发明名称 Data packet format in HDLC protocol with retransmission of frames having an error.
摘要 <p>A protocol and data packaging format optimized for transmissions over noisy communications links is disclosed. The data packaging format provides a modified High-level Data Link Control (HDLC) control mechanism incorporated into a normal data communication header thus eliminating the requirement for control messages to acknowledge or reject transmissions. An eight bit value is used to encode a toggle bit status for each of eight possible transmit sequence numbers. The eight bit value when used alone, constitutes a null frame indicating data-free feed-back. The null frame is used to confirm receipt of data frames. This eight bit value is also used as the first byte of every data frame. The second byte of the data frame consists of a four-bit logical channel index, a single bit transmit toggle bit and a three-bit transmit sequence number. The second byte of the data frame may be followed by zero or more eight-bit data bytes. When a data frame arrives at a receiver, the bit value of the transmit toggle bit is copied into one of the eight bits of the first byte according to the transmit sequence number. The receiver sends the newly modified first byte back to the sender as part of a data frame transfer or as a null frame to confirm receipt of the data frame. &lt;IMAGE&gt;</p>
申请公布号 EP0494035(A2) 申请公布日期 1992.07.08
申请号 EP19910480178 申请日期 1991.12.06
申请人 INTERNATIONAL BUSINESS MACHINES CORPORATION 发明人 NAGY, MICHAEL E.
分类号 H04L1/18;H04L1/16;H04L29/08 主分类号 H04L1/18
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