Abstract：The Licklider transmission protocol(LTP) is a point-to-point protocol that is mainly used to transmit data between adjacent nodes in space networks. LTP achieves reliability by return acknowledgements and retransmissions. Typical applications have long distances between network nodes which result in large transmission delays. This delay is further multiplied by the acknowledgement and retransmission processes. Thus, the number of round trips(QoRT) needed to successfully transmit an LTP block needs to be investigated. This paper presents an analytical evaluation of the QoRT that gives the distribution function, mean and variance of the QoRT. The results also give more concise upper bounds, lower bounds and approximate means. Simulations verify the theoretical results.
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