Analysis of CGSDS file delivery protocol: immediate NAK mode

We analyze the immediate negative acknowledgment (NAK) mode of the consultative committee for space data systems (CCSDS) file delivery protocol for the single-hop file transfer operation. We propose a timer setting rule that minimizes the expected time taken to transfer a file under the constraint that the throughput efficiency is maximized. Then, we derive the expected file delivery time and compare it with that of the deferred NAK mode. The main contribution is the closed-form expression for evaluating the performance metrics.