Emerging lambda-Grid systems employ wavelength-routed network with optical switches to enable dynamic on-demand lightpaths with multi-gigabit rate bandwidth to interconnect shared computing clusters of user domains. User-centric lambdaGrid systems enable user domains to act as distributed connectivity providers of shared wavelength resources; and as distributed network control service providers of brokering shared wavelength resources and of provisioning scheduled lightpaths. To support user-centric lambda-Grid systems, the proposed Dynamic User-centric Switched Optical Network (DUSON) architecture employs an Intelligent Control Service Proxy (ICSP) at each user domain to support wavelength connectivity brokerage and lightpath provisioning/restoration middleware for user applications to control on-demand lightpaths. Furthermore, ICSP employs the proposed Robust Fast Optical Reservation Protocol (RFORP) during lightpath provisioning/restoration to minimize wavelength reservation blocking and delay via localized rerouting and parallel concurrent wavelength reservation processing respectively.

Abstract. Tele-Immersive applications possess an unusually broad range of networking requirements. As high-speed and Quality of Service-enabled networks emerge, it will becoming more difficult for developers of Tele-Immersion applications, and networked applications in general, to take advantage of these enhanced services. This paper proposes an adaptive networking framework to ultimately allow applications to optimize their network utilization in pace with advances in networking services. In working toward this goal, this paper will present a number of networking techniques for improving performance in tele-immersive applications and examines whether the Differentiated Services mechanism for network Quality of Service is suitable for Tele-Immersion. IntroductionTele-Immersion is the integration of collaborative virtual reality (VR) with audio and video conferencing in the context of data-mining and significant computation. The ultimate goal of Tele-Immersion is not only to reproduce a real face-to-face meeting in every detail, but to provide the "next generation" interface for collaborators, world-wide, to work together in a virtual environment that is seamlessly enhanced by computation and large databases. When participants are Tele-Immersed, they are able to see and interact with each other in a shared virtual environment. They are able to query and visualize data stores and steer complex scientific and engineering simulations [1].One of the challenges of Tele-Immersion is that it poses diverse requirements of the underlying networks ( Figure 1). For example, to convey audio and gestures of virtual participants (avatars,) low network latency is required; to distribute state updates, low latency but reliable data transmission is preferred; and to distribute data sets high-speed bulk data transfer is needed. In this paper, we will present our most recent work in exploiting advanced networking techniques to optimize data distribution in Tele-Immersion. We will describe our experiences in using Quality-ofService-enabled high-speed networks for supporting Tele-Immersion. We will structure this work by proposing an adaptive networking framework to allow application developers to map their data distribution requirements to suitable networking services. We believe that as networking technology becomes more complex, application developers will have to rely increasingly on intelligent adaptive systems to make decisions on how to optimally distribute their data over them. The work discussed in this paper serves as a starting point toward that ultimate goal. Adaptive Networking for Tele-ImmersionWe propose an intelligent adaptive networking system ( Figure 2) consisting of a Strategy Selector, Adaptive Controller and three supporting services: a Resource Monitor, a Quality of Service (QoS) Provisioner and a collection of network transport mechanisms. The Strategy Selector's role is to take application-specified data delivery requirements (e.g. bandwidth, latency, jitter, reliability, etc) and translate them into networki...