Data link control improvements for satellite transmission

A protocol is presented for obtaining enhanced performance and efficiency for satellite transmission in point-to-point communication. Attention is focused on procedures for requesting the retransmission of error-containing data frames and selectively acknowledging frames on channels with long propagation times. It is noted that due to propagation times up to 450 kbits of data may be in transit when acknowledgement is broadcast, indicating that the current standard of a modulo 8, 128 octets/frame is insufficient given present transmission rate capabilities. Larger buffers or the ability to request specific frames for errored messages are two techniques for ameliorating the problem. Other methods are modulo 16 and variable length checkpoint response formats. The necessary operational procedures for implementing the new formats are outlined.