| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for controlling data transfer for realizing the high quality and high speed transfer of inter-LAN communication through a wide area network. SOLUTION: An IWU(interworking unit) 122 at a reception side LAN returns a latest reception frame sequence number(RSN) 32 and a latest transfer end frame sequence number(TSN) 33 to a transmission side LAN, and an IWU 121 at the transmission side LAN releases data frames until the returned RSN from its own buffer 61, and decides the number of the next continuous transmission frames by using the TSN, the sequence number of a frame 20 recently transmitted by its own device, and the number of credits. It is desirable that the RSN and the TSN are returned in one response frame. It is desirable that the number of credits at the transmission side is changed from a difference between the RSN and the TSN. Also, the loss of the frame is decided only by the illegality of the sequence of the sequence number of the received data frame at the reception side LAN, and the data frame remaining in the buffer for a fixed time is abandoned, and re-transmitted to an end node at the transmission side LAN. |
