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As one of the most important convergence layer (CL) protocol for delay/disruption-tolerant networking (DTN), Licklider transmission protocol (LTP) is designed for deep space communications, but it has rarely been considered for near earth applications. In this paper, LTP is proposed instead of TCP as CL with Bundle protocol (BP) for future application in GEO-relayed space networks (GRSN). Analytical models are built to estimate the file delivery time of LTP in GRSN. Experiments are also conducted on our computer based testbed in emulation of the basic scenarios during data transmission from LEO satellite to a ground station in GRSN. The results show that in transmission efficiency BP with LTPCL outperforms other protocols, such as BP with TCPCL, direct terrestrial TCP (TCP Cubic) and TCP variants (TCP Hybla) for space segments in most scenarios. It could be envisioned that DTN with LTPCL for space segment is currently the best choice for future GEO-relayed space internetworking. Moreover, performance of two different networking schemes,i.e. the on-board DTN routers and the bent-pipe relays are compared. It is observed that bent-pipe relays outperform the on-board DTN routers scheme when the channel condition is good, while the on-board DTN routers scheme performs better with high data loss ratio. [ABSTRACT FROM AUTHOR]

Delay/disruption tolerant networking (DTN) was proposed as a networking architecture for reliable data delivery in space vehicle communications despite long propagation delays and/or lengthy link disruptions. As one of the main data transport protocols of DTN, Licklider transmission protocol (LTP) was proposed by the NASA for reliable data delivery in challenging space environments in which the existing transport protocols of DTN, TCP, and UDP do not perform effectively. Pair-wise comparisons among LTP, TCP, and UDP running in the DTN stack have previously been done using statistical methods; evaluation results and performance analysis are available in the existing LTP research literature. However, there is as yet no solid analytical model of LTP performance in the presence of link disruptions. In this paper, we present an analytical method to predict transmission performance of LTP for reliable file delivery in space vehicle communications with focus on the expected file delivery delay (or latency) over space channels characterized by random link disruptions. Realistic file-transmission experiments using a PC-based infrastructure are presented to validate the analytical models. The analysis and study results presented in this paper are expected to be useful in understanding the impact of transmission conditions and configurations, on the efficiency of LTP when deployed for reliable data delivery in space missions using communication links that are subject to frequent and random interruptions. [ABSTRACT FROM AUTHOR]