IMPLEMENTING THE DISTRIBUTED BREADTH FIRST SEARCH ALGORITHM IN OMNET++ FOR TEACHING AND LEARNING PURPOSES

Year 2016, Volume: 5 , 42 - 46, 01.09.2016

Esranur Galip Hasan Bulut

Abstract

A distributed system is considered as a set of
computers communicating through the network and running collaboratively to
coordinate their activities and to share the resources of the system to achieve
a common goal. The coordination is achieved by exchanging messages, which carry
information. Distributed algorithms play a crucial role in this coordination.
However, teaching and learning distributed algorithms is difficult due to the
inherent complexities of the distributed system. Since it is costly to construct
a network of computers to run distributed algorithms to conduct research, teach
and learn, many commercial and freely available open source simulation tools
have been developed for simulating network systems and hence, distributed
systems. These tools facilitate the development of distributed algorithms for
different environments. One of these tools is OMNET++, which is a
component-based C++ simulation library and framework for building network
simulators and offers a graphical runtime environment.To facilitate the
understanding of the working mechanism, a distributed system can be modeled as
a graph. Each computer in the distributed system is represented by a vertex,
called node and a link between two computers is represented by an edge. Hereby,
many graph algorithms can be utilized within a distributed system. For
instance, traversal of computers (nodes) in a distributed system is important
and used for solving many problems. Many algorithms provide traversal of nodes.
In this study, we would like to demonstrate the use of a simulation tool for
teaching and learning one of the fundamental distributed graph algorithms
called Breadth First Search (BFS) algorithm. We use OMNET++ to visualize the
steps of constructing a BFS tree, where colors of edges are dynamically changed
to indicate the inner workings of the algorithm. In addition, a learner can
visually trace the flow of the messages between nodes in the simulation.

Keywords

Distributed algorithms, graph algorithms, breadth first search algorithm, simulation for education, omnet++

References

• Abdou, W., Abdallah, N., & Mosbah, M. (2014). ViSiDiA: A Java Framework for Designing, Simulating and Visualizing Distributed Algorithms. IEEE/ACM 18th International Symposium on Distributed Simulation and Real Time Applications (DS-RT), 43-46. András Varga, R. H. (2008). An overview of the OMNeT++ simulation environment. In Proceedings of the 1st international conference on Simulation tools and techniques for communications, networks and systems & workshops, 60. ICST (Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering. Easley, D., & Kleinberg, J. (2010). Networks, Crowds, and Markets: Reasoning about a Highly Connected World. Cambridge University Press. Fouh, E., Akbar, M., & Shaffer, C. A. (2012). The Role of Visualization in Computer Science Education. Computers in the Schools, 95-117. O'Donnell, F. (2006). Simulation Frameworks for the Teaching and Learning of Distributed Algorithms. Thesis of Doctor of Philosophy. University of Dublin, Trinity College. OMNET++. (2016). OMNeT++ Discrete Event Simulator. Retrieved March 15, 2016 from https://omnetpp.org/ Raynal, M. (2013). Distributed Algorithms for Message-Passing Systems. London: Springer. Thomas Naps, S. C. (2003). Evaluating the educational impact of visualization. ACM SIGCSE Bulletin, 35(4), 124-136. University of Eastern Finland. (2016). Jeliot3. Jeliot3. Retrieved March 15, 2016 from https://cs.joensuu.fi/jeliot/downloads/jeliot372.php Varga, A. (1999). Using the OMNeT++ Discrete Event Simulation System in Education. IEEE Transaction on Education, 42(4), 372.