfer controller that performs data transfers among the computers by controlling an amount of the network used by the data transfers in accordance with the detection of congestion by the congestion detector;
• a resource monitor that monitors an amount of the network used by the data transfers on a path where the data transfers converge;
• and
• a second transfer controller that performs a succeeding data transfer using an amount of the network that is determined in accordance with the amount of the network used by the data transfers determined by said resource monitor said second transfer controller does not chance a transfer rate of the succeeding data transfer based on the detection of congestion by the congestion detector.

A method for performing data transfers between a plurality of computers connected with each other by a network, comprising the steps of:

• detecting congestion on the network;
• performing data transfers among the computers by controlling an amount of the network used by the data transfers in accordance with the detection of congestion;
• monitoring an amount of the network used by the data transfers on a path where the data transfers converge;
• and
• performing a succeeding data transfer using an amount of the network that is determined in accordance with the amount of the network used by the data transfers determined by said monitoring, said succeeding data transfer taking place at a transfer rate that does not change based on the detection of congestion.

A carrier wave encoded to transmit a control program that is readable by a computer performing data transfers over a network, the control program including instructions for causing the computer to execute the steps of:

• detecting congestion on the network;
• performing data transfers among computers connected with each other by the network by controlling an amount of the network used by the data transfers in accordance with the detection of congestion;
• monitoring an amount of the network used by the data transfers on a path where the data transfers converge;
• and
• performing a succeeding data transfer using an amount of the network that is determined in accordance with the amount of the network used by the data transfers determined by said monitoring, said succeeding data transfer taking place at a transfer rate that does not change based on the detection of congestion.