Adaptive Protocol for Worsening Communication Line Conditions

Standard link protocols have been designed for typical long term bit error rates. A degraded line results in service interruption, requiring end-to-end coordination to effect manual recovery. The minimum throughput could be maintained for exchanging the vital housekeeping and link maintenance information by use of an automatic line recovery scheme. An adaptive data link control protocol is designed for this purpose. As a key feature, the real-time throughput monitoring is performed by correlating several variable parameters, such as: block size, transmission speed, overhead ratio, etc.. Within this paper, the adaptive protocol operational procedure is described in great detail using the ADA design language. Analysis for justifying protocol performance is also provided.