Accommodating Network Evolution and Heterogeneity by Improving Network Transparency

Internet的核心设计原则之一是这样一种思想：网络实现一组最小的功能（IP协议）就足够了，这些功能允许网络互操作和任意两个节点进行通信。然而，由于这个原因，许多最近的网络技术（例如无线、长延迟和经常中断的链接）很难集成到互联网中。本项目探讨了两种能够更好地支持异常链接的核心技术：显式路径查询和端到端自适应。Internet对显式路径查询的支持将允许端点了解用于其通信的链接的关键属性。日本早稻田大学和AIST的i-Path系统为这种路径查询机制提供了基础。新的端到端适应机制将允许端点根据通信路径的功能或特性调整其行为。具体来说，该项目正在修改两个端点系统来响应路径查询结果：1)TCP拥塞控制和重传；2)多媒体流应用程序。这项工作预计将展示这样的系统应该如何适应路径属性，如延迟、带宽、损失率、路由器缓冲和网络内压缩支持。这项工作的更广泛的影响来自于显示显式路径查询对于简化向互联网添加新技术至关重要。通过降低支持连接新技术的门槛，这项研究使许多将产生重大社会影响的系统成为可能，例如用于老年人家庭护理的传感器，以及通往欠发达地区的可容忍延迟的连接。

One of the core design principles of the Internet is the idea that it is sufficient for networks to implement a minimal set of functionality (the IP protocol) to allow networks to interoperate and any two nodes to communicate. However, many recent network technologies (e.g. wireless, long-latency and frequently-disrupted links) have been difficult to integrate into the Internet for this reason. This project explores two core techniques that enable better support for unusual links: explicit path queries and end-to-end adaptation. Internet support for explicit path queries would allow end-points to learn key properties of the links used for their communication. The i-Path system from Waseda University and AIST in Japan provides the foundation for this path query mechanism. New end-to-end adaptation mechanisms would allow end-points to adapt their behavior to the capabilities or quirks of the communication path. In particular, the project is modifying two end-point systems to react to path query results: 1) TCP congestion control and retransmission and 2) multimedia streaming applications. This effort is expected to show how such systems should adapt to the path properties, such as latency, bandwidth, loss rate, router buffering and in-network compression support. The broader impact of this work comes from showing that explicit path querying is critical for simplifying the addition of new technologies to the Internet. By lowering the bar for supporting link new technologies, this research enables a number of systems that will have significant social impact, such as sensors for elderly homecare, and delay-tolerant links to underdeveloped regions.