We present a novel approach to building and deploying network protocols. The approach is based on mobile code, demand loading, and caching techniques. The architecture of our system allows new protocols to be dynamica...
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ISBN:
(纸本)0780347838
We present a novel approach to building and deploying network protocols. The approach is based on mobile code, demand loading, and caching techniques. The architecture of our system allows new protocols to be dynamically deployed at both routers and end systems, without the need for coordination and without unwanted interaction between co-existing protocols In this paper, we describe our architecture and its realization in a prototype implementation. To demonstrate how to exploit our architecture, we present two simple protocols that operate within our prototype to introduce multicast and mobility services into a network that initially lacks them.
The paper introduces a generic object model that makes instances of a network service accessible to the management system. This way, an open interface between the service delivery and the service management systems is...
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ISBN:
(纸本)0780347838
The paper introduces a generic object model that makes instances of a network service accessible to the management system. This way, an open interface between the service delivery and the service management systems is defined. The model includes a set of cooperating objects that can be customized for particular service and management requirements. By applying this model to the design of mcast, an ATM multicast service, we enable the management system to monitor and control mcast sessions. To validate our approach, we have implemented mcast and the management functions on two different platforms: (1) on a high-performance emulation platform, which allows as to study the system's dynamic behavior and scaling properties in various scenarios;(2) on a broadband testbed running xbind, on which network services can be fully implemented, including the transport between multimedia devices. CORBA technology is used for building the service control system as well as the management system..
作者:
Muir, SSmith, JUniv Penn
Dept Comp & Informat Sci Distributed Syst Lab Philadelphia PA 19104 USA
As the role of the computer as a communications device increases, we must reexamine the role an operating system plays in managing resources to support users. In support of general purpose computation, symmetric multi...
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ISBN:
(纸本)0780347838
As the role of the computer as a communications device increases, we must reexamine the role an operating system plays in managing resources to support users. In support of general purpose computation, symmetric multiprocessing has generally proven better than attached processors, master/slave, or other configurations. In this paper, we examine a different approach, an Asymmetric Multiprocessor Operating System (AsyMOS), which applies a subset of available processors toward supporting an abstraction of a virtual 'smart device'. As a software solution, AsyMOS is able to exploit the cost/performance advantages of sharing memory and packaging that accrue to small scale SMPs, while tracking processor performance much more tightly than front-end processors can. The ability to move of functionality into the 'smart' device is demonstrated in the context of a network subsystem. Application-specific resource management is facilitated by the exporting of interfaces directly to applications. A prototype implementation of the architecture running on commodity hardware demonstrates quantitative advantages over a traditionally structured SMP operating system and provides a framework for further research into functional devolution.
The Tempest framework provides a programmable network environment by allowing the dynamic introduction and modification of network services at two levels of granularity. First, the switchlet and associated virtual net...
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The Tempest framework provides a programmable network environment by allowing the dynamic introduction and modification of network services at two levels of granularity. First, the switchlet and associated virtual network concepts enable the safe introduction of alternative control architectures into an operational network. The timescales over which such new control architectures can be introduced might vary from, for example, a video conferencing specific control architecture, which is active only for the duration of the conference, to a new version of a general purpose control architecture, which might be active for several months or longer. Second, the Tempest Framework allows refinement of services at a finer level of granularity by means of the connection closure concept. In this case modification of services can be performed at an application-specific level. These attributes of the Tempest framework allows service providers to effectively become network operators for some well defined partition of the physical network. This enables them to take advantage of the knowledge they possess about how the network resources are to be used, by programming their own specially tailored control architecture. This, as our work with the Tempest shows, is a spur to creativity allowing many of the constraints imposed on operators and end users to be rethought and for new techniques to be quickly and safely introduced into working networks.
This paper puts forward the benefits of a network approach in the design of electrical and electronic architectures for underwater systems. The subject is illustrated through two design and realisation examples intend...
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ISBN:
(纸本)0780350456
This paper puts forward the benefits of a network approach in the design of electrical and electronic architectures for underwater systems. The subject is illustrated through two design and realisation examples intending to meet distinct requirements in two different areas : On the one hand, integrating a fieldbus on the manned submarine NAUTILE for multiplexing the controls/commands and decreasing the wiring complexity, on the other hand, making available an open and reliable means of handling and logging data within a benthic station. The studies described in these two examples both resulted in the use of a network originating from the automotive industry : the Controller Area network.
The proceedings contain 43 papers. The topics discussed include: emulating ATM network impairments;a hypertext markup language interface for multi-product database libraries;hiding distributed complexities: attribute ...
ISBN:
(纸本)0780399145
The proceedings contain 43 papers. The topics discussed include: emulating ATM network impairments;a hypertext markup language interface for multi-product database libraries;hiding distributed complexities: attribute based programming;performance evaluation of ATM and gigabit networks;intelligent fusion and asset management processor;improving TCP performance over wireless ATM networks;classification and characterization of host network interface architectures;SCPlib: A concurrent programming library for programming heterogeneous networks of computers;an introduction to the mathematics of end-to-end quality of service in complex distributed information systems (DIS);EPIC-extensible program for intrusion control;open infrastructure for scalable intrusion detection;detecting subtle system changes using digital signatures;steganalysis: the investigation of hidden information;information fusion techniques for network intrusion detection;a knowledge base system for the design and manufacture of injection-molded plastic products;fusion of spatial information systems and genetic algorithm for transmitter location in wireless networks;and distributed knowledge networks.
Subscription architectures have been used or considered for the implementation of distributed systems across the spectrum from hardware, through offline programming and simulation, to very high level agent-based appro...
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ISBN:
(纸本)0780399145
Subscription architectures have been used or considered for the implementation of distributed systems across the spectrum from hardware, through offline programming and simulation, to very high level agent-based approaches. The "publish and subscribe" paradigm is attractive for multiprocessor systems that can be characterised as asynchronous, loosely coupled and coarse grained. As such systems grow in size and complexity, however the overheads and bottlenecks arising from the need to route messages among a complex and dynamic web of subscribers and publishers can often overwhelm the benefits of distribution. There is thus a need for efficient implementations of these architectures that avoid the need for messages having to pass through centralised routing processes. This paper explores the proposition that broadcast network transport layers with multicast support can support highly efficient implementations of subscription architectures in a wide variety of distributed systems at all levels of the network hierarchy and abstraction. The work described focuses particularly on two currently active projects: 1. a simulation tool for the design of advanced submersible vehicles that will run on a cluster of workstations and hardware components connected by ethernet and the internet. 2. the control architecture for a land vehicle implemented as multiple microprocessors connected by a CAN bus. The paper draws out the common features of these two projects in order to make some generalisations about the benefits that can accrue to implementations of subscription architectures that use multicast supported by hardware. It explores the use of multicast groups to implement subscription "regions" - that is the ability of subscribers to specify dynamically subsets of data to be supplied for a particular subscription.
Six questions are posed that are likely to be of interest to one considering applying the DHP methodology. Tentative answers to these questions are provided in the last section of the paper. As a basis for these, the ...
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Six questions are posed that are likely to be of interest to one considering applying the DHP methodology. Tentative answers to these questions are provided in the last section of the paper. As a basis for these, the paper first describes observations made from a series of explorations into various aspects of using the DHP method to design the controller for the pole-cart benchmark problem. Parameters of the explorations included training gains, plant parameter variations, fidelity of plant model, controller sampling rates, networkarchitectures, training strategies, and generalization tests.
The idea of software architecture has been around since 1960's and the earliest examples were mathematical subroutines, with business application generators representing some of the architecture systems. During th...
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ISBN:
(纸本)0818685859
The idea of software architecture has been around since 1960's and the earliest examples were mathematical subroutines, with business application generators representing some of the architecture systems. During the intervening years three technical developments have occurred. First, the range of application platforms has exploded, with embedded, desktop, network, and Internet based systems emerging. Second, the range of applications being built has expanded along the with the breadth of the computer. Thirdly, the programming languages, programming models, and tools have increased tremendously in their sophistication and abstraction capabilities. This paper a presents a discussion to shed light on these and these and other factor, together with the risks ahead.
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