423 research outputs found

    Low-Latency Routing on Mesh-Like Backbones

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    Early in in the Internet's history, routing within a single provider's WAN centered on placing traffic on the shortest path. More recent traffic engineering efforts aim to reduce congestion and/or increase utilization within the status quo of greedy shortest-path first routing on a sparse topology. In this paper, we argue that this status quo of routing and topology is fundamentally at odds with placing traffic so as to minimize latency for users while avoiding congestion. We advocate instead provider backbone topologies that are more mesh-like, and hence better at providing multiple low-latency paths, and a routing system that directly considers latency minimization and congestion avoidance while dynamically placing traffic on multiple unequal-cost paths. We offer a research agenda for achieving this new low-latency approach to WAN topology design and routing

    A Survey on Communication Networks for Electric System Automation

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    Published in Computer Networks 50 (2006) 877–897, an Elsevier journal. The definitive version of this publication is available from Science Direct. Digital Object Identifier:10.1016/j.comnet.2006.01.005In today’s competitive electric utility marketplace, reliable and real-time information become the key factor for reliable delivery of power to the end-users, profitability of the electric utility and customer satisfaction. The operational and commercial demands of electric utilities require a high-performance data communication network that supports both existing functionalities and future operational requirements. In this respect, since such a communication network constitutes the core of the electric system automation applications, the design of a cost-effective and reliable network architecture is crucial. In this paper, the opportunities and challenges of a hybrid network architecture are discussed for electric system automation. More specifically, Internet based Virtual Private Networks, power line communications, satellite communications and wireless communications (wireless sensor networks, WiMAX and wireless mesh networks) are described in detail. The motivation of this paper is to provide a better understanding of the hybrid network architecture that can provide heterogeneous electric system automation application requirements. In this regard, our aim is to present a structured framework for electric utilities who plan to utilize new communication technologies for automation and hence, to make the decision making process more effective and direct.This work was supported by NEETRAC under Project #04-157

    Optical fibre local area networks

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    cISP: A Speed-of-Light Internet Service Provider

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    Low latency is a requirement for a variety of interactive network applications. The Internet, however, is not optimized for latency. We thus explore the design of cost-effective wide-area networks that move data over paths very close to great-circle paths, at speeds very close to the speed of light in vacuum. Our cISP design augments the Internet's fiber with free-space wireless connectivity. cISP addresses the fundamental challenge of simultaneously providing low latency and scalable bandwidth, while accounting for numerous practical factors ranging from transmission tower availability to packet queuing. We show that instantiations of cISP across the contiguous United States and Europe would achieve mean latencies within 5% of that achievable using great-circle paths at the speed of light, over medium and long distances. Further, we estimate that the economic value from such networks would substantially exceed their expense

    Extending HyperTransport Protocol for Improved Scalability

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    HyperTransport 3.10 is the best open standard communication technology for chip-to-chip interconnects. However, its extraordinary features are of little help when building mid- and large-scale systems because it is unable to natively scale beyond 8 computing nodes. Therefore, it must be complemented by other interconnect technologies. The HyperTransport Consortium has intensively stimulated discussions among its high-level members in order to overcome those shortcomings. The result is the High Node Count HyperTransport Specification, which defines protocol extensions to the HyperTransport I/O Link Specification Rev. 3.10 that enable HyperTransport to natively support high numbers of computing nodes, typical of large scale server clustering and High Performance Computing (HPC) applications. This extension has been carefully designed in such a way that it extends the maximum number of connected devices to a number large enough to support current and future scalability requirements, while preserving the excellent features that made HyperTransport successful and keeping full backward compatibility with it
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