Analysis of command operation procedures (COPs) for reliable data transfer in the European Space Data Network

Command operation procedures (COPs) are protocols operating in the transfer layer of the telecommand and telemetry architectures designed by the International Consultative Committee for Space Data Systems. The authors present an evaluation of virtual frame transmission times, throughput efficiency, buffer occupancy, and waiting times for the COP-2. COP-2 represents an ARQ-type (automatic repeat request) protocol with checkpointing that is comparable to the checkpoint mode protocol. A discrete two-class priority service model with random server interruptions is considered. The analysis is based on the concepts of level crossing analysis as defined in J.W. Cohen (1977) and J.G. Shanthikumar (1981). The results of this work will be used by the European Space Agency as design guidelines for the European Data Network