LTP for Reliable Data Delivery From Space Station to Ground Station in the Presence of Link Disruption

Designed as the primary transport protocol of delay/disruption-tolerant networking (DTN) in space, Licklider Transmission Protocol (LTP) is expected to provide reliable data delivery service in a challenging networking environment regardless of presence of random link disruptions and/or extremely long propagation delays. The NASA has implemented the use of DTN protocol on the International Space Station for data delivery to the earth ground station. However, there is a lack of a performance evaluation of LTP for its use in the space station communications, especially in presence of link disruption. In this article, a study using a PC-based experimental infrastructure is presented in evaluating the performance of LTP for reliable data delivery from the space station to the ground stations. Realistic experiment results are presented with a focus on the effect of link disruption occurred either over the downlink or over the uplink. The effect of data loss due to channel error is also investigated.