On the parallel simulation of scale-free networks (original) (raw)

Simulation of Scale-Free Networks

Proceedings of 2nd ACM/ICST International Conference on Simulation Tools and Techniques (SIMUTools 2009)., 2009

In this paper, we present a new simulation tool for scale-free networks composed of a high number of nodes. The tool, based on discrete-event simulation, enables the definition of scale-free networks composed of heterogeneous nodes and complex application-level protocols. To satisfy the performance and scalability requirements, the simulator supports both sequential (i.e. monolithic) and parallel/distributed (i.e. PADS) approaches. Furthermore, appropriate mechanisms for the communication overhead-reduction are implemented. To demonstrate the efficiency of the tool, we experiment with gossip protocols on top of scale-free networks generated by our simulator. Results of the simulations demonstrate the feasibility of our approach. The proposed tool is able to generate and manage large scale-free networks composed of thousands of nodes interacting following real-world dissemination protocols.

Conservative synchronization of large-scale network simulations

18th Workshop on Parallel and Distributed Simulation, 2004. PADS 2004., 2004

Parallel discrete event simulation techniques have enabled the realization of large-scale models of communication networks containing millions of end hosts and routers. However, the performance of these parallel simulators could be severely degraded if proper synchronization ...

Micro-Synchronization in Conservative Parallel Network Simulation

2008

Lookahead is a critical factor in conservative parallel simulation. Greater lookahead usually brings better performance. However, in the simulation of computer networks, lookahead is usually determined by the minimal delay of the border links between any two subnets that simulated by different sequential logical processes (LPs), which is too small to get good performance. Traditionally, the lookahead exploitation usually only reflects the parallelism among LPs, which possibly wastes the potential parallelism inside each LP, especially, in the case that each LP simulates thousands of entities. Here we present a simple method called micro-synchronization to exploit the parallelism inside each LP. Different from the previous work, such as lookahead accumulation and local time warp, we keep the traditional usage of lookahead among LPs unchanged, and however, we impose the relaxed sequential event scheduling inside each LP, which can indirectly improve the lookahead. We also present a state causality model to prove the correctness of our method, which means that there is no risk in the relaxed sequential execution. Finally, the experiment evaluates our method and shows that it can improve the performance of conservative parallel simulation of computer networks to some extent.

Parallel simulation techniques for large-scale networks

IEEE Communications Magazine, 1998

Simulation has always been an indispensable tool in the design and analysis of telecommunication networks. Due to performance limitations of the majority of simulators, usually network simulations have been done for rather small network models and for short time scales. In contrast, many di cult design problems facing today's network engineers concern the behavior of very large, hierarchical multi-hop networks carrying millions of multiprotocol ows, over long time scales. Examples include scalability and stability of routing protocols, packet losses in core routers, or long-lasting transient b e h a viors due to observed self-similarity of tra c patterns. Simulation o f s u c h systems would greatly bene t from application of parallel computing technologies, especially now that multiprocessor workstations and servers have become commonly available. However, parallel simulation has not yet been widely embraced by telecommunications community due to a number of di culties. Based on our accumulated experiences in parallel network simulation projects, we believe that parallel simulation technology has matured to the point that it is ready to be used in industrial practice of network simulation. This article highlights recent w ork in parallel simulations of networks and its promises.

Genesis: A scalable distributed system for large-scale parallel network simulation

2006

The complexity and dynamics of the Internet is driving the demand for scalable and efficient network simulation. In this paper, we describe a novel approach to scalability and efficiency of parallel network simulations. This approach is based on partitioning of a network into domains and of the simulation time into intervals. Each domain is simulated independently of and concurrently with the others over the same simulation time interval.

A Generic Framework for Parallelization of Network Simulations

1999

Discrete event simulation is widely used within the networking community for purposes such as demonstrating the validity of network protocols and architectures. Depending on the level of detail modeled within the simulation, the running time and memory requirements can be excessive. The goal of our research is to develop and demonstrate a practical, scalable approach to parallel and distributed simulation that will enable widespread reuse of sequential network simulation models and software. We focus on an approach to parallelization where an existing network simulator is used to build models of subnetworks that are composed to create simulations of larger networks. Changes to the original simulator care minimized, enabling the parallel simulator to easily track enhancements to the sequential version. We describe our lessons learned in applying this approach to the publicly available ns software package (McCanne and Floyd, 1997) and converting it to run in a parallel fashion on a network of workstations. This activity highlights a number of important problems, from the standpoint of how to parallelize an existing serial simulation model and achieving acceptable parallel performance

Synchronization landscapes in small-world-connected computer networks

Physical Review E, 2006

Motivated by a synchronization problem in distributed computing we studied a simple growth model on regular and small-world networks, embedded in one and two-dimensions. We find that the synchronization landscape (corresponding to the progress of the individual processors) exhibits Kardar-Parisi-Zhang-like kinetic roughening on regular networks with short-range communication links. Although the processors, on average, progress at a nonzero rate, their spread (the width of the synchronization landscape) diverges with the number of nodes (desynchronized state) hindering efficient data management. When random communication links are added on top of the one and two-dimensional regular networks (resulting in a small-world network), large fluctuations in the synchronization landscape are suppressed and the width approaches a finite value in the large system-size limit (synchronized state). In the resulting synchronization scheme, the processors make close-to-uniform progress with a nonzero rate without global intervention. We obtain our results by "simulating the simulations", based on the exact algorithmic rules, supported by coarse-grained arguments. * Permanent address: Center for Nonlinear Studies, Theoretical Division, Los Alamos National Laboratory, MS-B258, Los Alamos, NM, USA, 87545 SW-like synchronization network for PDES can have a strong impact on the scalability of the algorithm . Secondly, since the particular problem is effectively "local" relaxation in a noisy environment in a SW network, our study also contributes to the understanding of collective phenomena on these networks.

Parallel network simulation under distributed Genesis

2003

Abstract We describe two major developments in the General Network Simulation Integration System (Genesis): the supportfor BGP protocol in large network simulations and distributionof the simulation memory among Genesis componentsimulations. Genesis uses a high granularity synchronization mechanismbetween parallel simulations simulating parts of a network. This mechanism uses checkpointed simulation stateto iterate over the same time interval until convergence.

Small-World Synchronized Computing Networks for Scalable Parallel Discrete-Event Simulations

Complex Networks, 2004

We study the scalability of parallel discrete-event simulations for arbitrary short-range interacting systems with asynchronous dynamics. When the synchronization topology mimics that of the short-range interacting underlying system, the virtual time horizon (corresponding to the progress of the processing elements) exhibits Kardar-Parisi-Zhang-like kinetic roughening. Although the virtual times, on average, progress at a nonzero rate, their statistical spread diverges with the number of processing elements, hindering efficient data collection. We show that when the synchronization topology is extended to include quenched random communication links between the processing elements, they make a close-to-uniform progress with a nonzero rate, without global synchronization. We discuss in detail a coarse-grained description for the small-world synchronized virtual time horizon and compare the findings to those obtained by "simulating the simulations" based on the exact algorithmic rules.