Relay unit and frame tracing method

Abstract

In a relay unit for relaying frames between a sending source and a receiving end by transmitting the frames from a transmitting-receiving buffer to the receiving end after the frames received from the sending source have temporarily been stored in the transmitting-receiving buffer, the frames are in the transmitting-receiving buffer, while the storage positions of the frames in the transmitting-receiving buffer are being managed in order of storage. Each time a new frame is stored in the transmitting-receiving buffer after the number of the frames in the transmitting-receiving buffer has reached a predetermined number, the storage area, in which the oldest frame among the frames is stored, is released from the transmitting-receiving buffer. With this arrangement, by contriving how to utilize the transmitting-receiving buffer, tracing a frame can be performed at high speeds, without providing a dedicated storage area for storing trace information and incurring complexity of the process.

1 . An apparatus comprising: 
 a management table managing storage positions of frames in a transmitting-receiving buffer in order of receipt of said frames, registering a storage position of each frame, registering a position of a next-received frame as a next-frame pointer, registering a position corresponding to an oldest frame as a head-frame pointer, and registering a position of a newest frame as a last-frame pointer; and    a control section controlling 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, by referring to said management table.    
   
   
       2 . A method comprising: 
 holding frames in storage areas in a transmitting-receiving buffer,    managing storage positions of said frames in said transmitting-receiving buffer in an order of receipt of said frames; and    releasing the storage area, in which the oldest frame among said frames is stored, from said transmitting-receiving buffer after said frame is relayed, 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,    wherein a predetermined area of the storage area for each said frame is traceably held in said transmitting-receiving buffer when the storage area is released from said transmitting-receiving buffer.