Showing papers on "Network traffic simulation published in 2002"

GloMoSim: A Scalable Network Simulation Environment

Abstract: Large-scale hybrid networks that include wireless, wired, and satellite based communications are becoming common in both military and commercial situations. This paper describes a scalable simulation environment called GloMoSim (for Global Mobile Information System Simulator) that effectively utilizes parallel execution to reduce the simulation time of detailed high-fidelity models of large communication networks. The paper also presents a set of case studies that evaluate the performance of large wireless networks with thousands of nodes and compares the impact of different lower layer protocols on the performance of typical applications.

SUMO (Simulation of Urban MObility) - an open-source traffic simulation

Abstract: As no exact model of traffic flow exists due to its high complexity and chaotic organisation, researchers mainly try to predict traffic using simulations. Within this field, many simulation packages exist and differ in their software architecture paradigm as well as in the models that describe traffic itself. We will introduce yet another system which, in contrast to most of the other simulation software packages, is available as on open-source programm and may therfore be extended in order to fit a researcher´s own needs and also be used as a reference testbed for new traffic models.

Analyzing peer-to-peer traffic across large networks

Abstract: The use of peer-to-peer (P2P) applications is growing dramaticaliy, particularly for sharing large video/audio files and software. In this paper, we analyze P2P traffic by measuring flow-level information collected at multiple border routers across a large ISP network, and report our investigation of three popular P2P systems -- FastTrack, Gnutella, and DirectConnect. We characterize the P2P traffic observed at a single ISP and its impact on the underlying network. We observe very skewed distribution in the traffic across the network at different levels of spatial aggregation (IP, prefix, AS). All three P2P systems exhibit significant dynamics at short times scale and particularly at the IP address level Still, the fraction of P2P traffic contributed by each prefix is much more stable than the corresponding distribution of either Web traffic or overall traffic. The high volume and good stability properties of P2P traffic indicates that the P2P workload is a good candidate for being managed via application-specific layer-3 traffic engineering in an ISP's network.

Network traffic generation and monitoring systems and methods for their use in testing frameworks for determining suitability of a network for target applications

Abstract: A system for monitoring traffic on a network first discovers the network so as to map the various devices and links in the network. Statistics are then gathered from various points in the network relating to quality of service, and especially loads on the network devices. Synthetic calls are generated at selected points of the network while monitoring the network. This data is then stored and displayed in a manner that is easy for the operator to analyze, with more detailed displays being available through the use of a mouse or keystrokes.

Experience in measuring backbone traffic variability: models, metrics, measurements and meaning

Abstract: Understanding the variability of Internet traffic in backbone networks is essential to better plan and manage existing networks, as well as to design next generation networks. However, most traffic analyses that might be used to approach this problem are based on detailed packet or flow level measurements, which are usually not available throughout a large network. As a result there is a poor understanding of backbone traffic variability, and its impact on network operations (e.g. on capacity planning or traffic engineering).This paper introduces a metric for measuring backbone traffic variability that is grounded on simple but powerful traffic theory. What sets this metric apart, however, is that we present a method for making practical measurements of the metric using widely available SNMP traffic measurements. Furthermore, we use a novel method to overcome the major limitation of SNMP measurements -- that they only provide link statistics. The method, based on a "gravity model", derives an approximate traffic matrix from the SNMP data. In addition to simulations, we use more than 1 year's worth of SNMP data from an operational IP network of about 1000 nodes to test our methods. We also delve into the degree and sources of variability in real backbone traffic, providing insight into the true nature of traffic variability.

Network game traffic modelling

Abstract: A significant share of today's Internet traffic is generated by network gaming. This kind of traffic is interesting in regard to it's market potential as well as to it's real time requirements on the network. For the consideration of game traffic in network dimensioning, traffic models are required that allow to generate a characteristic load for analytical or simulative performance evaluation of networks. In this paper we evaluate the fast action multiplayer game ,,Counter Strike" from a 36 hour LAN party measurement and present traffic models for client and server. The paper concludes with remarks on the use of game traffic models in simulations and on QoS metrics for an adequate evaluation of simulation results.

Systems and methods for identifying anomalies in network data streams

Abstract: A traffic auditor ( 130 ) analyzes traffic in a communications network ( 100 ). The traffic auditor ( 130 ) performs traffic analysis on traffic in the communications network ( 100 ) and develops a model of expected traffic behavior based on the traffic analysis. The traffic auditor ( 130 ) analyzes traffic in the communications network ( 100 ) to identify a deviation from the expected traffic behavior model.

Self-similar traffic and network dynamics

Abstract: One of the most significant findings of traffic measurement studies over the last decade has been the observed self-similarity in packet network traffic. Subsequent research has focused on the origins of this self-similarity, and the network engineering significance of this phenomenon. This paper reviews what is currently known about network traffic self-similarity and its significance. We then consider a matter of current research, namely, the manner in which network dynamics (specifically, the dynamics of transmission control protocol (TCP), the predominant transport protocol used in today's Internet) can affect the observed self-similarity. To this end, we first discuss some of the pitfalls associated with applying traditional performance evaluation techniques to highly-interacting, large-scale networks such as the Internet. We then present one promising approach based on chaotic maps to capture and model the dynamics of TCP-type feedback control in such networks. Not only can appropriately chosen chaotic map models capture a range of realistic source characteristics, but by coupling these to network state equations, one can study the effects of network dynamics on the observed scaling behavior We consider several aspects of TCP feedback, and illustrate by examples that while TCP-type feedback can modify the self-similar scaling behavior of network traffic, it neither generates it nor eliminates it.

Geo-intelligent traffic manager

Abstract: A traffic manager (30) determines the geographic locations of end points on Internet traffic and routes the traffic in the most efficient manner. A set of analyzers may be disposed to analyze the network, such as the geographic locations of nodes in the network, latency times and speed between nodes, available bandwidth, etc. The traffic manager obtains this intelligence on the network from the analyzers and routes traffic accordingly. The traffic manager considers not only the most direct route but also considers the speed, available bandwidth, and reliability of the routing.

Traffic data management and simulation system

Abstract: Systems and methods for geographically based analyses of traffic being carried over a wide scale traffic network (10). The systems integrate (12) geographical information systems (GIS) with traffic simulation processes (18, 20) to allow a user to analyze traffic patterns and loads at specific geographic locations of regions. Additionally, these systems allow for traffic analysis over a wide scale traffic network that may encompass the traffic network that exists within an geographic region and can include, as examples, the traffic networks that span across a city, that interconnect cities, that interconnect states and that run across multiple states. To this end, the systems include traffic simulators that can adaptively or controllably select between multiple traffic simulation models for simulating traffic across different segments of the traffic network (18, 20). The different models provide varying levels of granularity for measurements of geographical location of a vehicle traveling over the traffic network. Thus, portions of the traffic network that are to be analyzed more closely can use the traffic simulator model with the highest degree of granularity, while traffic patterns across other areas of the network may be modeled with lower granularity models that may provide for computational efficiency.

Ad hoc wireless network traffic-self-similarity and forecasting

Abstract: Lots of works have been carried out to discuss the self-similarity of Ethernet and World Wide Web traffic. In this letter, we study the ad hoc wireless network traffic collected in an ad hoc network (AHN) testbed and show that the ad hoc wireless network traffic is self-similar, which validates that AHN traffic is forecastable because self-similar time-series can be forecasted. We apply a fuzzy logic system to ad hoc wireless network traffic forecasting and simulation results show that it performs much better than does an LMS adaptive filter. All these studies are very important for evaluating network capacity and determining the battery power mode based on the forecasted traffic workload.

Multi agent simulation of unorganized traffic

Abstract: Traffic simulation is one of the most complex simulation projects that can be undertaken. The main issues are: modeling of autonomous behavior of drivers, modeling of their interaction, and ability to simulate the traffic and procure reliable realistic results. Organized traffic with drivers heeding to well defined traffic rules is less dynamic and erratic, than modeling unorganized traffic, wherein the drivers either do not heed to well defined traffic rules, or there are no traffic rules in place. This paper shows the viability of applying multi-agent simulation for unorganized traffic. In particular, we model the behavior of drivers, as being cautious, normal, and aggressive, and show results about average speed of vehicles in traffic, number of overtakes, and number of accidents occurring with different proportions of aggressive and cautious drivers. A multi-agent simulator with graphics interface has been implemented to visualize and evaluate the traffic flow.

A combined procedure for optimization via simulation

Abstract: We propose an optimization-via-simulation algorithm for use when the performance measure is estimated via a stochastic, discrete-event simulation, and the decision variables may be subject to deterministic linear integer constraints. Our approach-which consists of a global guidance system, a selection-of-the-best procedure, and local improvement-is globally convergent under very mild conditions.

tcplib: A Library of TCP Internetwork Traffic Characteristics

Abstract: This paper describes tcplib, a workload or source library for network simulation. This paper motivates the need for tools like tcplib and discusses how to incorporate it into a network simulator. Tcplib is available by anonymous ftp1.

Scheduling updates of electronic files

Abstract: In scheduling updates of original electronic files, an upgrade system receiving new electronic files generates target lists of host device models/users that are to receive the new file information. The new file information includes upgrades and/or upgrade notifications. In response to the target lists, the upgrade system uses delivery rules to generate a delivery schedule for delivery of the information to the devices. The upgrade system executes a network traffic simulation using the delivery schedule. The simulation applies the delivery schedule to the network in order to estimate the network traffic capacity that would result from transferring the new file information in accordance with the delivery schedule. The upgrade system refines the delivery schedule, using results of the simulation, in order to optimize network performance. The upgrade system transmits the new file information to the appropriate devices in accordance with the refined delivery schedule.

COST: a component-oriented discrete event simulator

Abstract: COST (Component-Oriented Simulation Toolkit) is a general-purpose discrete event simulator. The main design purpose of COST is to maximize the reusability of simulation models without losing efficiency. To achieve this goal, COST adopts a component-based simulation worldview based on a component-port model. A simulation is built by configuring and connecting a number of components, either off-the-shelf or fully customized. Components interact with each other only via input and output ports, thus the development of a component becomes completely independent of others. The component-port model of COST makes it easy to construct simulation components from scratch. Implemented in C++, COST also features a wide use of templates to facilitate language-level reuse.

Design of WDM mesh networks with sparse grooming capability

Abstract: In a WDM optical network, the bandwidth requirement of a customer's connection can vary over a wide range, and many of these connections could have a capacity that is much lower than the capacity of a wavelength channel. Efficiently grooming low-speed connections onto high-capacity wavelength channels can significantly improve the bandwidth utilization and minimize the network cost. Our research shows that it is not necessary to have traffic-grooming capability at every network node. We call a network which has only a few grooming nodes to be a sparse-grooming network. Through proper network design and traffic engineering, it is possible for a sparse-grooming network to achieve similar network performance as a network which has grooming capability at every node. We investigate the problem of designing such a sparse-grooming WDM mesh network. The problem is mathematically formulated and several design schemes are proposed. Illustrative numerical results from the mathematical formulation as well as heuristics show that, by properly choosing the grooming nodes, a network with sparse-grooming capability can achieve good network performance and the network cost can be significantly reduced.

Performance engineering and topological design of metro WDM optical networks using computer simulation

Abstract: This paper demonstrates the use of computer simulation for topological design and performance engineering of transparent wavelength-division multiplexing metropolitan-area networks. Engineering of these networks involves the study of various transport-layer impairments such as amplifier noise, component ripple, chirp/dispersion, optical crosstalk, waveform distortion due to filter concatenation, fiber nonlinearities, and polarization effects. A computer simulation methodology composed of three main simulation steps is derived and implemented. This methodology obtains performance estimations by applying efficient wavelength-domain simulations on the entire network topology, followed by time-/frequency-domain simulations on selected paths of the network and finally Q-budgeting on an identified worst case path. The above technique provides an efficient tool for topological design and network performance engineering. Accurate simulation models are presented for each of the performance impairments, and the computer simulation methodology is used for the design and engineering of a number of actual metro network architectures.

Method and system for enhancing performance of a physical network under real-time control using simulation of a reference model

Abstract: A system and method for network simulation and enhancement includes an experiment configuration engine that provides various proposed traffic and/or network models, and a simulator responsive to the proposed traffic and/or network models to execute a plurality of simulations for the network using parallel discrete event simulation, to determine an optimal network configuration based upon an objective function for enhancing an aspect of network performance. The traffic and/or network models may be based on monitored data from the network indicating a current network state and current network traffic. Reconfiguration instructions for the new network configuration may be conveyed from the simulator to the network, so as to effectuate ongoing, real-time enhancement of the network. The network model(s) may cover internal operational details of individual network devices (e.g., routers and/or switches) as well as operation of the network as a whole.

Patterns and performance of a CORBA event service for large-scale distributed interactive simulations.

Abstract: Advanced distributed interactive simulations have stringent quality of service (QoS) requirements for throughput, latency, and scalability, as well as requirements for a flexible communication infrastructure to reduce software lifecycle costs. The CORBA Event Service provides a flexible model for asynchronous communication among distributed and collocated objects. However, the standard CORBA Event Service specification lacks important features and QoS optimizations required by distributed interactive simulation systems. This paper makes five contributions to the design, implementation, and performance measurement of distributed interactive simulation systems. First, it describes how the CORBA Event Service can be implemented to support key QoS features. Second, it illustrates how to extend the CORBA Event Service so that it is better suited for distributed interactive simulations, such as the next-generation Run Time Infrastructure (RTI-NG) implementation for the Defense Modeling and Simulation Organization’s (DMSO) High Level Architecture (HLA). Third, it describes how to develop efficient event dispatching and scheduling mechanisms that can sustain high throughput. Fourth, it describes how to use multicast protocols to reduce network traffic transparently and to improve system scalability. Finally, it illustrates how an Event Service framework can be strategized to support configurations that facilitate high throughput, predictable bounded latency, or some combination of each.

Models for traffic control

Abstract: Traffic models play an Important role in both today's traffic research and in many traffic applications such as traffic flow prediction, incident detection and traffic control. In this paper we concentrate on motorway traffic models for traffic control. First, we discuss why traffic control Is Important for both practice and research. We also argue why a model-based approach to traffic control Is used and how it Is implemented In traffic applications. Every traffic application requires specific features of the traffic model. After classifying the models based on these features, we look In detail at three macroscopic models since these models are best suited for implementation In traffic control systems. We conclude with an illustrative example that illustrates a model-based predictive control approach for ramp metering.

Planning reliable UMTS terrestrial access networks

Abstract: The Universal Mobile Telecommunication System (UMTS) will play a very important role in the telecommunication market of the near future. Due to the wide range of services and the increased transmission capacity, UMTS will become one of the most important access network types. The proposed topology of the UMTS terrestrial access network is tree-like, but the high amount of carried traffic requires a more reliable network structure. We introduce two types of heuristic algorithms to solve this problem, and we plan network topologies having a low magnitude of traffic loss in case of failures. One of our algorithms solves the problem by modifying the tree-topology, while others expand the network by inserting additional links. We show how to find a good compromise between topology refinement and network expansion in the case of realistic network scenarios, and we confirm our results by detailed tests.

An Example of Microscopic Car Models Validation using the open source Traffic Simulation SUMO

Abstract: In SUMO (Simulation of Urban MObility; An open-source traffic simulation) we presented an open source simulation software for road traffic simulation. Now we show one possible field of application, the validation of microscopic car/car-driver models. Our motivation is to awake the interest in using and extending the software, so this report will describe the software´s usability but will not go into depth in interpreting the results.

Provisioning internet backbone networks to support latency sensitive applications

Abstract: Interactive applications such as voice, audio, and video, as well as business applications such as Virtual Private Networks are becoming an increasingly important component of Internet traffic. Such applications have strict requirements on the total end-to-end delay which may be incurred in the network. One approach to meeting these delay requirements, known as service differentiation, is to give preferential treatment to latency sensitive traffic. Doing so may lead to an efficient network design with the minimum amount of resources (e.g., bandwidth) required to support the needs of each traffic type. An alternative approach is to provide sufficient resources so that all traffic meets the most stringent delay requirements. This latter approach is known as overprovisioning. In the context of wide-area Internet backbone networks, two factors make overprovisioning an attractive approach. First, the high link speeds and large volumes of traffic make service differentiation complex and potentially costly to deploy. Second, given the degree of aggregation and resulting traffic characteristics, the amount of overprovisioning required may not be very large. We establish that this is indeed the case by collecting and analyzing traffic measurements from the Sprint IP network, a commercial Tier-1 Internet backbone. We begin by performing network simulations using a set of 331 one-hour traffic measurements from the Sprint network. These simulations demonstrate that link utilization can reach 80%–90% before queuing delays begin to exceed several milliseconds. While the simulations can be used to evaluate the level of overprovisioning required in the network, many network design problems are greatly aided by an analytic traffic model. We therefore develop a traffic model which captures the observed characteristics of backbone traffic and derive expressions for the delay through a single queue in the network, as well as the end-to-end queuing delay. Using this model we solve several network design problems including capacity planning and optimal route selection.

A framework for parallel traffic simulation using multiple instancing of a simulation program

Abstract: Parallel traffic simulation is an application of parallel computing techniques that aims to decrease the computation time by engaging different processors of a multiprocessor system or different computers of a network. Very few traffic simulation models have this capability of parallel simulation. However, it is possible to upgrade a simulation program that is not capable of running parallel simulation by applying the method proposed in this article. The method involves dividing the network into regions and simulating each region under a separate instance of the program. Suitable interprocess communication techniques are employed to exchange data between different regions and synchronize time among the different regions. A significant increase in simulation speed is seen when the proposed method is applied to Paramics, a microscopic time-stepping simulation program.

Rapid model parameterization from traffic measurements

Abstract: The utility of simulations and analysis heavily relies on good models of network traffic. While network traffic constantly is changing over time, existing approaches typically take years from collecting trace, analyzing the data to finally generating and implementing models. In this paper, we describe approaches and tools that support rapid parameterization of traffic models from live network measurements. Rather than treating measured traffic as a time-series of statistics, we utilize the traces to estimate end-user behavior and network conditions to generate application-level simulation models. We also show multi-scaling analytic techniques are helpful for debugging and validating the model. To demonstrate our approaches, we develop structural source-level models for web and FTP traffic and evaluate their accuracy by comparing the outputs of simulation against the original trace. We also compare our work with existing traffic generation tools and show our approach is more flexible in capturing the heterogeneity of traffic. Finally, we automate and integrate the process from trace analysis to model validation for easy model parameterization from new data.

Evolutionary swarm traffic: if ant roads had traffic lights

Abstract: Traffic congestion has become a major concern for many cities throughout the world. Consequently, simulations can provide helpful tools for engineers to plan traffic systems. We present SuRJE, a swarm-based traffic simulation system. All interactions among individual drivers are implemented through the dropping and sniffing of pheromones on a 2-dimensional map. Furthermore, SuRJE optimizes traffic light turn and time sequences using an evolutionary algorithm and swarm voting, which helps to speed up the adaptation process for the traffic light settings.