As the main data transport protocol of delay/disruption-tolerant networking, Licklider transmission protocol (LTP) is developed to provide reliable and highly efficient data delivery over unreliable deep-space and interplanetary communication channels. For reliable data delivery, a checkpoint (CP) segment of LTP is sent, with a timer set (or, simply, CP timer) to check the arrival status of the entire data block at the receiver, and it is retransmitted upon the expiration of the CP timer prior to reception of an acknowledgment. Little work has been seen in analysis of the CP timer length for optimal performance of LTP in energy-efficient, reliable data delivery. In this article, a packet-level analysis of the CP timer length setting is presented for the reliable data delivery of LTP over unreliable deep-space communication channels based on realistic file transfer experiments conducted using a PC-based testbed. It is our intent to find an optimal CP timer setting so that the reliable file delivery in deep space is ensured with a minimum number of retransmission attempts. By this, the energy-efficient, reliable data delivery of LTP can be achieved in deep-space communications.

中文翻译：

---

Licklider传输协议检查点定时器优化设置研究

作为延迟/中断容忍网络的主要数据传输协议，Licklider 传输协议 (LTP) 旨在通过不可靠的深空和星际通信通道提供可靠和高效的数据传输。为了可靠的数据传递，发送 LTP 的检查点 (CP) 段，并设置一个定时器（或简称为 CP 定时器）来检查整个数据块在接收方的到达状态，并在超时时重新发送接收确认之前的 CP 定时器。在分析 CP 定时器长度以实现 LTP 在节能、可靠的数据传输方面的最佳性能方面，几乎没有工作。在本文中，基于使用基于 PC 的测试平台进行的实际文件传输实验，提出了对 CP 定时器长度设置的数据包级分析，用于在不可靠的深空通信信道上可靠地传输 LTP 数据。我们的目的是找到一个最佳的 CP 计时器设置，以便以最少的重传尝试次数确保深空中可靠的文件传递。通过这种方式，可以在深空通信中实现 LTP 的节能、可靠的数据传输。