Patent ID: 7200672

Claim:
A flow control system for avoiding congestion in a packet switching network which is transmitting data packets at a first transmission packet rate, said system comprising: a transmitting node; a receiving node; and a packet switching network coupling said transmitting node with said receiving node, wherein: said transmitting node comprises: a congestion detection unit for detecting a congestion state of said packet switching network; a first control unit for calculating a new transmission packet rate in response to the congestion state detected by said congestion detection unit; a first application which generates data to be transmitted; a transmission unit for forming data packets from the generated data; and a first packet processing unit for transmitting the data packets formed by said transmission unit from said transmitting node to said receiving node through said packet switching network, said receiving node comprises: a second packet processing unit for receiving the data packets transmitted from said transmitting node: a receiving unit for receiving the data packets from said second packet processing unit and generating an acknowledging packet indicating the condition of the received packets; and a second application for using the data packets received by said receiving unit, said second packet processing unit transmits the acknowledging packet to said first packet processing unit through said packet switching network, said first packet processing unit supplies the acknowledging packet to said congestion detection unit; said congestion detection unit detects the congestion state based on the acknowledging packet, when said congestion detection unit detects congestion, said first control unit calculates the new transmission packet rate by decreasing the transmission packet rate and notifies said first application of the calculated new transmission packet rate, and after transmission is ended of the data that is to be transmitted before changing of the transmission packet rate, designates the new transmission packet rate to said transmission unit, and when said congestion detection unit detects no congestion, said first control unit calculates the new transmission rate by increasing the transmission packet rate and notifies said first application of the calculated new transmission packet rate, and after transmission is ended of the data that is to be transmitted before changing of the transmission packet rate, designates the new transmission packet rate to said transmission unit.