This paper focuses on the design of signaling and mobility control protocols for wireless ATM (W-ATM) systems based on the intelligent network (IN) concepts. The employed signaling protocol architecture aims for priva...
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The divergence between the development of the control system and its environment of technical devices in a complex new machine is difficult to handle and usually not addressed by existent development methods. The pres...
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The divergence between the development of the control system and its environment of technical devices in a complex new machine is difficult to handle and usually not addressed by existent development methods. The presented approach considers these questions and at the same time preserves the essential separation of functional and interface domains. Within each domain progress can be made independently using dedicated software tools. Generators provide implementations running with simulation models as well as partial or complete target implementations. The code is statically deterministic and runs in a simple environment with only a few processes. To confirm the real-time behavior of an implementation the generators also provide worst-case traces. Automatic code generation from models and specifications minimizes programming efforts and coding errors. The concept has been proven in a number of industrial and academic projects.
The most important approaches on Internet economics make various assumptions on pricing policies and services. This study introduces main reasonings for and against pricing as a method to reduce congestion of Internet...
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The most important approaches on Internet economics make various assumptions on pricing policies and services. This study introduces main reasonings for and against pricing as a method to reduce congestion of Internet services. These criteria encompass features of the economic model, the pricing mechanism, and the network model. Moreover necessary basics are outlined to handle general influences. Advantages and drawbacks of economics for communication services are discussed to reveal a structured picture of today's situation, which is driven by technological and economic factors at the same time. Based on a sketchy overview of related work a new volume-based approach for pricing communication services in the Internet is proposed and an implementation architecture is introduced.
The emerging asynchronous transfer mode (ATM) technology provides an end-to-end quality-of-service (QoS) for communication services. However within the local communication area traditionally stochastic network technol...
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The emerging asynchronous transfer mode (ATM) technology provides an end-to-end quality-of-service (QoS) for communication services. However within the local communication area traditionally stochastic network technology like Ethernet has been utilized. Therefore, an alternative approach to provide end-to-end ATM services without a complete replacement of traditional local area networking equipment, has been developed. ATM services are offered over Ethernet, where end-systems are attached via an Ethernet segment to an Ethernet-ATM attachment device (ASHMEN). Applications use common ATM signaling and ATM protocols, such as the ATM adaptation layer 5 (AAL 5) protocol, to setup and maintain end-to-end ATM connectivity. The developed protocol architecture includes a protocol mapping from AAL 5 frames into Ethernet frames which has been efficiently implemented in a UNIX-based workstation environment. QoS guarantees can be provided within the ATM network as usual and are offered additionally within the Ethernet segment which is made possible with Ethernet switching technology and a resource management module implemented in the Ethernet-ATM attachment device.
One of the key factors for efficiency in distributed simulation is the detection of model-inherent concurrency, which is related on the prediction of the future behavior of each logical simulation process. We present ...
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One of the key factors for efficiency in distributed simulation is the detection of model-inherent concurrency, which is related on the prediction of the future behavior of each logical simulation process. We present a generalization of traditional approaches to behavioral prediction which provides more accurate predictions in general and a high degree of scalability in terms of computational and communication overhead. We give a sequential implementation, prove its correctness using concepts from the analysis of real time process networks and then show how these results can be used in distributed simulation.
In this paper, an approach to symbolic model checking of process networks is introduced. It is based on interval decision diagrams (IDDs), a representation of multi-valued functions. Compared to other model checking s...
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In this paper, an approach to symbolic model checking of process networks is introduced. It is based on interval decision diagrams (IDDs), a representation of multi-valued functions. Compared to other model checking strategies, IDDs show some important properties that enable the verification of process networks more adequately than with conventional approaches. Additionally, applications concerning scheduling are shown. A new form of transition relation representation called interval mapping diagrams (IMDs)-and their less general version predicate action diagrams (PADs)-are explained together with the corresponding methods.
Petri nets are an established and well researched means for systems modeling and simulation, but its use in the engineering community is not as widespread as the applicability of the formalism would suggest. A reason ...
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Petri nets are an established and well researched means for systems modeling and simulation, but its use in the engineering community is not as widespread as the applicability of the formalism would suggest. A reason for this might lie in the fact that there is no established concept for the concise presentation of reusable Petri net design knowledge. This paper proposes Petri net design patterns as a style of presentation of such design knowledge ranging from building blocks to architectural considerations. The template for description is introduced using a number of examples taken from our design experience.
The need for algorithms providing synchronization between audio and video data was driven by the advent of multimedia applications in distributed environments. Numerous algorithms have been proposed, but there is a la...
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The need for algorithms providing synchronization between audio and video data was driven by the advent of multimedia applications in distributed environments. Numerous algorithms have been proposed, but there is a lack of methodologies to assess these algorithms, to compare them and to determine the algorithm best suited for a given networking and end-system environment and application. In this paper a methodology to assess synchronization algorithms for distributed multimedia applications is presented. The methodology is based on four quality of service (QoS) parameters for synchronization comprising: asynchrony, synchronization error probability, synchronization delays, and buffer requirements. An analytical analysis of these parameters is performed. A key feature of this methodology, is that it parameterizes the network, the end-system, and the application. Thus, it allows for the assessment of any synchronization algorithm independent from the network and end-system. Influences of the infrastructure on synchronization can be determined by the proposed methodology.
Present day routers typically employ monolithic operating systems which are not easily upgradable and extensible. With the rapid rate of protocol development it is becoming increasingly important to dynamically upgrad...
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ISBN:
(纸本)9781581130034
Present day routers typically employ monolithic operating systems which are not easily upgradable and extensible. With the rapid rate of protocol development it is becoming increasingly important to dynamically upgrade router software in an incremental fashion. We have designed and implemented a high performance, modular, extended integrated services router software architecture in the NetBSD operating system kernel. This architecture allows code modules, called plugins, to be dynamically added and configured at run time. One of the novel features of our design is the ability to bind different plugins to individual flows; this allows for distinct plugin implementations to seamlessly coexist in the same runtime environment. High performance is achieved through a carefully designed modular architecture; an innovative packet classification algorithm that is both powerful and highly efficient; and by caching that exploits the flow-like characteristics of Internet traffic. Compared to a monolithic best-effort kernel, our implementation requires an average increase in packet processing overhead of only 8%, or 500 cycles/2.1ms per packet when running on a P6/233.
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