Patent ID: 6822967
Filing Date: 2004-11-23
Classification: H04L

Abstract:
A relay unit relaying frames between a sending source and a receiving end by transmitting said frames from a transmitting-receiving buffer to said receiving end after said frames received from said sending source have temporarily been stored in said transmitting-receiving buffer, said relay unit having a trace unit comprising:a management table in which storage positions of said frames in said transmitting-receiving buffer are managed in order of storage, wherein said order of storage is the order of receipt of said frames, and said management table comprises frame management tables corresponding, respectively, to the frames, in which storage positions of the respective frames are registered, a trace management table in which a position of the frame management table corresponding to an oldest frame and a position of the frame management table corresponding to a newest frame are registered as a head-frame pointer and a last-frame pointer, respectively, and in each said frame management table, a position of the frame management table corresponding to a frame stored next to a corresponding frame in said transmitting-receiving buffer is registered as a next-frame pointer; and a control section that controls both storage of each said frame in a storage area for each said frame in said transmitting-receiving buffer, and release of the storage area for each said frame from said transmitting-receiving buffer by referring to said management table, wherein said control section causes said transmitting-receiving buffer to hold said frames and also releases the storage area in which the oldest frame among said frames is stored, from said transmitting-receiving buffer, each time a new frame is stored in said transmitting-receiving buffer after the number of said frames in said transmitting-receiving buffer has reached a predetermined number.