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Modeling, Analysis and Simulation of Computer and Telecommunication Systems, 2000. Proceedings. 8th International Symposium on

Date Aug. 29 2000-Sept. 1 2000

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Displaying Results 1 - 25 of 72
  • 8th International Symposium on Modeling, Analysis and Simulation of Computer and Telecommunication Systems [front matter]

    Page(s): i - xiii
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    Freely Available from IEEE
  • A performance model of broadcast communication in wormhole-routed hypercubes

    Page(s): 98 - 105
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    Many analytical models of wormhole-routed networks have been proposed over the past few years. Most of these models, however, have been developed for unicast (or point-to-point) communication. There has been comparatively little activity in the area of analytical models of collective communication, such as broadcast. As a result, most existing studies have relied on simulation to evaluate the performance merits of collective communication algorithms. This paper presents a new analytical model for predicting broadcast latency in the hypercube. Results obtained through simulation experiments show that the model exhibits a good degree of accuracy in predicting message latency under different working conditions. View full abstract»

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  • Using complete system simulation for temporal debugging of general purpose operating systems and workloads

    Page(s): 191 - 198
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    Digital convergence is precipitating the addition of soft real-time applications to mainstream desktop and server operating environments. Most traditional debuggers for mainstream systems lack a notion of temporal correctness, making them unsuitable for real-time system design and analysis. We propose leveraging complete system simulation to build a temporal debugger which is capable of analyzing mixed real-world workloads. Traditional real-time system debuggers based on simulation utilize slow, but accurate, simulators. Complete system simulators accept an approximate model of time in exchange for higher performance. The higher performance allows these simulators to analyze high-end commercial operating systems and applications. We describe a temporal debugger design based on complete system simulation and report on some early experiences in analyzing a simple workload. The tool offers a non-intrusive, predictable environment for debugging complex workloads with partial real-time constraints. The simulator foundation allows for interactive debugging of time-critical sequences while preserving a model of execution time flow. View full abstract»

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  • Keynote address - new challenges in the performance evaluation of communication networks

    Page(s): 227 - 228
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    Provides an abstract of the keynote presentation and a brief professional biography of the presenter. The complete presentation was not made available for publication as part of the conference proceedings. View full abstract»

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  • Author index

    Page(s): 583 - 584
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    Freely Available from IEEE
  • A performance analysis framework for a system lifespan

    Page(s): 240 - 255
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    Assessing the performance of complex systems is important but difficult for all users in every phase of a system lifespan. Current performance analysis tools have proven successful but have not been widely used outside the laboratory. Laboratory-oriented analyses, queries and views, and rigid, insufficiently documented tool architectures create this situation. This paper presents a framework for addressing these limitations, including multiple abstraction level analysis and an open software architecture to address these limitations. An examination of this framework illustrates its capabilities for varied analysis environments and users View full abstract»

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  • The design of ATM virtual path connection networks with service separation

    Page(s): 424 - 431
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    Presents an efficient algorithm to compute an optimal service-separated virtual path connection network (VPCN) consisting of several logical subnetworks, one for each service class. The algorithm implements a bandwidth market where each VPC computes the prices at which it is willing to buy and sell bandwidth. These prices determine the allocation of bandwidth to virtual path connections (VPCs) in a series of transactions. After each transaction, the VPCN is adjusted, bandwidth supplies and prices are adjusted, and the algorithm computes the next bandwidth transaction. We apply our algorithm and another method to design an optimal service-separated VPCN for a small network consisting of 10 nodes and two service classes. Both methods yield near-identical revenues, though our algorithm requires a fraction of the computational resources required by the other method. We next apply our algorithm to compute optimal service-separated VPCNs for two larger networks of 20 and 55 nodes, each with six service classes View full abstract»

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  • Modeling and analysis of UMTS hierarchical networks

    Page(s): 432 - 437
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    This paper presents an incremental computation performance evaluation algorithm for a UMTS (universal mobile telecommunication system) network model. We show that, when solving a set of models for different parameter values, our algorithm has a significant gain over classical methods. We derive performance criteria, such as new call blocking and dropping handover probability, for UMTS networks View full abstract»

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  • Sources and characteristics of Web temporal locality

    Page(s): 28 - 35
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    Temporal locality of reference in Web request streams emerges from two distinct phenomena: the long-term popularity of Web documents and the short-term temporal correlations of references. We show that the commonly-used distribution of inter-request times is predominantly determined by the power law governing the long-term popularity of documents. This inherent relationship tends to disguise the existence of short-term temporal correlations. We propose a new and robust metric that enables accurate characterization of that aspect of temporal locality. Using this metric, we characterize the locality of reference in a number of representative proxy cache traces. Our findings show that there are measurable differences between the degrees (and sources) of temporal locality across these traces View full abstract»

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  • Fieldbus network simulation using a time extended Estelle formalism

    Page(s): 92 - 97
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    Functional and performance validation is an important issue addressed by fieldbus network design. Simulation support is needed for early functional validation and performance. Fieldbus network simulation requires models of real field devices. The models need to be described in a modeling language and implemented into a simulation environment. Estelle has been chosen to specify in a formal language the PROFIBUS fieldbus protocol. A formal protocol specification insures unambiguous interpretation, enables conformance tests and improves interoperability, which are important issues in the fieldbus systems engineering process. We use Estelle as a general modeling and simulation language for the design of a fieldbus network simulation tool. We present a modeling methodology which overcomes Estelle shortage in performance evaluation support. The approach is demonstrated on a PROFIBUS-DP network simulation View full abstract»

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  • A performance comparison of monofractal and multifractal traffic streams

    Page(s): 214 - 223
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    Focuses on the differences between monofractal and multifractal network traffic, both in terms of modeling approaches and in terms of practical impacts on network performance. Empirical traffic traces are used in the parameterization and evaluation of traffic models. Simulation is used to evaluate the performance differences between monofractal and multifractal traffic, both for individual traffic streams and for aggregations of traffic streams. The simulation results indicate that multifractal traffic offers greater potential for multiplexing gains, both within and across sources. The sensitivity of these results to source characteristics and switch buffer size is also explored View full abstract»

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  • simCore: an event-driven simulation framework for performance evaluation of computer systems

    Page(s): 274 - 280
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    In designing complex systems, a performance evaluation model is essential in determining a system configuration and identifying performance bottlenecks. Several C++-based general-purpose simulation tools such as systemC and CynLib have also been introduced. However, these tools are cycle-based, which simulates a system synchronously under the assumption that all modules are invoked every cycle, thus eliminating scheduling overhead. In order to simulate a system containing multiple clocks or asynchronous circuits with accuracy, an event-driven approach is highly desirable. We have developed an event-driven framework of computer system simulation in C++, called simCore, which is mainly targeted for performance evaluation simulation of computer systems, providing concurrent execution of multiple modules and event-driven module interaction mechanisms. However, in order to demonstrate its cycle-accuracy and high simulation speed, we compared two MIPS-based system simulators, one based on the C++-based event-driven simulation core and the other based on Verilog-XL View full abstract»

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  • An integrative scheme of differentiated services: modeling and performance analysis

    Page(s): 441 - 448
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    Proposes an integrative scheme of differentiated services (DiffServ) for the Internet. In our scheme, the quality of service (QoS) is ranked according to the levels of both importance and urgency, which makes the service negotiation and the implementation mechanism more flexible and universal. Samples of the implementation mechanism at the edge nodes and interior nodes are described, and stochastic Petri net models of them are given. The performance of the per-hop behavior (PHB) implementation mechanism is analyzed, under both Poisson and self-similar arrivals. An approximate analysis technique of decomposition and iteration is used to reduce the complexity. For self-similar traffic, an MMPP (Markov-modulated Poisson process) based self-similar model of A.T. Andersen et al. (1998) is used View full abstract»

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  • Towards a rate-based TCP protocol for the Web

    Page(s): 36 - 45
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    TCP's sliding window flow control mechanism often leads to bursty packet traffic in the Internet. In the presence of network congestion, multiple packet losses can occur degrading the performance of TCP and the user-perceived performance of the Web. This paper presents a rate-based pacing (RBP) mechanism for TCP flow control. This mechanism can reduce the burstiness of TCP packet transmission and improve document transfer performance. Simulation is used to evaluate the performance of this mechanism. Our RBP TCP protocol is found to provide similar performance to Reno TCP in terms of throughput and packet loss for bulk data transfers, but lower packet loss and 10-20% lower latency than Reno TCP for Web-like document transfers View full abstract»

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  • Parallel co-simulation of conventional and active networks

    Page(s): 291 - 298
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    Discrete event simulations are widely used to study and analyze active and conventional networking architectures and protocols. Active networks must coexist and communicate with conventional networks to effectively utilize and extend the infrastructure of the Internet. Hence, large scale network simulations containing both conventional and active components should be conducted to study crucial scalability and performance issues. In this paper, a framework to enable parallel co-simulation of conventional and active networks is described. The framework integrates ANSE, a parallel active network simulation environment, with NS, a popular sequential network simulator. Object oriented techniques that completely insulate the application modules from the modifications have been employed for parallelizing NS in order to eliminate changes to the network models. This paper presents the design and implementation of the parallel co-simulation framework along with the results obtained from our co-simulation studies. Our studies indicate that parallel simulation techniques considerably reduce simulation times for even small sized network models View full abstract»

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  • A parallel discrete event IP network emulator

    Page(s): 315 - 322
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    Testing distributed applications over the Internet is fraught with problems: due to the inability to control a wide area network consistent, reproducible performance experiments are not possible. A system is described that uses a parallel discrete event simulator that can act as a real-time network emulator. Real Internet Protocol (IP) traffic generated by application programs running on user workstations can interact with modelled traffic in the emulator; thus providing a controlled test environment for distributed applications. Parallel execution enables the emulator to simulate large virtual networks and to model traffic interactions that could not be done in real-time sequentially. This paper gives an overview of the emulator and explores the various external data routing methods that the emulator supports. These routing methods allow the emulator to be operated in shared environments with certain constraints, as well as in dedicated test environments. Preliminary performance results are included View full abstract»

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  • A cost-effective load balanced adaptive routing scheme for mesh-connected networks

    Page(s): 532 - 538
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    A highly cost-effective adaptive routing algorithm for n-D meshes is designed. It employs only two virtual channels. The planar routing and the 2D VBMAR are used as constructs for it. Routing freedom is greatly enhanced to improve performance. As a result, the algorithm features load balance and high adaptivity. Deadlock freedom of the algorithm is proved. Extensive simulations show that it not only outperforms an algorithm with equal virtual channels, but also excels the fully routing algorithm with much more virtual channels View full abstract»

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  • Simulation of fluid stochastic Petri nets

    Page(s): 231 - 239
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    Describes a method for the simulation of fluid stochastic Petri nets (FSPNs). The FSPNs are a promising formalism for modeling hybrid dynamic systems, i.e. systems having both discrete and continuous components that evolve over time. Unfortunately, an analytical evaluation of performance measures for such nets requires the solution of a complex system of integro-differential equations whose numerical analysis often becomes a formidable task. One possible way for computing such performance measures is the use of simulative approaches. Because of the mixed (discrete and continuous) state space, the simulation of FSPNs models poses some interesting challenges, which are addressed in this paper. The paper provides a simulative approach for deriving performance measures for a class of FSPNs. The techniques described in the paper are included in a simulation tool for this class of FSPNs View full abstract»

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  • A performance comparison of energy consumption for Mobile Ad Hoc Network routing protocols

    Page(s): 57 - 64
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    The design of efficient routing protocols is a fundamental problem in a Mobile Ad-Hoc Network (MANET). Many different protocols have been proposed in the literature, each one based on different characteristics and properties. Some of these protocols have been studied and their performances have been evaluated in detail, focusing on aspects such as routing overhead latency and route length. We concentrate on the energy consumption issues of routing protocols. We present a performance comparison of the DSR, AODV, TORA and DSDV routing protocols with respect to energy consumption, evaluating how the different approaches and algorithms affect the energy usage in mobile devices View full abstract»

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  • Geographic load balancing for scalable distributed Web systems

    Page(s): 20 - 27
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    Users of highly popular Web sites may experience long delays when accessing information. Upgrading content site infrastructure from a single node to a locally distributed Web cluster composed by multiple server nodes provides limited relief, because the cluster wide-area connectivity may become the bottleneck. A better solution is to distribute Web clusters over the Internet by placing content nodes in strategic locations. A geographically distributed architecture where the Domain Name System (DNS) servers evaluate network proximity and users are served from the closest cluster reduces network impact on response time. On the other hand, serving closest requests only may cause unbalanced servers and may increase system impact on response time. To achieve a scalable Web system, we propose to integrate DNS proximity scheduling with an HTTP request redirection mechanism that any Web server can activate. We demonstrate through simulation experiments that this further dispatching mechanism augments the percentage of requests with guaranteed response time, thereby enhancing the Quality of Service of geographically distributed Web sites. However, HTTP request redirection should be used selectively because the additional round-trip increases network impact on latency time experienced by users. As a further contribution, this paper proposes and compares various mechanisms to limit reassignments with no negative consequences on load balancing View full abstract»

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  • Network path pricing: a QoS-based model

    Page(s): 457 - 465
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    A critical question facing network designers is how real-time applications can fairly share communication resources while simultaneously obtaining sufficient quality-of-service (QoS) levels from the network. This paper presents an end-to-end solution to this problem that combines an economic pricing model for resource sharing with a QoS network model. We describe a measurement-based approach for QoS path pricing that results in near-optimal resource allocation policies between QoS and best-effort traffic. We also present the results of a large-scale simulation study that shows how this pricing scheme increases both end-user value and system throughput with minimal computational overhead View full abstract»

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  • Performance analysis of an N×N ATM switch with Markov modulated Poisson process under back-pressure mechanism

    Page(s): 416 - 423
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    In this paper we present a performance study of an input/output buffered type ATM switch with backpressure mechanism with an MMPP process as input. The backpressure is exerted at the Head of Line (HOL) level to prevent output buffer cell loss. MMPP process is chosen due to its bursty nature able to capture multimedia source characteristics such as data and voice. We propose an approximate method to calculate the total waiting time in the switch. Numerical examples will be given for two states MMPP to quantitatively show the effects of output buffer size b on performance switch. The analysis is done by using structured stochastic matrices of M/G/I type and the obtained results extend those related to scalar case (Poisson process) View full abstract»

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  • An approach to on-line predictive detection

    Page(s): 549 - 556
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    Predicting network performance problems enables network operators to take corrective actions in advance of service disruptions. Typically, service problems are detected by tests that compare a metric (e.g., response time) to a threshold. The authors present an online algorithm for predicting the probability of threshold violations over a time horizon. The algorithm uses two cascaded submodels. The first removes non-stationarities by employing a discrete time Kalman filter in combination with analysis of variance. We derive parameters of the Kalman filter from differential equations that describe characteristics of the data. The second submodel estimates the probability of threshold violations by using a second order autoregressive model in combination with change-point detection. Using data from a production Web server, we evaluate our approach and show that it produces average accuracies that are comparable to those of an offline algorithm. However, our online algorithm produces predictions with considerably smaller variances. Further advantages of our approach are: (a) requiring much less data than the offline technique, one day versus multiple months; and (b) adapting to changes in the system and workloads since parameters are estimated online View full abstract»

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  • The synTraff suite of traffic modeling toolkits

    Page(s): 333 - 340
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    Describes three visually interactive tools for the analysis, modeling and generation of long-range dependent (LRD) network traffic: (1) the synTraff toolkit uses a three-step modeling approach based on F-ARIMA (fractal autoregressive integrated moving average) processes to generate monofractal traffic; (2) the WsynTraff toolkit implements the wavelet-domain independent Gaussian (WIG) model (S. Ma et al., 1998) for representing multifractal traffic; and (3) the MsynTraff toolkit models multifractal traffic using the multifractal wavelet model (MWM) (V. Ribeiro et al., 1999). All three tools can be used to generate synthetic LRD traffic streams for use in network simulations View full abstract»

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  • Profiling I/O interrupts in modern architectures

    Page(s): 115 - 123
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    As applications grow increasingly communication-oriented, interrupt performance quickly becomes a crucial component of high performance I/O system design. At the same time, accurately measuring interrupt handler performance is difficult with the traditional simulation, instrumentation, or statistical sampling approaches. One of the most important components of interrupt performance is cache behavior. This paper presents a portable method for measuring the cache effects of I/O interrupt handling using hardware performance counters. The method is demonstrated on two commercial platforms with different architectures, the SGI Origin 200 and the Sun Ultra-1. This case study uses the methodology to measure the overhead of the two most common forms of interrupts: disk and network interrupts. It demonstrates that the method works well and is reasonably robust. In addition, the results show that network interrupts have larger cache footprints than disk interrupts, and behave very differently on both platforms, due to significant differences in OS organization View full abstract»

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