Calculator system and congestion avoidance method

A calculator system, which is connected to a network including a network switch, recovers, when a data packet is lost on the network, a transfer operation of the lost data packet by a retransmission operation, the calculator system comprising:

• a plurality of calculators;
• software running on the calculators;
• and
• a timing adjusting mechanism present between the calculators and the network,
• wherein the timing adjusting mechanism is configured to:
• calculate a delay time for delaying transmission of a data packet transmitted from the software based on characteristics of the data packet, and
• delay the transmission of the data packet by the calculated delay time,
• wherein the timing adjusting mechanism is configured to;
• record a correspondence relation between the delay time and the number of times of continuous retransmission,
• set a delay time when the number of times of continuous retransmission is the smallest from the correspondence relation as a predetermined value of the delay time, and
• calculate a delay time to be applied to the data packet based on the predetermined value.

A congestion avoidance method for a calculator system, the calculator system including a plurality of calculators and being connected to a network including a network switch, and the calculator system recovering, when a data packet is lost on the network, a transfer operation of the lost data packet by a retransmission operation, the congestion avoidance method comprising:

• a timing adjusting mechanism present between the network and the calculators on which software is running, the timing adjusting mechanism performing:
• acquiring characteristics of a data packet transmitted from the software;
• calculating a delay time for delaying transmission of the data packet based on the characteristics of the data packet;
• and
• delaying the transmission of the data packet by the calculated delay time,
• for a fixed time determined from the characteristics of the data packet in the delay time:
• incrementing the number of times of detection of continuous retransmission to a destination of a data packet having the same content when it is detected that the data packet is continuously retransmitted a first threshold number of times or more;
• increasing a fixed time of a delay time set for transmission to the destination by a set width when it is detected that the number of times of detection of the continuous retransmission is equal to or greater than a second threshold number of times;
• incrementing the number of times of detection of discontinuous retransmission to a destination of a data packet having the same content when it is detected that the data packet is retransmitted only less than a third threshold number of times;
• and
• decreasing a fixed time of a delay time set for transmission to the destination by a set width when it is detected that the number of times of detection of the discontinuous retransmission is equal to or greater than a fourth threshold number of times, thereby automatically adjusting the fixed time according to a state of the network.