Resource Controlled Active Network Elements (RCANE)

活动网络的高级应用程序需要支持健壮的可配置服务质量（QoS），还需要防止或减轻复杂的“拒绝服务”攻击。主动网络尚未解决的一个主要问题是将应用需求映射到分布式资源复用策略中。由于这个问题也困扰着互联网社区（即IP电话、RSVP等），因此解决方案将对活动网络以外的网络社区产生广泛而直接的影响。Penn/Bellcore SwitchWare活动网络项目使用编程语言限制来平衡灵活性、安全性、可用性和性能。与操作系统强制的内存保护相比，编程语言方法可以被视为限制程序可以生成的地址。这种方法的优点是，一些限制可以在编译时执行一次，而不是在运行时重复执行。此外，诸如ML之类的编程语言技术提供了强大的类型检查，这是自动检查程序行为的关键。SwitchWare项目使用Caml-lite ML方言来构建活动桥和适合于胶囊的活动网络的超轻量级编程语言（PLAN）。剑桥克星操作系统支持“软”实时连续媒体流量。为了避免QoS串扰，它在单点（系统中可能最低的层）执行处理器多路复用，因此即使大部分中断处理程序的执行也是在调度程序控制下执行的。Nemesis是一个可操作的单地址空间操作系统，通过虚拟地址权限提供保护。Nemesis上的协议是“垂直结构的”，这意味着应用程序使用默认的共享库或私有库，对自己协议处理中涉及的资源负责。资源控制主动网元（Resource Controlled Active Network element， RCANE）可以由SwitchWare和Nemesis的综合构成。这种综合将需要：(1)将Nemesis的QoS管理扩展到由编程语言存根管理；(2)支持Nemesis下的caml - life；(3)开发用于指定QoS的Caml支持；(4)开发基于多种资源（如CPU周期、实际内存、网络带宽）的协同调度的强大支持。这种协同调度与活动网络特别相关，在活动网络中，新资源向网络元素的用户公开。RCANE将产生一种新颖的网络元素，能够支持多媒体流量的QoS，并限制或抵抗多种形式的拒绝服务攻击，包括“接收-活动锁”和TCP SYN-ACK攻击。这两个研究小组有着广泛相似的兴趣，在实验系统工作方面有着卓越的传统，以及合作、人员交流和合作的历史。RCANE是为活动网络元素提供安全、可控虚拟化的独特机会。本提案要求为这一合作努力的美国（宾夕法尼亚大学）部分提供资金；剑桥大学正在向类似于美国国家科学基金会的欧洲机构申请资金。

Advanced applications of Active Networks require support for robust configurable Quality of Service (QoS), and to also prevent or mitigate sophisticated "denial of service" attacks on security. A major unsolved problem for active networks is mapping application requirements into a distributed resource multiplexing strategy. Since this problem bedevils the Internet community as well (viz., IP Telephony, RSVP, etc.) a solution would have broad and immediate impact on the networking community beyond Active Networks.The Penn/Bellcore SwitchWare active networks project uses programming-language restrictions to balance flexibility, security, usability and performance. In contrast to operating system enforced memory protection, the programming language approach can be viewed as restricting the addresses which can be generated by programs. The advantage of this approach is that some restrictions can be enforced once, at compilation time, versus repeatedly at run-time. In addition, programming language technologies such as ML provide strong type-checking, a key to automated checks of program behavior. The SwitchWare project has used the Caml-lite ML dialect to build an active bridge and an ultralightweight Programming Language for Active Networks (PLAN) appropriate for capsules.The Cambridge Nemesis Operating System supports "soft" real-time continuous media traffic. To avoid QoS crosstalk, it performs processor multiplexing at a single point, the lowest possible layer in the system, so that even a large portion of interrupt handler execution is performed under scheduler control. Nemesis is anoperational single-address space operating system, providing protection by means of virtual-address permissions. Protocols on Nemesis are "vertically-structured", meaning that applications are responsible for resources involved in their own protocol processing, using either default shared libraries or privatelibraries.Resource Controlled Active Network Elements (RCANE) can be constructed with a synthesis of SwitchWare and Nemesis. This synthesis will entail: (1) extending the QoS management of Nemesis to be managed byprogramming language stubs; (2) supporting Caml-lite under Nemesis; (3) developing Caml support for specifying QoS; and (4) developing robust support for co-scheduling based on multiple resources, e.g.,CPU cycles, real memory, network bandwidth. This co-scheduling is particularly relevant to Active Networks, where new resources are exposed to users of the network element. RCANE will produce a novelactive network element able to support QoS for multimedia traffic and limit or resist denial-of-service attacks of many forms, including "receive-livelock" and TCP SYN-ACK attacks.The two research groups have broadly similar interests, a tradition of excellence in experimental systems work, and a history of cooperation, personnel exchanges and collaborations. RCANE is a unique opportunityto provide secure, controlled virtualization of active network elements. This proposal requests funds for the U.S. (Penn) portion of this collaborative effort; Cambridge is applying for funds from European analogues of the National Science Foundation.