Abstract: A transmission apparatus unitizes a plurality of variable-length frames in units of predetermined size and sorts the unitized frames for each unit into each of a plurality of ports, thereby transmitting the sorted frames. A reception apparatus accumulates received frames in each port and collects the accumulated frames for each unit from each port.

Abstract: In a traffic control apparatus which controls data transmission rates of a plurality of channels, a transmission demand counter counts a transmission demand signal which a transmission demand generator generates at predetermined intervals set for each channel, a priority ranking determination portion determines a transmission priority ranking of each channel based on a value of the transmission demand counter by a round-robin method or other methods, and transmits a highest priority channel designation signal (cell transmission channel No.) which designates a transmission of a highest priority channel and a signal which decrements the transmission demand counter corresponding to the highest priority channel.