7,587 research outputs found

    Virtual lines, a deadlock-free and real-time routing mechanism for ATM networks

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    In this paper, we present a routing mechanism and buffer allocation mechanism for an ATM switching fabric. Since the fabric will be used to transfer multimedia traffic, it should provide a guaranteed throughput and a bounded latency. We focus on the design of a suitable routing mechanism that is capable of fulfilling these requirements and is free of deadlocks. We will describe two basic concepts that can be used to implement deadlock-free routing. Routing of messages is closely related to buffering. We have organized the buffers into parallel FIFO's, each representing a virtual line. In this way, we not only have solved the problem of head of line blocking, but we can also give real-time guarantees. We will show that for local high-speed networks, it is more advantageous to have a proper flow control than to have large buffers. Although the virtual line concept can have a low buffer utilization, the transfer efficiency can be higher. The virtual line concept allows adaptive routing. The total throughput of the network can be improved by using alternative routes. Adaptive routing is attractive in networks where alternative routes are not much longer than the initial route(s). The network of the switching fabric is built up from switching elements interconnected in a Kautz topology

    Virtual lines, a deadlock free and real-time routing mechanism for ATM networks

    Get PDF
    In this paper we present a routing mechanism and buffer allocation mechanism for an ATM switching fabric. Since the fabric will be used to transfer multimedia traffic it should provide a guaranteed throughput and a bounded latency. We focus on the design of a suitable routing mechanism that is capable to fulfil these requirements and is free of deadlocks. We will describe two basic concepts that can be used to implement deadlock free routing. Routing of messages is closely related to buffering. We have organized the buffers into parallel fifos, each representing a virtual line. In this way we not only have solved the problem of Head Of Line blocking, but we can also give real-time guarantees. We will show that for local high-speed networks it is more advantageous to have a proper flow control than to have large buffers. Although the virtual line concept can have a low buffer utilization, the transfer efficiency can be higher. The virtual lines concept allows adaptive routing. The total throughput of the network can be improved by using alternative routes. Adaptive routing is attractive in networks where alternative routes are not much longer than the initial route(s). The network of the switching fabric is built up from switching elements interconnected in a Kautz topology

    MIRAI Architecture for Heterogeneous Network

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    One of the keywords that describe next-generation wireless communications is "seamless." As part of the e-Japan Plan promoted by the Japanese Government, the Multimedia Integrated Network by Radio Access Innovation project has as its goal the development of new technologies to enable seamless integration of various wireless access systems for practical use by 2005. This article describes a heterogeneous network architecture including a common tool, a common platform, and a common access. In particular, software-defined radio technologies are used to develop a multiservice user terminal to access different wireless networks. The common platform for various wireless networks is based on a wireless-supporting IPv6 network. A basic access network, separated from other wireless access networks, is used as a means for wireless system discovery, signaling, and paging. A proof-of-concept experimental demonstration system is available

    ISDN at NASA Lewis Research Center

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    An expository investigation of the potential impact of the Integrated Services Digital Network (ISDN) at NASA Lewis Research Center is described. To properly frame the subject, the paper contains a detailed survey of the components of Narrowband ISDN. The principles and objectives are presented as decreed by the Consultative Committee for International Telephone and Telegraph (CCITT). The various channel types are delineated and their associated service combinations are described. The subscriber-access network functions are explained pictorially via the ISDN reference configuration. A section on switching techniques is presented to enable the reader to understand the emergence of the concept of fast packet switching. This new technology is designed to operate over the high bandwidth, low error rate transmission media that characterizes the LeRC environment. A brief introduction to the next generation of networks is covered with sections on Broadband ISDM (B-ISDN), Asynchronous Transfer Mode (ATM), and Synchronous Optical Networks (SONET). Applications at LeRC are presented, first in terms of targets of opportunity, then in light of compatibility constraints. In-place pilot projects and testing are described that demonstrate actual usage at LeRC

    Future benefits and applications of intelligent on-board processing to VSAT services

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    The trends and roles of VSAT services in the year 2010 time frame are examined based on an overall network and service model for that period. An estimate of the VSAT traffic is then made and the service and general network requirements are identified. In order to accommodate these traffic needs, four satellite VSAT architectures based on the use of fixed or scanning multibeam antennas in conjunction with IF switching or onboard regeneration and baseband processing are suggested. The performance of each of these architectures is assessed and the key enabling technologies are identified

    The Design of a System Architecture for Mobile Multimedia Computers

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    This chapter discusses the system architecture of a portable computer, called Mobile Digital Companion, which provides support for handling multimedia applications energy efficiently. Because battery life is limited and battery weight is an important factor for the size and the weight of the Mobile Digital Companion, energy management plays a crucial role in the architecture. As the Companion must remain usable in a variety of environments, it has to be flexible and adaptable to various operating conditions. The Mobile Digital Companion has an unconventional architecture that saves energy by using system decomposition at different levels of the architecture and exploits locality of reference with dedicated, optimised modules. The approach is based on dedicated functionality and the extensive use of energy reduction techniques at all levels of system design. The system has an architecture with a general-purpose processor accompanied by a set of heterogeneous autonomous programmable modules, each providing an energy efficient implementation of dedicated tasks. A reconfigurable internal communication network switch exploits locality of reference and eliminates wasteful data copies

    Gigabit Networks

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    This chapter summarizes what we have learned in the past decade of research into extremely high throughput networks. Such networks are colloquially referred to as Gigabit Networks in reference to the billion bit per second throughput regime they now operate in. The engineering challenges are in the integration of fast transmission systems and high-performance engineering workstations
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