Special issue on Tools, Modelling Techniques and Analysis Aspects of Heterrogeneous Networks
Parallel Network Simulation with OMNeT++ (pp: 5 – 14)
András Varga 1, Ahmet Y. Şekercioğlu 2
1 OpenSim Ltd, Budapest, Hungary
2 Centre for Telecommunication and Information Engineering, Monash University, Melbourne, Australia
Abstract: This paper reports a new parallel and distributed simulation architecture for OMNeT++, an open-source discrete event simulation environment. The primary application area of OMNeT++ is the simulation of communication networks. Support for a conservative PDES protocol (the Null Message Algorithm) and the relatively novel Ideal Simulation Protocol has been implemented. Placeholder modules, a novel way of distributing the model over several logical processes (LPs) is presented. The OMNeT++ PDES implementation has a modular and extensible architecture, allowing new synchronization protocols and new communication mechanisms to be added easily, which makes it an attractive platform for PDES research, too. We intend to use this framework to harness the computational capacity of high-performance cluster computers for modeling very large scale telecommunication networks to investigate protocol performance and rare event failure scenarios.
An Efficient Statistical Synchronization Method for Parallel Simulation (pp: 15 – 23)
Gábor Lencse
Department of Telecommunications, Széchenyi István University, Győr, Hungary
Abstract: : In this paper, we propose the improved Statistical Synchronization Method (SSM-T) for parallel discrete event simulation. Criteria are given for the time-driven approach (SSM‑T). It is proven that the level of the output error can be guaranteed. SSM-T is implemented in the OMNeT++ discrete event simulation tool, which is a useful and widespread framework for creating various simulation models to evaluate the performance of telecommunication networks. Case studies have been performed, which shows that SSM‑T is a very efficient synchronization method for the parallel simulation of communication networks.
Internet Service Providers’ Pricing Strategies for Loyal Customers (pp: 24 – 31)
Trinh Anh Tuan 1, Nguyen Dinh Chien 2
1 Budapest University of Technology and Economics, Hungary
2 Viettel Technologies, Vietnam
Abstract: In this paper, we investigate the impacts of user behaviour – user loyalty in particular – on pricing strategies of Internet Service Providers (ISPs) for a profitable yet sustainable Internet access marketplace. First, we propose a realistic user loyalty model, the price difference dependent loyalty model, which is based on empirical evidences from ISPs in different countries in the world. Next, we apply the loyalty model in game-theoretical analyses where optimal Internet access pricing strategies are expressed. Finally, we present the impacts of user loyalty on the prices and profits of ISPs in different scenarios based on simulation results.
Call-level Analysis of Hybrid WDM-OCDMA Passive Optical Networks with Finite Traffic Sources (pp: 32 – 42)
John S. Vardakas, Vassilios G. Vassilakis and Michael D. Logothetis
Wire Communications Laboratory, Dept. of Electrical and Computer Engineering, University of Patras, 265 04, Patras, Greece
Abstract: Passive Optical Networks (PONs) are becoming a mature concept for the provision of enormous bandwidth to end-users with low cost. In this paper we study the call-level performance of two PON configurations: the OCDMA-PON and the Hybrid WDM-OCDMA PON. We propose analytical models for calculating connection failure probabilities (due to unavailability of a wavelength) and call blocking probabilities (due to the total interference on a call that may exceed a permissible threshold) in the upstream direction. The PONs are described/modeled by one-dimensional Markov chains. By solving them, we derive recurrent formulas for the blocking probabilities. The proposed analytical models are validated through simulation; their accuracy was found to be absolutely satisfactory.
Multipath Video Streaming Using GRA Network Ordering Algorithm without Rank Inconsistency (pp: 43 – 58)
Árpád Huszák, Sándor Imre
Budapest University of Technology and Economics, Department of Telecommunications, Budapest, Hungary
Abstract: Simultaneous connection to several networks through multiple interfaces is possible with today’s mobile terminals. In order to efficiently utilize the interfaces’ capabilities and increase the quality of the streamed video, multipath streaming can be used. Resource intensive applications can deliver high bitrate streams over multiple paths by cumulating the available bandwidth of the different subpaths. In this paper we propose a multipath streaming method that chooses a set of paths maximizing the overall quality at the client. While the available paths have different bandwidth, delay and loss probability constrains, the packet distributor must take the video packet importance and the dependencies between packets into account. In order to efficiently distribute the packets, the link must be ordered based on the network attributes. Grey Relational Analysis (GRA) is a promising algorithmic approach that can realize dynamic interface ordering with multiple alternatives (interfaces) and attributes (network parameters). However similarly to some other decision methods, GRA also suffers from rank reversal phenomenon. Transmitting the reference video frames on the most reliable links will decrease the loss probability of important data packets and increase the measured video quality. The change of link order can lead to frequent handovers causing the degradation of the observed video quality.
Novel Applications of the Peer-to-peer Communication Methodology (pp: 59 – 70)
Loránd Lehel Tóth, Zoltán Czirkos, Gábor Hosszú and Ferenc Kovács
Department of Electron Devices, Budapest University of Technology and Economics
Abstract: In this article we represent two novel applications that make extensive use of the peer-to-peer communication method. Dolphin is a file sharing system with improved reliability and searching efficiency compared to other popular file sharing applications. Komondor is a peer-to-peer based security application, a network intrusion detection system that relies on the collaboration of network hosts. These two applications base their speed, stability and robustness on the application level network they create./.
