here is a flurry of activity in the networking community developing advanced services networks. Although the focus of these efforts varies widely from per-flow service definitions like integrated services (IntServ) [1,2] to service frameworks like Xbind [3], they share the overall goal of evolving the Internet service model from what is essentially a basic bitway pipe to a sophisticated infrastructure capable of supporting novel advanced services.In this article we consider a network environment that comprises not only communication services, but storage and computation resources as well. By packaging storage/computation resources together with communication services, value-added service providers will be able to support sophisticated services such as intelligent caching, video/audio transcoding and mixing, virtual private networking, virtual reality games, and data mining. In such a service-oriented network, value-added services can be composed in a hierarchical fashion: applications invoke high-level service providers, which may in turn invoke services from lower-level service providers. Providers in the top of the hierarchy will typically integrate and add value to lower-level services, while the lowest-level services will supply basic communication and computational support. Since services can be composed hierarchically, both applications and service providers will be able to combine their own resources with resources or services delivered by other service providers to create a high-quality service for their clients. The design of such a service-oriented network poses challenges in several areas, such as resource discovery, resource management, service composition, billing, and security. In this article we focus on the resource management architecture and algorithms for such a network.Service-oriented networks have several important differences from traditional networks that make existing network resource management inadequate. First, while traditional communication-oriented network services are provided by switches and links, value-added services will have to manage a broader set of resources that includes computation, storage, and services from other providers. Moreover, interdependencies between differ-0890-8044/01/$10.00 AbstractThe Internet is rapidly changing from a set of wires and switches that carry packets into a sophisticated infrastructure that delivers a set of complex value-added services to end users. Services can range from bit transport all the way up to distributed value-added services like video teleconferencing, virtual private networking, data mining, and distributed interactive simulations. Before such services can be supported in a general and dynamic manner, we have to develop appropriate resource management mechanisms. These resource management mechanisms must make it possible to identify and allocate resources that meet service or application requirements, support both isolation and controlled dynamic sharing of resources across services and applications sharing physical resources, a...

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The Internet is rapidly changing from a set of wires and switches that carry packets to a sophisticated infrastructure that delivers a set of complex value-added services to end users. Services can range from bit transport all the way up to distributed value-added services like video teleconferencing, virtual private networking, data mining, and distributed interactive simulations. Before such services can be supported in a general and dynamic manner, we have to develop appropriate resource management mechanisms. These resource management mechanisms must make it possible to identify and allocate resources that meet service or application requirements, support both isolation and controlled dynamic sharing of resources across services and applications sharing physical resources, and be customizable so services and applications can tailor resource usage to optimize their performance. The Darwin project has developed a set of customizable resource management mechanisms that support value-added services. In this paper we present and motivate these mechanisms, describe their implementation in a prototype system, and describe the results of a series of proof-of-concept experiments.

In all-to-all personalized communication (AAPC), every node of a parallel system sends a potentially unique packet to every other node. AAPC is an important primitive operation for modern parallel compilers, since it is used to redistribute data structures during parallel computations. As an extremely dense communication pattern, AAPC causes congestion in many types of networks and therefore executes very poorly on general purpose, asynchronous message passing routers.We present and evaluate a network architecture that executes allto-all communication optimally on a two-dimensional torus. The router combines optimal partitions of the AAPC step with a selfsynchronizing switching mechanism integrated into a conventional wormhole router. Optimality is achieved by routing along shortest paths while fully utilizing all links. A simple hardware addition for synchronized message switching can guarantee optimal AAPC routing in many existing network architectures.The flexible communication agent of the iWarp VLSI component allowed us to implement an efficient prototype for the evaluation of the hardware complexity as well as possible software overheads. The measured performance on an 8 8 torus exceeded 2 GigaBytes/sec or 80% of the limit set by the raw speed of the interconnects. We make a quantitative comparison of the AAPC router with a conventional message passing system. The potential gain of such a router for larger parallel programs is illustrated with the example of a two-dimensional Fast Fourier Transform.

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