TRANSMISSION SYSTEM

PROBLEM TO BE SOLVED: To provide a transmission system capable of attaining flow control even on the occurrence of an invalidated flow control instruction and making communication on the occurrence of a wrong operation by autonomously restoring to a normal operation. SOLUTION: A flow control instruction transmission section 30 has at least either of an ordinary transmission function for transmitting a flow control instruction for carrying out a flow control in a corresponding congestion state and an autonomous transmission function for selecting one congestion state among a plurality of present congestion states by each period and autonomously transmitting a flow control instruction corresponding to the selected congestion state on the occurrence of an event of causing or releasing the congestion at data reception, and preferentially transmits the flow control instruction of the ordinary transmission wherein the congestion is actually produced or released when the timing of the ordinary transmission is coincident with the timing of the autonomous transmission. A flow control instruction reception section 20 receives the flow control instruction to carry out the flow control by stop of data transmission and transmission of data. COPYRIGHT: (C)2005,JPO&NCIPI