SP: Collaborative Research: Rapid Evolution of Transport Protocols

互联网是一项巨大的工程成就。至少在过去的十年里，它保持了令人兴奋的增长和变化，并发现了广泛的应用，使其成为社会结构的一部分。在底层技术和新应用的驱动下，它肯定会继续发展。这种发展得到了大量和多样化的研究的支持，这些研究经常预测未来的需求。就传输协议而言，我们的重点是，未来将保持新一代流媒体的协议，以非常高的速率稳定的拥塞控制，移动、多宿主和聚合连接，以及通过对等网络和应用层多播进行信息传播-至少。不幸的是，从这类研究的结果转移到全球互联网上是非常困难的，无论这项研究有多有前途。今天，操作系统供应商，而不是研究人员，甚至产品开发人员，通常必须提供新的传输协议。为了适合部署，这些协议必须能够在长期逐步采用的过程中成功地与已安装的运输机进行互操作。这一过程既昂贵又耗时。更隐秘的是，它有一种激励结构，阻碍了试验和早期采用者。归根结底，目前的升级机制可以说是实现许多正在进行的研究工作的好处的限制因素。研究人员建议探索一种新的传输协议演变方法，使实验人员能够快速而轻松地升级传输协议。它将在现实的互联网环境中这样做，而不是那么关心现有的用户群。例如，这将允许网格社区部署针对高速率传输而仔细调优的TCP，或者允许研究拥塞管理器的研究人员准备在大规模和广域范围内对其进行实验。设想的系统将从根本上不同于今天的独立终端系统升级，允许连接的一端通过使用不可信的移动代码来升级另一端。这种“双端”升级模型将使激励结构的平衡向早期采用者倾斜，从而鼓励部署有用的协议。它将允许研究人员和开发人员直接升级传输协议，而不是通过操作系统供应商间接升级，从而鼓励实验。提出者认为，它有可能使目前正在由其他人进行的研究的好处成倍增加。关键的挑战是确定如何在不否定其实际好处的情况下，通过双端升级实现快速发展的直接愿景。这是一项艰巨的任务，因为不可信移动代码的使用以前已经在更一般的活动网络领域进行了探索，但成功有限。然而，他们在该提案的正文中辩称，现在是时候就传输协议部署进行协调研究了。在理解网络协议方面的最新进展(特别是具有ECN随机数的TCP友好性和健壮的拥塞信令)、对安全语言运行时中的共享和终止问题的理解、成熟的语言技术(以安全但类似于C的语言Cyclone的形式)，以及定义明确的简化保护问题的问题域，使得有效使用不可信的移动代码成为现实，尽管具有挑战性。PI在所有这些领域都有专业知识，并建立了研究合作关系。拟议的研究有可能通过真正的倍增效应产生广泛的影响：它直接有助于实现由其他人进行的研究的好处，通过其激励结构鼓励而不是阻止升级。在现实环境中轻松试验新的传输协议将降低研究障碍，帮助更多的研究人员(特别是少数族裔机构)更多地基于他们的想法而竞争，而不是他们能够召集的部署资源的水平。研究人员预计，这项工作将具有很强的教育性，因为学生和研究人员可以安全地进行实验，而不会担心对网络造成不利影响，即使在通用的共享机器上也是如此。真正的部署，也许是解决真正的问题，可以在同学中发生，最终只受到协议的价值和学生宣传它的能力的限制。因此，学生和研究人员将被赋予权力和动力。

The Internet is a tremendous engineering success. It has sustained a heady rate of growth and changeover at least the past decade and has found broad application that has made it part of the fabric of society.Driven by changes in the underlying technology and by new applications, it is certain to continue evolving.Such evolution is supported by a large and diverse body of research that often anticipates future needs.In the case of transport protocols, our focus, the future holds protocols for a new generation of streamingmedia, stable congestion control at very high rates, mobile, multi-homed and aggregate connections, andinformation dissemination via peer-to-peer networks and application-level multicast-at least.Unfortunately, it is very difficult to move from the results of such research to use in the global Internet,no matter how promising the research. Today, operating system vendors, not researchers nor even productdevelopers, must typically provide new transport protocols. To be suitable for deployment, these protocolsmust be able to successfully interoperate with the installed base of transports during the long period ofgradual adoption. This process is costly and time-consuming. More insidiously, it has an incentive structurethat discourages experimentation and early adopters. The bottom line is that current upgrade mechanismsare arguably the limiting factor in realizing the benefits of many ongoing research efforts.The researcherss propose to investigate a new approach to the evolution of transport protocols that will allow experimenters to quickly and easily upgrade transport protocols. It will do so in a realistic Internet setting and with less concern for the installed base. This would allow, for example, the GRID community to deploya TCP carefully tuned for high-rate transfers, or researchers studying the Congestion Manager to readilyexperiment with it at a large scale and across the wide-area. The system envisioned will fundamentallydiffer from today's independent end-system upgrades by allowing one end of a connection to upgrade theother by using untrusted mobile code. This "dual-end" upgrade model will encourage the deployment ofuseful protocols by tipping the balance of the incentive structure in favor of early adopters. It will encourageexperimentation by allowing researchers and developers to upgrade transport protocols directly, rather thanindirectly via operating system vendors. The proposers believe it has the potential to multiply the benefits of research that is currently being undertaken by others.Intellectual Merit. The key challenge is to determine how it is possible to realize the straightforwardvision of rapid evolution via dual-end upgrades without negating its practical benefits. This is a difficulttask, as the use of untrusted mobile code has been previously explored in the much more general domain ofactive networks, with limited success. However, they argue in the body of this proposal that now is the timefor a concerted research effort on transport protocol deployment. Recent advances in the understanding ofnetwork protocols (specifically TCP friendliness and robust congestion signaling with ECN nonces), understanding of the sharing and termination issues in safe-language runtimes, and maturing language technology (in the form of Cyclone, a safe yet C-like language)-plus a well-defined problem domain that simplifies protection issues-have made the effective use of untrusted mobile code a real, though challenging, possi-bility. The PIs have expertise in all of these areas, along with an established research collaboration.Broader Impacts. The proposed research has the potential to achieve a broad impact by a true multipliereffect: it directly helps to realize the benefits of research that is undertaken by others, encouragingrather than discouraging upgrades by virtue of its incentive structure. The ease of experimenting with newtransport protocols in a realistic setting will lower the research barrier, helping a larger pool of researchers (and particularly minority institutions) to compete more on the basis of their ideas and less on the level of deployment resources they are able to muster. The researchers expect there to be a strong educational component of this work, since students as well as researchers can safely experiment without concern for adversely impacting the network, even on generic, shared machines. Real deployment, perhaps solving real problems, can occur among fellow students, and is ultimately limited only by a protocol's value and the students' ability to publicize it. Thus will students, and researchers, be empowered and motivated.