STI: Development of Shared-Network Protocols and Strategies for e-VLBI

甚长基线干涉测量法（VLBI）是对宇宙中遥远射电源进行高分辨率成像和精确测量地球在空间中的运动的最强大的技术之一。分散在地球表面的多个射电望远镜同时以高达1gbps的流数据速率记录来自射电源的数据，持续24小时；然后将数据传送到中央处理站点进行相关性分析。由于VLBI实现的信噪比随着观测带宽的增加而增加，因此一直在努力提高捕获的数据速率。现代高速网络的出现提供了以更高的数据速率和更低的成本以电子方式传输VLBI数据的可能性，以最大限度地发挥观测的科学潜力。然而，VLBI数据的电子传输（称为e-VLBI）对高速全球网络的使用提出了特殊的挑战。必须开发新的协议和策略，使这些应用程序成为高效的高带宽“后台”用户，同时不会显著影响其他正常的网络流量。由于许多高速网络，如阿比林，平均负载并不重，这类应用程序有相当大的潜力，可以有效地利用后台容量，以更少的资金促进更好的科学研究。麻省理工学院干草堆天文台与麻省理工学院计算机科学实验室和麻省理工学院林肯实验室合作，建议承担以下任务来实现这一潜力：开发和测试网络协议和算法，利用实时科学仪器应用程序的特殊特性，利用许多网络上大量可用的低优先级带宽。2. 开发一种可以以低成本广泛部署的系统，可以随着算法的改进而轻松更新，并且可以跟踪技术的发展以获得更高的性能。3. 将作品传播到更广泛的社区。

Very-Long-Baseline Interferometry (VLBI) is one of the most powerful techniques available for the high-resolution imaging of distant radio sources in the universe and for making accurate measurements of the motion of the earth in space. Multiple radiotelescopes scattered over the surface of the earth simultaneously record data from a radio source at streaming data rates as high as 1 Gbps for a 24-hour period; the data are then shipped to a central processing site for correlation analysis. Because the signal-to-noise ratio achieved by VLBI increases with the bandwidth of the observations, there has been a continual effort to increase the captured data rate. The advent of modern high-speed networks offers the possibility to transport VLBI data electronically with much higher data rates and lower costs to maximize the scientific potential of the observations. The electronic transmission of VLBI data (dubbed e-VLBI), however, presents a special challenge to the use of high-speed global networks. New protocols and strategies must be developed so that these applications become efficient high-bandwidth 'background' users, while not significantly impacting other normal network traffic. Because many high-speed networks, such as Abilene, are not heavily loaded on an average basis, there is considerable potential for applications of this class to productively use background capacity, promoting better science for fewer dollars. MIT Haystack Observatory, working jointly with the MIT Laboratory for Computer Science and MIT Lincoln Laboratory, proposes to undertake the following tasks to realize this potential: 1. Develop and test network protocols and algorithms that take advantage of the special characteristics of real-time scientific instrumentation applications to utilize low-priority bandwidth that is available in fair abundance on many networks. 2. Develop a system that can be deployed widely at low cost, that can be easily updated as algorithms improve, and that can track technology evolution to gain higher performance over time. 3. Disseminate the work to a broader community.